Hugh Calkins, MD, FHRS; Josep Brugada, MD, FESC; Douglas L. Packer, MD, FHRS;

Riccardo Cappato, MD, FESC; Shih-Ann Chen, MD, FHRS; Harry J.G. Crijns, MD, FESC;

Ralph J. Damiano, Jr., MD; D. Wyn Davies, MD, FHRS; David E. Haines, MD, FHRS;

Michel Haissaguerre, MD; Yoshito Iesaka, MD; Warren Jackman, MD, FHRS; Pierre Jais, MD;

Hans Kottkamp, MD; Karl Heinz Kuck, MD, FESC; Bruce D. Lindsay, MD FHRS;

Francis E. Marchlinski, MD; Patrick M. McCarthy, MD; J. Lluis Mont, MD, FESC; Fred Morady, MD;

Koonlawee Nademanee, MD; Andrea Natale, MD, FHRS; Carlo Pappone, MD, PhD;

Eric Prystowsky, MD, FHRS; Antonio Raviele, MD, FESC; Jeremy N. Ruskin, MD; Richard J. Shemin, MD

TASK FORCE MEMBERS:

Hugh Calkins, MD, FHRS, Chair, Johns Hopkins Hospital, Maryland, USA

Josep Brugada, MD, FESC, Co-Chair, EHRA representative, Hospital Clinic, University of Barcelona, SPAIN

Veterans General Hospital, TAIWAN

Indiana, USA

Georg, Hamburg, GERMANY

Hospital, Maryland, USA

University School of Medicine, Missouri, USA

Medicine, Illinois, USA

1547-5271/$ -see front matter © 2007 by the Heart Rhythm Society and the European Heart Rhythm Association,

registered branch of the European Society of Cardiology. doi:10.1016/j.hrthm.2007.04.005

Riccardo Cappato, MD, FESC, ECAS representative, Arrhythmia and EP Center, Milan, ITALY

Harry J.G. Crijns, MD, PhD, FESC, University Hospital Maastricht, THE NETHERLANDS

Ralph J. Damiano, Jr., MD, Washington University School of Medicine, Missouri, USA

Michel Haissaguerre, MD, Université De Bordeaux, Hôpital Cardiologique, FRANCE

Warren M. Jackman, MD, FHRS, University of Oklahoma Health Science Center, USA

Pierre Jais, MD, Université De Bordeaux, Hôpital Cardiologique, FRANCE

Yoshito Iesaka, MD, Tsuchiura Kyodo Hospital, JAPAN

Hans Kottkamp, MD, Clinic Hirslanden Zurich, SWITZERLAND

Lluis Mont, MD, FESC Hospital Clinic, University of Barcelona, SPAIN

Fred Morady, MD, University of Michigan Hospital, USA

Koonlawee Nademanee, MD, Pacific Rim EP Research Institute Center, California, USA

Carlo Pappone, MD, PhD, Hospital San Raffaele, Milano, ITALY

Antonio Raviele, MD, FESC, Umberto I Hospital, Venice, ITALY

Jeremy N. Ruskin, MD, Massachusetts General Hospital, USA

Richard J. Shemin, MD, David Geffen School of Medicine at UCLA, California, USA

I. Introduction ..................................................................818

II. Atrial Fibrillation: Definitions, Mechanisms, and

Rationale for Ablation...............................................818

Definitions........................................................................818

Mechanisms of Atrial Fibrillation...................................819

Electrophysiologic Basis for Catheter Ablation of

Atrial Fibrillation.......................................................822

Rationale for Eliminating Atrial Fibrillation with Ablation.......823

III. Indications for Catheter Ablation of Atrial

Fibrillation and Patient Selection..............................823

Patient Selection for Catheter Ablation of Atrial

Fibrillation..................................................................824

IV. Techniques and Endpoints for Atrial

Fibrillation Ablation.............................................824

Historical Considerations ................................................824

Ablation Approaches Targeting the Pulmonary Veins.......824

Ablation Approaches Not Targeting the

Pulmonary Veins .......................................................825

Task Force Consensus.....................................................825

V. Technologies and Tools .............................................826

Energy Sources—Radiofrequency Energy......................826

Alternate Energy Sources................................................826

Multielectrode Circumferential Mapping Catheter.........827

Electroanatomic Mapping Systems.................................827

Intracardiac Echocardiography........................................827

Pulmonary Vein Venography..........................................828

CT and MR Imaging of the Atrium and

Pulmonary Veins .......................................................828

VI. Other Technical Aspects...........................................828

Anticoagulation and Strategies to Prevent

Thromboembolism................................................828

Anesthesia/Sedation During Ablation.............................830

Esophageal Monitoring....................................................831

VII. Follow-up Considerations........................................831

ECG Monitoring Pre and Post Procedure ......................831

Available Methods for Arrhythmia Monitoring .............832

Follow-up and Monitoring Guidelines for Routine

Clinical Care..............................................................832

Early Recurrence of Atrial Fibrillation...........................832

Atrial Tachycardias after Atrial Fibrillation Ablation ........833

Antiarrhythmic and Other Drug Therapy Post Ablation.......833

Repeat Atrial Fibrillation Ablation Procedures ..............834

Autonomic Alterations ....................................................834

VIII. Outcomes and Efficacy of Catheter Ablation of

Atrial Fibrillation.......................................................834

Overview..........................................................................834

Published Literature Review ...........................................835

Impact of Catheter Ablation of Atrial Fibrillation on

Quality of Life...........................................................836

Impact of Catheter Ablation of Atrial Fibrillation on

LA Size and Function ...............................................836

Impact of Catheter Ablation of Atrial Fibrillation on

Left Ventricular Function..........................................837

IX. Complications of Atrial Fibrillation Ablation..........837

Cardiac Tamponade.........................................................837

Pulmonary Vein Stenosis ................................................838

Esophageal Injury/Atrio-esophageal Fistula ...................838

Phrenic Nerve Injury .......................................................839

Thrombo-Embolism.........................................................839

Post-procedural Arrhythmias...........................................840

Radiation Exposure During Catheter Ablation of Atrial

Fibrillation..................................................................841

Mitral Valve Trauma.......................................................841

X. Training Requirements and Competencies................841

Appropriate Selection of Patients ...................................841

Anatomy of the Atria and Adjacent Structures..............842

Conceptual Knowledge of Strategies to Ablate Atrial

Fibrillation..................................................................842

Technical Competence ....................................................842

Recognition, Prevention, and Management of

Complications ............................................................843

Calkins et al. Catheter and Surgical Ablation of AF 817

Appropriate Follow-up and Long-Term Management .......843

XI. Surgical Ablation of Atrial Fibrillation....................843

Development of the Cox-Maze Procedure .....................843

New Surgical Ablation Technology................................843

Surgical Atrial Fibrillation Ablation Concomitant to

Other Heart Operations .............................................844

Stand-alone Surgery for Atrial Fibrillation ....................845

Current Indications for Surgery for Stand-alone Atrial

Fibrillation..................................................................846

Surgical Ablation of Atrial Fibrillation Summary .........846

XII. Clinical Trial Considerations...................................846

Overview..........................................................................846

Investigational Studies: Current and Future ...................847

Standards for Reporting Outcomes in Clinical Trials ........848

XIII. Conclusion ..............................................................849

Table 1: Areas of Consensus: Definitions, Indications,

Technique, and Laboratory Management .................819

Table 2: Areas of Consensus: Post procedure,

Follow-up, and Clinical Trial Considerations ..........830

Figure 1............................................................................820

Figure 2............................................................................820

Figure 3............................................................................822

References........................................................................850

Disclosures.......................................................................859

During the past decade, catheter ablation of atrial fibrillation

(AF) has evolved rapidly from a highly experimental unproven

procedure, to its current status as a commonly performed

ablation procedure in many major hospitals throughout

the world. Surgical ablation of AF, using either standard

or minimally invasive techniques, is also performed in

many major hospitals throughout the world.

The purpose of this Consensus Statement is to provide a

state-of-the-art review of the field of catheter and surgical

ablation of AF, and to report the findings of a Task Force,

convened by the Heart Rhythm Society and charged with

defining the indications, techniques, and outcomes of this

procedure. The Heart Rhythm Society was pleased to develop

this Consensus Statement in partnership with the

European Heart Rhythm Association and the European Cardiac

Arrhythmia Society.

This statement summarizes the opinion of the Task Force

members based on their own experience in treating patients,

as well as a review of the literature, and is directed to all

health care professionals who are involved in the care of

patients with AF, particularly those who are undergoing or

are being considered for catheter or surgical ablation procedures

for AF. This statement is not intended to recommend

or promote catheter ablation of AF. Rather the ultimate

judgment regarding care of a particular patient must be

made by the health care provider and patient in light of all

the circumstances presented by that patient.

In writing a “consensus” document, it is recognized that

consensus does not mean that there was complete agreement

among all Task Force members. We attempted to identify

those aspects of AF ablation for which a true “consensus”

could be identified (Tables 1 and 2). Surveys of the entire

Task Force were used to identify these areas of consensus.

The main objective of this document is to improve patient

care by providing a foundation of knowledge for those

involved with catheter ablation of AF. It is recognized that

this field continues to evolve rapidly; as this document was

being prepared, further clinical trials of catheter and surgical

ablation of AF were underway.

The Task Force writing group was composed of experts

representing six organizations: the American College of

Cardiology (ACC), the American Heart Association (AHA),

the European Cardiac Arrhythmia Society (ECAS), the European

Heart Rhythm Association (EHRA), the Society of

Thoracic Surgeons (STS), and the Heart Rhythm Society

(HRS). All members of the Task Force, as well as peer

reviewers of the document, were asked to provide disclosure

statements of all relationships that might be perceived as

real or potential conflicts of interest. These tables are shown

at the end of this document.

AF is a common supraventricular arrhythmia that is characterized

by chaotic and uncoordinated contraction of the

atrium. The common electrocardiographic (ECG) manifestations

of AF include the presence of irregular fibrillatory

waves and, in patients with intact atrioventricular conduction,

the presence of an irregular ventricular response. Although

there are several classification systems for AF, for

this consensus document we have adopted the classification

system that was developed by the ACC/AHA/ESC 2006

Guidelines for the Management of Patients with Atrial Fibrillation

be used for future studies of catheter and surgical

ablation of AF.

that terminates spontaneously within seven days (Table 1).

Persistent AF is defined as AF which is sustained beyond

seven days, or lasting less than seven days but necessitating

pharmacologic or electrical cardioversion. Included within

the category of persistent AF is “longstanding persistent

AF” which is defined as continuous AF of greater than one

year duration. The term permanent AF is defined as AF in

which cardioversion has either failed or not been attempted.

The term permanent AF is not appropriate in the context of

patients undergoing catheter and/or surgical ablation of AF

as it refers to a group of patients where a decision has been

made not to pursue restoration of sinus rhythm by any

means, including catheter or surgical ablation. As noted in

the ACC/AHA/ESC 2006 Guidelines, it is recognized that a

particular patient may have AF episodes that fall into one or

more of these categories. It is recommended that patients be

categorized by their most frequent pattern of AF. These AF

definitions apply only to AF episodes which are of at least

818 Heart Rhythm, Vol 4, No 6, June 2007

30 seconds’ duration and do not have a reversible cause

such as acute pulmonary disease and hyperthyroidism.

It is recognized by the consensus Task Force that these

definitions of AF are very broad, and that when describing

a population of patients undergoing AF ablation, additional

detail should be provided. This is especially important when

considering the category of persistent AF. In particular,

investigators are urged to specify the duration of time patients

have spent in continuous AF prior to an ablation

procedure, and also to specify whether patients undergoing

AF ablation have previously failed pharmacologic therapy,

electrical cardioversion, or both.

For many years, three major schools of thought competed to

explain the mechanism(s) of AF: multiple, random propagating

wavelets; focal electrical discharges; and localized

progress has been made in defining the mechanisms of

breakthrough was the recognition that, in a subset of

patients, AF was triggered by a rapidly firing focus and

This landmark observation compelled the arrhythmia community

to refocus its attention on the pulmonary veins (PVs)

and the posterior wall of the left atrium (LA), as well as the

autonomic innervation in that region (Figure 1). It also

reinforced the concept that the development of AF requires

a “trigger” and an anatomic substrate capable of both initiation

and perpetuation of AF.

In this section of the document, a contemporary understanding

of the mechanisms of AF is summarized. As illustrated

presence of an appropriate heterogeneous AF substrate, a

focal trigger can result in sustained high frequency reentrant

AF drivers (rotors). The waves that emerge from the rotors

undergo spatially distributed fragmentation and give rise to

high frequency atrial activation is maintained for relatively

long time periods, ion channel remodeling changes the

further contributing to AF permanence. Sustained high

rates in the atrium and/or the presence of heart disease are

associated with structural remodeling of the atria and alter

Although much has been learned about the mechanisms of

AF, they remain incompletely understood. Because of this,

it is not possible to precisely tailor an ablation strategy to a

particular AF mechanism.

AF Definition

or electrical cardioversion.

patients where a decision has been made not to pursue restoration of sinus rhythm by any means, including catheter or surgical

ablation.

Indications for Catheter AF Ablation

Indications for Surgical AF Ablation

attempts at catheter ablation, or are not candidates for catheter ablation.

Pre-procedure Management

Technique and Lab Management

cavotricuspid isthmus dependent atrial flutter.

Calkins et al. Catheter and Surgical Ablation of AF 819

Until the mid to late 1980s, the multiple wavelet hypothesis

for AF was widely accepted as the dominant AF mechanism.

and subsequently confirmed by experimental

presence of multiple reentrant wavelets occurring simultaneously

in the left and right atria. According to this model,

the number of wavelets at any point in time depends on the

atrial conduction velocity, refractory period, and mass. Perpetuation

of AF is favored by slowed conduction, shortened

refractory periods, and increased atrial mass. Enhanced spatial

dispersion of refractoriness promotes reentry by conduction

block and conduction delay. It is notable that the

development of the surgical Maze procedure was predicated

on this model of AF and the concept that maintenance of AF

requires a critical number of circulating reentrant wavelets,

Haissaguerre and colleagues are credited with making the

landmark observation that AF is often triggered by a focal

source, and that ablation of that focal trigger can eliminate

manuscripts. An initial series of three patients who underwent

successful catheter ablation of AF was published in

arise from a “focal source.” The successful treatment of

these three patients with catheter ablation suggested that in

some patients, AF may result from a focal trigger and that

ablation of this trigger could eliminate AF. It is notable that

prior research in an animal model had demonstrated that AF

could be induced by local administration of aconitine which

“focal AF” also was shown to be cured by isolation of the

site of the aconitine-induced focal atrial tachycardia from

the remainder of the atria. In a subsequent report on 45

patients with frequent drug-refractory episodes of AF, Haissaguerre

and colleagues found that a purely right-sided

linear ablation approach resulted in an extremely low longterm

linear lesions were often arrhythmogenic due to gaps in the

ablative lines, and that many patients were ultimately cured

with ablation of a single rapidly firing ectopic focus. These

ectopic foci were found at the orifices of the left or right

superior PVs or near the superior vena cava. The latter

observation led these investigators to systematically attempt

cure of paroxysmal AF by mapping and ablating individual

well into the PVs, outside of the cardiac silhouette, where

of the importance of a focal trigger in the development

of AF have been confirmed by others. Thus, it is now well

which illustrates the manner in which focal triggers lead to initiation of

reentry (rotors). Eventually, atrial remodeling leads to additional focal

triggers and perpetuation of reentry.

drawing of the left and right atria as viewed from the posterior. The

extension of muscular fibers onto the PVs can be appreciated. Shown in

is the coronary sinus which is enveloped by muscular fibers which have

Marshall which travels from the coronary sinus to the region between the

mechanisms of AF. (Adapted from Circulation,13 Am J Cardiol,336 and Tex

Heart Inst J.337)

820 Heart Rhythm, Vol 4, No 6, June 2007

established that the PVs appear to be a crucial source of

triggers which initiate AF.

Nathan and Eliakim are credited with first drawing attention

to the presence of sleeves of cardiac tissue that extend onto

the PVs and also the sleeves of myocardial tissue that

extend onto the superior and inferior vena cava were studied

in animal models by investigators who noted that AF was

early observations, detailed investigation of the anatomic

and electrophysiologic properties of the PVs remained unexplored

for many decades, until the importance of PV

triggers in the development of AF was appreciated. There is

now general agreement that myocardial muscle fibers extend

from the LA into all the PVs for a length of one to three

centimeters; the thickness of the muscular sleeve is highest

at the proximal end of the veins (1–1.5 mm), and then

It is also recognized that the muscular sleeves of the PVs

are an important source of focal firing that may trigger or

maintain AF. The mechanisms of this focal firing are incompletely

understood. Whereas classical cardiac anatomists

do not feel that specialized conduction cells or tissues

are present in the PV muscular sleeves, other more recent

studies have arrived at different conclusions. It is notable

that the location of the precursors of the conduction system

are defined, during embryological development of the heart,

conduction tissue, which is derived from the heart tube and

is destined to have pacemaker activity, has been shown to be

recent study demonstrated the presence of P cells, transitional

presence of these tissues provides an explanation for the

observation that electrical activity within the PVs is commonly

observed after electrical disconnection of the PVs’

spontaneous electrical activity with phase 4 depolarization

digitalis induced triggered activity in guinea pig PV tissue

preparations with the genesis of atrial tachyarrhythmias.

More recent studies have isolated cardiomyocytes from rabbit

and canine PVs and identified the abnormal automaticity

regulation of calcium current and sodium–calcium exchanger

has been identified as the major mechanism of PV

focal arrhythmogenicity.

Other studies have provided evidence to suggest that the

PVs and the posterior LA are also a preferred site for

the electrophysiologic properties of 45 PVs from 33

dogs. Optical mapping techniques were used to study the

was shown to be longer in the endocardium of these PVs as

compared with the epicardium. In addition, these investigators

reported that the action potential duration of the PVs

was shorter than in the atrium. This study also demonstrated

marked slowing of conduction in the proximal portion of the

PV as compared with the adjacent atrial tissue. With rapid

atrial pacing, 2:1 conduction block into the veins was observed.

These findings led the authors to propose that AF

resulted from a focal trigger arising from within the PVs and

was maintained as a rapid reentrant circuit within the PVs.

A somewhat different approach was used by other authors

who used a blood perfused heart preparation to examine the

and extracellular recordings were obtained. These authors

identified zones of conduction delay in all PVs. Fractionated

signals were also found in areas of slow conduction. They

also examined PV histology and reported that these zones of

slow conduction were related to sudden changes in fiber

orientation. These changes could facilitate reentry. Yet another

study examined the impact of increasing atrial pressure

became the source of dominant rotors. These observations

help explain the clinical link between AF and increased

atrial pressure.

Several studies have reported shorter refractory period

inside PVs compared to the LA, decremental conduction

inside PVs, and easy induction of PV reentry with premature

stimulation from the PVs. And other studies have demonstrated

the presence of rapid reentrant activities with

entrainment phenomenon inside the human PVs after successful

PV isolation as well as the important role of PV–LA

ample evidence to support the understanding that PVs

and the PV–LA junction provide the reentrant substrate for

AF, the mechanism underlying the very first beat of spontaneous

PV firing which initiates AF remains poorly understood.

One study investigated the effects of ibutilide on PV

firing using a canine model of pacing-induced AF. Ibutilide

suppressed reentry at the PV–LA junction but not PV firing,

indicating that PV firing is due to a non-reentrant mechanism.

36

A number of well conducted experimental and clinical studies

have appeared over the last several years demonstrating

the importance of the local atrial activation rate (cycle

of a hierarchical organization and left-to-right gradients

mechanistic rationale for the empirical observation by clinical

electrophysiologists that the LA is the region that seems

also afford an explanation for the need for circumferential

and linear ablation, as well as other anatomic approaches

Calkins et al. Catheter and Surgical Ablation of AF 821

that not only include the PVs but also a large portion of the

LA. Inclusion of the atrial myocardium in ablation strategies

is particularly important in patients with persistent AF,

who in fact represent the vast majority of patients presenting

the arrhythmia. Recent data in patients provide compelling

evidence that the sources are in fact reentrant and are located

used power spectral analysis and mapping to localize dominant

that in paroxysmal AF patients the PV ostial region does

harbor the highest frequency sites and AF can be terminated

successfully by targeting radiofrequency (RF) ablation to

persistent AF patients it is rare to find dominant

frequency sites at the PV region and this agrees well with

the relatively poor success rate of RF ablation in such

persistent AF, atrial remodeling somehow augments the

number of AF drivers and shifts their location away from

the PV/ostial region. Therefore, while eliminating focal

triggers is sensible, evidence in the clinic and the laboratory

demonstrates that focusing on understanding mechanisms of

AF initiation, maintenance and perpetuation in the atrial

muscle proper is of outmost importance if one wants to

increase the success of therapy in the majority of patients.

It has been shown that an increase in both sympathetic and

parasympathetic tone precedes the onset of paroxysmal AF

although both sympathetic and parasympathetic components

play a role in AF, the cholinergic component appears

to be the main factor for spontaneous AF initiation in an

preparation, other authors described rapid PV triggered firing

initiated by delivering high frequency electrical stimulation

to the PV preparation during atrial refractory periods.

Such triggered firing depends on both the sympathetic and

parasympathetic components of the cardiac autonomic nervous

by AF could be induced by electrical stimulation of the

ganglionic plexi (GP) or the autonomic nerve endings that

retrogradely activate the GP and initiate AF from the

evidence that the intrinsic cardiac autonomic nervous

system facilitates the formation of triggered PV firing

that either initiates AF or initiates reentry, which subsequently

induces AF.

It is well accepted that the development of AF requires

both a trigger and a susceptible substrate. The goals of

AF ablation procedures are to prevent AF by either eliminating

the trigger that initiates AF or by altering the

arrhythmogenic substrate. The most commonly employed

ablation strategy today, which involves the electrical

isolation of the PVs by creation of circumferential lesions

around the right and the left PV ostia, probably impacts

particular, this approach seeks to electrically isolate the

PVs, which are the most common site of triggers for AF.

Other less common trigger sites for AF, including the

vein and ligament of Marshall and the posterior LA wall,

are also encompassed by this lesion set. The circumferential

lesions may also alter the arrhythmogenic substrate

by elimination of tissue located near the atrial–PV junction

that provides a substrate for reentrant circuits that

may generate or perpetuate AF, and/or by reduction of

finally, the circumferential lesion set may interrupt sympathetic

and parasympathetic innervation from the auto-

Circumferential ablation lesions, which are created in a circumferential

fashion around the right and the left PVs. The primary endpoint of this

of the most common sites of linear ablation lesions. These include a “roof

line” connecting the lesions encircling the left and and/or right PVs, a

“mitral isthmus” line connecting the mitral valve and the lesion encircling

the left PVs at the level of the left inferior PV, and an anterior linear lesion

connecting the either the “roof line” or the left or right circumferential

lesion to the mitral annulus anteriorly. Also shown is a linear lesion created

at the cavotricuspid isthmus. This lesion is generally placed in patients who

have experienced cavotricuspid isthmus dependent atrial flutter clinically

addition of additional linear ablation lesions between the superior and

inferior PVs resulting in a figure of 8 lesion set. Also shown is an encircling

lesion of the superior vena cava directed at electrical isolation of the

superior vena cava. SVC isolation is performed if focal firing from the SVC

Some of the most common sites of ablation lesions when complex fractionated

electrograms are targeted. (Adapted from Circulation,21 Am J

Cardiol,352 and Tex Heart Inst J.353)

822 Heart Rhythm, Vol 4, No 6, June 2007

nomic ganglia, which have been identified as potential

There are several hypothetical reasons to perform ablation

procedures for treatment of AF. These include improvement

in quality of life, decreased stroke risk, decreased heart

failure risk, and improved survival. In this section of the

document, these issues will be explored in more detail.

However, it is important to recognize that the primary justification

for an AF ablation procedure at this time is the

presence of symptomatic AF, with a goal of improving a

patient’s quality of life. Although each of the other reasons

to perform AF ablation identified above may be correct,

they have not been systematically evaluated as part of a

large randomized clinical trial and are therefore unproven.

Several epidemiologic studies have shown strong associations

between AF and increased risk of cerebral thromboembolism,

development of heart failure, and increased

abnormalities including a decrease in stroke volume,

increased LA pressure and volume, shortened diastolic ventricular

filling period, AV valvular regurgitation, and an

AF leads to anatomic and electrical remodeling of the LA

that may facilitate persistence of AF. Most importantly,

many patients, even those with good rate control, experience

intolerable symptoms during AF.

There have been multiple randomized clinical trials performed

that address the question of whether rhythm control

is more beneficial than rate control for AF patients. In all

trials, antiarrhythmic drugs were used for rhythm control.

The Pharmacological Intervention in Atrial Fibrillation

(PIAF) trial first demonstrated that rate control was not

inferior to rhythm control in the improvement of symptoms

(STAF) trial showed no significant difference in the primary

endpoints of death, systemic emboli and cardiopulmonary

study demonstrated an improvement in quality of life and

exercise performance at 12 months’ follow-up in a series of

up Investigation of Rhythm Management (AFFIRM)

trial, in which 4,060 AF patients with high risk for stroke

and death were randomized to either rhythm control or rate

control, there were no significant differences in all-cause

analysis of the AFFIRM study revealed that the

presence of sinus rhythm was associated with a significant

reduction in mortality, whereas the use of antiarrhythmic

beneficial effect of sinus rhythm restoration on survival

might be offset by the adverse effects of antiarrhythmic

drugs. Previously, the Danish Investigations of Arrhythmia

and Mortality on Dofetilide (DIAMOND) study also

showed the presence of sinus rhythm was associated with

was a retrospective analysis, and the improvement in survival

may have resulted from factors other than the presence

of sinus rhythm.

These clinical trials clearly show that the strategy of

using antiarrhythmic drugs to maintain sinus rhythm does

not achieve the potential goals of sinus rhythm mentioned

above. However, there are signals in these data to suggest

that sinus rhythm may be preferred over rate control if it

could be achieved by a method other than drug therapy.

Pappone et al compared the efficacy and safety of circumferential

PV ablation with antiarrhythmic drug treatment in

a large number of patients with long-term follow-up, and

showed that ablation therapy significantly improved the

not a prospective randomized study, these findings must be

considered preliminary. Three recent small randomized trials

in patients with paroxysmal AF demonstrated that catheter

ablation was superior to antiarrhythmic therapy in the

retrospective study suggests that some patients with successful

ablation may not require long-term anticoagulation.

to sinus rhythm obtained by ablation techniques over rate

control. However, large prospective multicenter randomized

clinical trials will be needed to definitively determine

whether sinus rhythm achieved with ablation techniques

lowers morbidity and mortality as compared with rate control

alone or treatment with antiarrhythmic therapy.

The ACC/AHA/ESC 2006 Guidelines for the Management

of Patients with Atrial Fibrillation, written in collaboration

with the Heart Rhythm Society, state that “Catheter ablation

is a reasonable alternative to pharmacological therapy to

prevent recurrent AF in symptomatic patients with little or

no LA enlargement” (Class 2A recommendation, level of

in this section of the document states that treatment of

precipitating or reversible causes of AF is recommended

before initiating antiarrhythmic drug therapy. Further, the

maintenance of sinus rhythm treatment algorithm lists catheter

ablation as second-line therapy for all categories of

The Task Force supports these recommendations. In

particular, the Task Force agrees that catheter ablation of

AF in general should not be considered as first line

therapy. There is a consensus among the Task Force that

the primary indication for catheter AF ablation is the

presence of symptomatic AF refractory or intolerant to at

least one Class 1 or 3 antiarrhythmic medication (Table

1). The Task Force also recognizes that in rare clinical

situations, it may be appropriate to perform catheter

ablation of AF as first line therapy. Catheter ablation of

AF is also appropriate in selected symptomatic patients

Calkins et al. Catheter and Surgical Ablation of AF 823

with heart failure and/or reduced ejection fraction. The

presence of a LA thrombus is a contraindication to catheter

ablation of AF. It is important to recognize that

catheter ablation of AF is a demanding technical procedure

that may result in complications. Patients should

only undergo AF ablation after carefully weighing the

risks and benefits of the procedure.

As demonstrated in a large number of published studies,

the primary clinical benefit from catheter ablation of AF

is an improvement in quality of life resulting from elimination

of arrhythmia-related symptoms such as palpitations,

fatigue, or effort intolerance (see section on Outcomes

and Efficacy of Catheter Ablation of Atrial

Fibrillation). Thus, the primary selection criterion for

catheter ablation should be the presence of symptomatic

AF refractory or intolerant to at least one Class 1 or 3

antiarrhythmic medication.

Other considerations in patient selection include age, LA

diameter, and duration of AF. The heightened risk of myocardial

perforation and thromboembolic complications in

very elderly patients, and the lower probability of a successful

outcome when the LA is markedly dilated should be

taken into account when considering ablation. Furthermore,

catheter ablation of AF is less likely to be successful when

used in the treatment of patients with longstanding persistent

AF (see section on Outcomes and Efficacy of Catheter

Ablation of Atrial Fibrillation).

In clinical practice, many patients with AF may be

asymptomatic but seek catheter ablation as an alternative to

long-term anticoagulation with warfarin. Although one

study demonstrated that discontinuation of warfarin therapy

after catheter ablation may be safe over medium-term follow-

up in some subsets of patients, this has never been

confirmed by a large prospective randomized clinical trial

recognized that symptomatic and/or asymptomatic AF may

recur during long-term follow-up after an AF ablation procedure.

recommends that discontinuation of warfarin therapy post

ablation is generally not recommended in patients who have

a congestive heart failure, history of high blood pressure,

age (75 years) diabetes, prior stroke or transient ischemic

appropriate for patients with a CHADS score of 1 following

an ablation procedure. A patient’s desire to eliminate the

need for long-term anticoagulation by itself should not be

considered an appropriate selection criterion. In arriving at

this recommendation, the Task Force recognizes that patients

who have undergone catheter ablation of AF represent

a new and previously unstudied population of patients.

Clinical trials are therefore needed to define the stroke risk

of this patient population and to determine whether the risk

factors identified in the CHADS or other scoring systems

apply to these patients.

Cox and colleagues are credited with developing and demonstrating

surgeons evaluated the efficacy of surgical approaches

final iteration of the procedure developed by Cox, which is

referred to as the Maze-III procedure, was based on a model

of AF in which maintenance of the arrhythmia was shown to

require maintenance of a critical number of circulating

wavelets of reentry. The success of the Maze-III procedure

in the early 1990s led some interventional cardiac electrophysiologists

to attempt to reproduce the procedure with RF

catheter lesions using a transvenous approach. Swartz and

colleagues reported recreation of the Maze-I lesion set in a

small series of patients using specially designed sheaths and

the complication rate was high, and the procedure and

fluoroscopy times were long in their early experience, this

report demonstrated a proof of concept that led others to try

to improve the catheter based procedure. Although a large

number of investigators attempted to replicate the surgical

MAZE procedure through the use of either three-dimensional

(3D) mapping systems or the use of multipolar ablation

electrode catheters, these clinical trials had limited

advances in ablation of AF targeting initiating focal triggers,

electrophysiologists lost interest in catheter based linear

ablation for AF ablation.

The identification of triggers that initiate AF within the PVs

led to prevention of AF recurrence by catheter ablation at

of the triggers was limited by the infrequency with

which AF initiation could be reproducibly triggered during

a catheter ablation procedure. A further limitation of this

approach is that multiple sites of triggering foci were commonly

observed.

To overcome these limitations, an ablation approach was

designed to electrically isolate the PV myocardium. This

segmental PV isolation technique involved the sequential

identification and ablation of the PV ostium close to the

earliest sites of activation of the PV musculature. This

typically involved the delivery of RF energy to 30% to 80%

of the circumference of the PVs. The endpoint of this

procedure was the electrical isolation of at least three PVs.

An anatomically based ablation strategy of encircling the

PVs guided by 3D electroanatomical mapping was subsequently

The recognition of PV stenosis as a complication of RF

delivery within a PV, as well as the recognition that sites of

AF initiation and/or maintenance were frequently located

824 Heart Rhythm, Vol 4, No 6, June 2007

within the PV antrum, resulted in a shift in ablation strategies

to target the atrial tissue located in the antrum rather

positioned close to the PV ostium, or by a continuous

circumferential ablation lesion created to surround the

either each ipsilateral PV separately or both ipsilateral

PVs together (Figure 3). The circumferential ablation/isolation

line was either guided by 3D electroanatomical mapping,

(or dissociation) of the PV potentials recorded from either

one or two circular mapping catheters or a basket catheter

Although ablation strategies, which target the PVs, remain

the cornerstone of AF ablation procedures for both

paroxysmal and persistent AF, continued efforts are underway

to identify additive strategies to improve outcome. One

of these strategies is to create additional linear lesions in the

LA similar to those advocated with the Cox Maze-III, the

common sites are the LA “roof” connecting the superior

aspects of the left and right upper PV isolation lesions, the

region of tissue between the mitral valve and the left inferior

PV (the mitral isthmus), and anteriorly between the roof line

near the left or right circumferential lesion and the mitral

is recommended by the Task Force in patients with a history

of typical atrial flutter or inducible cavotricuspid isthmus

Non-PV triggers initiating AF can be identified in up to

one third of unselected patients referred for catheter

tachycardias such as AV nodal reentry or accessory pathway

mediated atrioventricular reciprocating tachycardia

may also be identified in up to 4% of unselected patients

referred for AF ablation and may serve as a triggering

in patients with both paroxysmal and more persistent

the non-PV triggers has resulted in elimination of

include the posterior wall of the LA, the superior vena

cava, crista terminalis, the fossa ovalis, the coronary

sinus, behind the Eustachian ridge, along the ligament of

Marshall, and adjacent to the AV valve annuli (Figure

Provocative maneuvers such as the administration of isoproterenol

in incremental doses of up to 20 g/min,

and/or cardioversion of induced and spontaneous AF, can

aid in the identification of PV and non-PV triggers. Linear

LA lesions not aiming at PV isolation have been

demonstrated to successfully prevent AF recurrences as

Areas with complex fractionated atrial electrograms

(CFAE) have been reported to potentially represent AF

substrate sites and became target sites for AF ablation.

ms). CFAEs usually are low-voltage multiple potential signals

between 0.06 and 0.25 mV. The primary endpoints

during RF ablation of AF using this approach are either

complete elimination of the areas with CFAEs, conversion

of AF to sinus rhythm (either directly or first to an atrial

tachycardia), and/or noninducibility of AF. For patients

with paroxysmal AF, the endpoint of the ablation procedure

using this approach is noninducibility of AF. For patients

with persistent AF, the endpoint of ablation with this approach

is AF termination. When the areas with CFAEs are

completely eliminated, but the arrhythmias continue as organized

atrial flutter or atrial tachycardia, the atrial tachyarrhythmias

are mapped and ablated.

A tailored approach to catheter ablation of AF targets

specific drivers of AF and seeks to eliminate AF using the

the mechanisms of AF may vary from patient to patient,

an individualized, electrogram-based approach is used

instead of a standardized, predetermined lesion set. If the

most rapid electrical activity is within the PVs, the PVs

are isolated. PV isolation is then followed by CFAE

ablation or serial creation of linear lesions. In contrast, if

the PVs exhibit a slow, well organized rhythm, non-PV

sites are targeted including CFAE ablation. The endpoint

of these procedures in patients with paroxysmal AF is the

inability to induce AF. In patients with longstanding

persistent AF, a step-wise approach to ablation has been

reported to successfully convert AF to either sinus

but an endpoint of noninducibility of AF does not appear

Adding GP to other ablation targets may improve ablation

inferior left GP, anterior right GP, and inferior right GP) are

located in epicardial fat pads at the border of the PV antrum,

and can be localized at the time of ablation using endocardial

high frequency stimulation (HFS) (Figure 1). For ablation,

RF current can be applied endocardially at each site of

positive vagal response to HFS. HFS is repeated and additional

RF applications can be applied until the vagal response

to HFS is eliminated.

Shown in Table 1 are the areas of consensus on ablation

techniques that were identified by the Task Force. The Task

Force recommends that:

Calkins et al. Catheter and Surgical Ablation of AF 825

1. Ablation strategies which target the PVs and/or PV antrum

are the cornerstone for most AF ablation procedures.

2. If the PVs are targeted, complete electrical isolation

should be the goal.

3. Careful identification of the PV ostia is mandatory to

avoid ablation within the PVs.

4. If a focal trigger is identified outside a PV at the time of

an AF ablation procedure, it should be targeted, if possible.

5. If additional linear lesions are applied, line completeness

should be demonstrated by mapping or pacing maneuvers.

6. Ablation of the cavotricuspid isthmus is recommended

only in patients with a history of typical atrial flutter or

inducible cavotricuspid isthmus dependent atrial flutter.

7. If patients with longstanding persistent AF are approached,

ostial PV isolation alone may not be sufficient.

The presumed basis of successful AF ablation is production

of myocardial lesions that block the propagation of AF

wave fronts from a rapidly firing triggering source, or modification

of the arrhythmogenic substrate responsible for

reentry. Successful ablation depends upon achieving lesions

employed by cardiac electrophysiologists to reach

the goal of AF ablation is RF energy delivery by way of a

transvenous electrode catheter.

RF energy achieves myocardial ablation by the conduction

of alternating electrical current through myocardial

tissue, a resistive medium. The tissue resistivity results in

dissipation of RF energy as heat, and the heat then conducts

passively to deeper tissue layers. Most tissues exposed to

temperatures of 50°C or higher for more than several seconds

will show irreversible coagulation necrosis, and evolve

and good electrode–tissue contact promote the formation

of larger lesions and improve procedure efficacy. High

power delivery can be achieved with large-tip or cooled-tip

by a combination of steerable catheter selection, guide

sheath manipulation, and skill of the operator. Significant

complications can occur during AF ablation if high RF

power is administered in an uncontrolled fashion. The increased

risk of AF ablation compared to ablation of other

arrhythmias may be attributable to the great surface area of

tissue ablated, the large cumulative energy delivery, the risk

of systemic thromboembolism, and the close location of

structures susceptible to collateral injury, such as phrenic

be minimized by limiting power and/or target temperature,

Intramural steam pops can be reduced by limiting power

and the electrode–tissue contact pressure, which is greater

when the catheter is oriented perpendicular to the atrial wall.

Early reports of catheter ablation of AF employed conventional

4-mm or 5-mm tip ablation catheters. Lesions

were created with point-to-point application of RF energy or

with continuous RF energy application while the catheter

was dragged across the myocardium. It was observed clinically

and experimentally that this approach resulted in

multiple sites of non-transmural lesion formation. The majority

of the members of the Task Force now employ irrigated

tip catheters. Although comparative trials of irrigated

tip and large tip RF technologies versus conventional RF

electrodes have demonstrated increased efficacy and decreased

procedure duration in the ablation of atrial flutter,

catheters have not been performed in patients undergoing

AF ablation. Therefore, we are unable to make a firm

recommendation regarding the optimal RF energy delivery

system and catheter.

Various techniques have been proposed to minimize collateral

injury. Temperature sensors at the electrode catheter

tip can provide gross feedback of surface temperature, but

because of passive convective cooling from circulating

blood flow, or active cooling in a cooled tip catheter, the

peak tissue temperatures are sometimes millimeters below

the endocardial surface. Depending upon the ablation technology

employed many operators limit RF power to 25–35

watts. Limiting power will limit collateral injury but at the

expense of reliably transmural lesions. ICE has been employed

to monitor lesion formation. If the tissue shows

evidence of increased echogenicity, or if small gas bubbles

are observed, then power should be reduced or terminated.

RF catheter ablation is approximately 60–90 seconds.

smaller ablative lesions. Monitoring unipolar electrogram

amplitude has been proposed by W.M. Jackman, MD (via

personal communication) as an assay of lesion transmurality.

Although RF energy is most commonly employed for catheter

ablation of AF, a number of alternative catheter ablation

systems that utilize different ablative energy sources have

been developed and currently are being evaluated in clinical

trials. These include cryoablation, ultrasound ablation, and

be performed with a conventional “tip” catheter, a circular

catheter, or a balloon device. For the remainder of these

alternative energy sources, a balloon system is available

which is typically positioned at the PV ostium either directly

by steering the shaft, using a steerable sheath, or

using an “over-the-wire” technique. Subsequently, energy is

delivered to achieve a full circumferential or sector ablation.

The primary endpoint for all new energy sources is PV

isolation.

826 Heart Rhythm, Vol 4, No 6, June 2007

Multielectrode circumferential mapping catheters have been

developed by several manufacturers to facilitate catheter

catheters (10 to 20 electrodes) are positioned either at the

ostium of the PVs or moved around the PV antrum and

simultaneously record electrical potentials from the muscular

sleeves of the PVs, referred to as PV potentials. These

circular electrode catheters are deflectable and are available

in either a fixed or variable diameter. This type of electrode

catheter is currently used by many centers to verify electrical

Catheter ablation of AF is currently being performed in

most centers using 3D mapping systems, which allow for

nonfluoroscopic catheter manipulation, activation and voltage

mapping, and precise identification and tagging of ablation

sites to facilitate creation of contiguous lesions

around anatomic structures such as the PVs and to also

facilitate creation of linear lesions. The two most widely

used systems are the CARTO (Biosense Webster, Diamond

Position Management System and Loca Lisa also provide

systems has been demonstrated to reduce fluoroscopy duration.

mapping systems is the ability to register pre-acquired MR/CT

images to the real time mapping space during AF ablation

several potential sources of error, which may influence the

accuracy of the registration process, including differences in

the volume status, respiratory phase between the CT/MR image

and the electroanatomic map, cardiac rhythm differences,

as well as the registration algorithm.

At this present time, it appears that each of the systems

currently available can be used to facilitate AF ablation

procedures. To date (at publication), there have been no

head-to-head randomized comparisons of these systems.

Catheter based ablation of AF places significant demands

on the skill and experience of the electrophysiologist.

The objectives of developing new technologies to facilitate

these procedures include precise and stable catheter

navigation, reduced radiation exposure, shorter procedures,

and cost effectiveness. While new technologies

generally increase the cost of a procedure when they are

introduced, the costs may be justified if they improve

outcomes. The concept of remote catheter navigation is

appealing for the operator because these systems may

reduce radiation exposure to the physician and also the

risk of developing orthopedic problems related to prolonged

use of protective lead aprons. The two technologies

developed to meet these objectives include the

magnetic navigation system designed by Stereotaxis,

FDA-approved specifically for ablation of AF at this

point, the impetus to develop these technologies is to use

them for complex ablation procedures. The potential utility

of these remote navigation systems will need to be

determined. At the present time, studies are not available

to demonstrate that either of these systems shortens procedure

time, improves outcomes of ablation, or improves

the safety profile of these and other complex ablation

procedures.

Historically, electrophysiologists have predominantly used

fluoroscopy as the imaging method during invasive procedures.

However, fluoroscopy is unable to identify key anatomic

locations such as the fossa ovalis, the PVs, the LA

appendage, the valve apparatus, and extracardiac structures,

which are relevant during ablative procedures for AF. ICE

is able to provide real time anatomic information without

the drawbacks of transesophageal echocardiography (TEE),

which is limited by the patient discomfort and the need for

A survey taken by the members of this Task Force revealed

that approximately 50% of centers routinely used ICE to

facilitate the transseptal procedure and/or to guide catheter

ablation. The two available ICE systems consist of mechanical/

rotational and phased-array transducers. Mechanical

transducers produce high quality images at shallow depths.

Therefore, they need to be advanced in the LA to visualize

LA structures. In contrast, a phased-array system uses a 64

piezoelectric element linear transducer operating at frequency

from 5.5 and 10 MHz, and it provides high resolution

2D images with a penetration ranging from 2 mm to 12

cm. This allows imaging of the LA with the ICE probe

placed in the right atrium. ICE provides direct and real time

imaging of structures relevant to the ablation procedure. It

facilitates the transseptal puncture especially in the presence

of anatomic variants or specific clinical conditions such as

large septal aneurysm, lipomatous hypertrophy of the septum,

previous cardiac surgery with distorted anatomy or

thickened septum, or prior surgical or device closure of an

atrial septal defect. Therefore, the implementation of ICE

may decrease the risk of complications associated with the

transseptal access. Once in the LA, the success of the

procedure depends on the ability to properly position mapping

and ablation catheters. ICE can help the operator in

visualizing the PV anatomy, catheter– cardiac tissue interface,

catheter placement, and can also be used for identification

of thrombus formation. In addition, ICE may help

optimize RF energy delivery by detecting microbubbles,

which represent tissue superheating. ICE can also be valuable

in prompt detection and treatment of complications.

Important drawbacks of the technique are the need for an

additional sheath for placement of the catheter, cost, and the

lack of 3D imaging.

Calkins et al. Catheter and Surgical Ablation of AF 827

PV venography is performed by many centers at the time of

venography is to help guide catheter manipulation, determine

the size and location of the PV ostia, and also assess

PV stenosis, particularly among patients undergoing repeat

ablation procedures. A survey of the members of this Task

Force revealed that 50% of centers routinely employed PV

venography during their AF ablation procedures. There are

three techniques that have been described for PV venography.

The first is performed by injection of contrast medium

into the left and right pulmonary arteries or the pulmonary

trunk. The location of the PVs can then be assessed during

the venous phase of pulmonary arterography. The second

technique involves the injection of contrast media in the

body of the LA or at the roof of the right or left superior PV

ostium immediately after delivery of a bolus of adenosine to

induce AV block. The contrast media will fill the LA body,

PV antrum and the proximal part of PV during the phase of

ventricular asystole. Moreover, the third technique involves

selective delivery of contrast media into each of the PV

ostia. This can be accomplished by positioning the transseptal

sheath in the region of the right and left PV trunks

and injecting contrast, or by selectively engaging each of the

four PV ostia using a deflectable catheter or a multipurpose

angiography catheter.

Understanding the morphological characteristics of the LA

in detail can not only help achieve a more efficient and

successful ablation but also may prevent procedure-related

complications. CT/MR may facilitate AF ablation procedures

by:

1. imaging the anatomic features of the PVs and LA preprocedurally

2. disclosing the anatomic relationship between the LA,

esophagus and adjacent vascular structures

3. providing an understanding of the degree of morphological

remodeling of the PVs and LA, and

4. assisting in the detection of post procedure complications.

As will be discussed in the complications section of the

document, CT and MR are excellent tools for detection of

PV stenosis. A survey given to the Task Force members

revealed that approximately two thirds of centers are routinely

obtaining MR or CT scans in patients scheduled to

have an AF ablation.

The PV ostia are ellipsoid with a longer superio-inferior

dimension, and the funnel-shaped ostia are frequently noted

to the superior vena cava or right atrium, and the right

inferior PV projects horizontally. The left superior PV is in

close vicinity to LA appendage and the left inferior PV

courses near the descending aorta. Veins are larger in AF

versus non-AF patients, men versus women, and persistent

versus paroxysmal patterns. The understanding of these

anatomic relationships is essential for accomplishing safe

transseptal puncture, placement of a circular mapping catheter

and application of energy around or outside the PV

ostia. The variability of PV morphologies can substantially

influence the success rate of catheter ablation if the variant

veins are inadequately treated. Several studies reported the

existence of supernumerary right PVs with the incidence

longer distance between the PV ostium and first

branch was demonstrated for left versus right PVs. One

study showed that multiple ramifications and early branching

were observed in right inferior PVs, possibly accounting

A common trunk of left or right PVs also has been disclosed

ostium is more frequently found on the left-sided PVs (6%–

recently, 3D reconstruction of CT and MR and intracardiac

echo imaging have shown a common ostium in both right

variations are important in planning catheter ablation of AF.

Localization of the true PV–LA, the LA appendage, and the

ridge between PV and LA appendage in these patients can

be more accurate with the assistance of the 3D images

As described above, currently available electroanatomic

mapping systems allow previously acquired CT or MR

images to be imported into the mapping systems and registered

with the LA real time. These systems help facilitate

AF ablation procedures by providing detailed information

critical to confirm accurate registration.

Careful attention to anticoagulation of patients before, during,

and after ablation for AF is critical to avoid the occurrence

of a thromboembolic event, which is recognized as

one of the most serious complications of AF and also of AF

ablation procedures. Anticoagulation, in turn, contributes to

some of the most common complications of the procedure,

including hemopericardium/pericardial tamponade and vascular

achieving the optimal safe level of anticoagulation throughout

the process.

As is the case with all patients with AF, patients undergoing

ablation therapy are at risk for LA thrombus formation

this reason that the Task Force recommends that the anticoagulation

guidelines published as part of the ACC/AHA/

ESC 2006 Guidelines for the Management of Patients with

for anticoagulation, both for long-term management

and also those that apply to cardioversion procedures,

should be followed. It is particularly important to recognize

that the recommendations for anticoagulation at the time of

828 Heart Rhythm, Vol 4, No 6, June 2007

cardioversion apply to patients who are in AF at the time of

the ablation procedure and in whom AF termination is

sought during an AF ablation procedure, either by catheter

ablation or by cardioversion. Not only are these patients

expected to achieve restoration of sinus rhythm, either by

electrical or pharmacologic cardioversion or by successful

arrhythmia termination with ablation, but also the ablation

procedure leaves patients with substantial areas of damaged

LA endothelium that may become a nidus for thrombus

formation. In addition to following these anticoagulation

guidelines, there is a consensus among the Task Force that

patients with persistent AF who are in AF at the time of

ablation should have a TEE performed to screen for a

thrombus (Table 1) regardless of whether they have been

anticoagulated with warfarin prior to ablation. This reflects

the fact that an ablation catheter will be manipulated

throughout the LA during an AF procedure and that dislodgement

complication. Recently, 64-slice CT scanning

remains the gold standard. Exclusion of LA thrombus with

preprocedure imaging is most important in patients with

significant atrial enlargement, particularly if risk factors for

stroke are present. The yield of LA thrombus identification

with TEE among patients with paroxysmal AF who are in

sinus rhythm at the time of ablation is very low, particularly

in patients without structural heart disease or risk factors for

stroke. Some Task Force members do not routinely perform

pre-procedure screening with TEE in this setting. In addition

to performing a TEE to screen for a LA thrombus in

patients with persistent AF who are in AF at the time of

ablation, some Task Force members recommend 0.5–1

mg/kg of enoxaparin twice daily until the evening prior to

the ablation procedure for patients who have been anticoagulated

with warfarin.

The ablation of AF is associated with placement of 1–3

catheters in the LA via transseptal puncture. The catheter

manipulation time in this chamber can be prolonged. There

is a prolonged dwell time in this chamber. Thus, heparin

anticoagulation with close attention to maintaining therapeutic

dosing during the procedure is important. Because

thrombi can form on the transseptal sheath almost immediately

after crossing the septum, many operators administer a

loading dose of heparin prior to or immediately upon septal

puncture. After a loading dose of 100 U/kg, a standard

heparin infusion of 10 U/kg/hour can be initiated. Activated

clotting times (ACT) should be checked at 10- to 15-minute

intervals until therapeutic anticoagulation is achieved and

then at 30 minute intervals during the case. The lower level

of anticoagulation should be maintained at an ACT of at

least 300–350 seconds throughout the procedure, as it has

been demonstrated that less intense anticoagulation is associated

also may be reduced by infusing heparinized saline continuously

atrial enlargement or spontaneous echo contrast is observed,

many operators target a higher ACT range of 350–400

seconds. The risk of systemic embolization of thrombus

formed on a sheath may be reduced by withdrawing the

sheath to the right atrium once a catheter is positioned in the

LA. Single catheter techniques may also reduce this risk. In

order to reduce bleeding complications, antiplatelet therapy

(especially IIB/IIIA glycoprotein receptor blockers and clopidogrel)

should be avoided if possible. At the conclusion of

the procedure, sheath removal requires withdrawal of anticoagulation

for a window of time to achieve adequate hemostasis.

Heparin infusion can be discontinued and the

sheaths removed from the groin when the ACT is less than

200 seconds. Alternatively, some operators choose to reverse

heparin with protamine. If protamine is employed,

care must be taken to avoid this drug in patients who have

received NPH insulin, or have a fish allergy since they may

be sensitized to protamine and be at risk for an anaphylactic

After catheter ablation and sheath removal, anticoagulation

should be reinitiated promptly (within four to six

hours). Operators administer therapeutic loading doses of

heparin or subcutaneous enoxaparin. Warfarin is readministered

post ablation, and heparin or enoxaparin are continued

until a therapeutic INR is achieved. Many of the members

of this Task Force empirically and independently

arrived at a dose of 0.5 mg/kg twice daily for enoxaparin,

since an unacceptable incidence of bleeding complications

has been observed at a dose of 1.0 mg/kg BID. There was a

consensus among the Task Force that:

1. Warfarin is recommended for all patients for at least two

months following an AF ablation procedure,

2. Decisions regarding the use of warfarin more than two

months following ablation should be based on the patient’s

risk factors for stroke and not on the presence or

type of AF.

3. Discontinuation of warfarin therapy post ablation is generally

not recommended in patients who have a CHADS

The consensus Task Force acknowledges that the twomonth

recommendation for warfarin post ablation regardless

of their CHADS score is empirical and that practice

patterns may vary, particularly in patients with paroxysmal

AF who are at low risk for stroke, and who are in sinus

rhythm at the time of their AF ablation procedure. A small

number of operators have chosen an alternate approach to

procedural anticoagulation by initiating warfarin therapy

pre-procedure and continuing this drug in a therapeutic

range during the procedure. The obvious benefits of this

approach are that the patient is never without therapeutic

anticoagulation before or after the procedure, and some of

the vascular complications that are exacerbated by the combination

of enoxaparin and warfarin may be avoided. The

concern about this approach is that acute bleeding complications,

particularly pericardial tamponade, may be more

Calkins et al. Catheter and Surgical Ablation of AF 829

difficult to control if anticoagulation cannot be immediately

reversed in that setting.

Limited data are available regarding the risk of thromboembolism

with and without warfarin after AF ablation.

The long-term follow-up of patients undergoing the surgical

Maze procedure has shown a very low risk of stroke in this

patients in that study were lost to follow-up. Importantly, an

essential component of the Maze procedure is amputation of

the LA appendage, the putative source of most LA thrombi.

Intermediate-term follow-up of a population of 755 patients

has shown that stroke risk after catheter ablation is comparable

Most events occurred within two weeks of the procedure,

and both patients with late stroke were therapeutically anticoagulated

at the time of stroke presentation. In this study,

73% of patients in apparent sinus rhythm post-procedure

discontinued warfarin after 3 months. Although this study

suggests that discontinuation of warfarin therapy after catheter

ablation may be safe over medium-term follow-up in

some subsets of patients, this has never been confirmed by

a large prospective randomized trial and therefore remains

symptomatic or asymptomatic AF may recur during longterm

that patients may have fewer symptoms during ongoing AF

this Task Force recommends, as noted above, that discontinuation

of warfarin therapy post-ablation generally is not

recommended in patients who have a CHADS2 score

Patients undergoing catheter ablation of AF are required to

lie motionless on the procedure table for three or more

hours. Repeated stimuli from ablation of the thin-walled

atrium, often in close vicinity to regions of autonomic innervation

and/or the esophagus, are sometimes quite painful.

For these reasons, most patients are treated with conscious

sedation or general anesthesia. The choice of

Post-procedure Management

following AF ablation.

stroke and not on the presence or type of AF.

Follow-up and Clinical Trial Considerations

represent true benefit.

secondary endpoint of ablation.

more.

at least two years.

follow-up.

ECG monitoring performed to screen for asymptomatic AF/flutter/tachycardia.

at three to six months intervals for one to two years following ablation.

with medical therapy.

require hospitalization.

830 Heart Rhythm, Vol 4, No 6, June 2007

approach is determined by the institutional preference and

also by assessment of the patient’s suitability for conscious

sedation. General anesthesia is generally employed for patients

at risk of airway obstruction, those with a history of

sleep apnea, and also those at increased risk of pulmonary

edema. General anesthesia may also be employed electively

in healthy patients in order to improve patient tolerance of

the procedure. Anesthesia or analgesia needs to be administered

by well-trained and experienced individuals with

monitoring of heart rate, non-invasive or arterial line blood

levels of anesthesia and training requirements for administration

of intravenous sedation during procedures have been

developed by the American Society of Anesthesiologists

Force members of this consensus statement revealed that

approximately two thirds of centers use conscious sedation

for AF ablation procedures, and reserve general anesthesia

support for high-risk patients.

A rare but potentially devastating complication of AF ablation

is injury to the esophagus with the possible outcome

of atrial esophageal fistula or esophageal perforation leading

information concerning the incidence, presentation, and

management of this complication is presented under the

complications section of this document. Because of the

severe consequence of an atrial esophageal fistula, it is

important to attempt to avoid this complication. At the

present time, a number of different approaches are being

employed to avoid the development of an atrial esophageal

fistula. The most common practice is to decrease power

delivery, decrease tissue contact pressure, and move the

ablation catheter every 10 to 20 seconds when in close

proximity to the esophagus. Some operators employ light

conscious sedation and use pain as an assay for potential

esophageal injury. A variety of approaches have been proposed

to identify esophageal anatomic location, including

tagging of the esophageal position with an electroanatomical

centers, it is important to note that, owing to the rarity of

this complication, it remains unproven whether their use

lowers or eliminates the risk of esophageal perforation.

Pre-procedure computerized tomography or magnetic resonance

imaging is valuable; however, motion of the esophagus

during the procedure (particularly in patients under

lighter sedation) can result in discordance between the preprocedure

tagging of the esophageal location is static unless an electrode

remains in the esophagus during the case. Temperature

monitoring is useful to identify potentially dangerous

heating of the esophagus. However, since the esophagus is

broad, the lateral position of the temperature probe or mapping

electrode may not align with the ablation electrode, and

the operator may have a false impression of safety. Although

there is general agreement among those operators

who employ temperature probes that an increase in esophageal

temperature should trigger interruption of RF energy

delivery, there is no consensus as to what degree of temperature

elevation should trigger RF termination. Barium

paste swallowed by the patient prior to conscious sedation

Because the barium paste remains in the esophagus for the

duration of the procedure, this approach allows for a real

time assessment of the relationship of the location of the

ablation catheter and the esophagus. The risk of this technique

is barium aspiration if the patient becomes overly

sedated and does not have airway protection with endotracheal

intubation. ICE allows real time visualization of the

adjunctive tool have reported it to be of value in monitoring

the location of the esophagus relative to the ablation catheter.

esophagus has not yet been determined, and awaits ongoing

prospective evaluation of these approaches.

Arrhythmia monitoring is an important component of the

initial evaluation of patients who are to undergo catheter

ablation procedures for AF. Prior to undergoing a catheter

ablation procedure, it is important to confirm that a patient’s

symptoms result from AF and to determine whether a patient

has paroxysmal or persistent AF. This is of importance

as the ablation technique, procedure outcome, anticoagulation

strategies employed, and the need for TEE prior to the

procedure may be impacted by the accurate characterization

of the AF type and burden. An assessment of the adequacy

of heart rate control is particularly important in patients with

depressed left ventricular function who may demonstrate

evidence suggesting a reversible tachycardia induced cardiomyopathy.

ablation may vary and the overall results of catheter ablation

differ depending on whether a patient does or does not have

paroxysmal AF. Pre-procedure arrhythmia monitoring is

also useful to determine if a patient has evidence of regular

supraventricular tachycardia that degenerates to AF as a

triggering mechanism or has a pattern of repetitive “focal

hours) with frequent rapid salvos of nonsustained atrial

tachycardia. Either of these triggering patterns of AF initiation

identifies a patient in whom a more limited ablation,

targeted at only the triggering arrhythmia focus or PV(s).

age, small LA size, the absence of hypertension and the

presence of paroxysmal AF may also identify patients in

whom consideration for a more targeted or limited ablation

Calkins et al. Catheter and Surgical Ablation of AF 831

ECG monitoring also plays an important role in the

follow-up after an ablation procedure. Early recurrences of

AF are common during the first one to three months following

arrhythmia monitoring to assess the efficacy of catheter

ablation is typically delayed for at least three months following

catheter ablation unless it is required to evaluate

arrhythmia symptoms during the early post ablation period.

The two main reasons to perform arrhythmia monitoring

following catheter ablation are clinical care and research.

From a purely clinical perspective, arrhythmia monitoring is

useful to determine if a patient’s complaints of “palpitations”

result from recurrent AF. Several studies have demonstrated

that complaints of “palpitations” often result

from atrial or ventricular premature beats and are not an

monitoring also has been shown to be of value in the

asymptomatic patient. Multiple studies have demonstrated

that asymptomatic AF commonly occurs in patients

of these asymptomatic episodes of AF may impact

decisions regarding continued anticoagulation and also

may impact the characterization of the procedure as “successful.”

Arrhythmia monitoring is also an essential component

of clinical trials aimed at assessing the outcomes

of catheter ablation procedures. There is general agreement

that arrhythmia monitoring should be incorporated

in all clinical trials designed to assess the efficacy of AF

catheter ablation tools and techniques. The suggested

monitoring strategies and minimum standards to be used

as part of clinical trials are discussed in the section on

Clinical Trial Considerations. These strategies and standards

may be useful in tracking outcome of clinical care

when assessing an institution’s performance standards

related to success and complications of AF ablation procedures.

However it is recognized that clinical endpoints

for defining success may include such important secondary

endpoints as elimination of symptomatic AF and

control of AF with previously ineffective antiarrhythmic

drugs after the AF ablation procedure.

Arrhythmia monitoring may be in the form of intermittent

sampling using a standard ECG or a patient activated event

monitor with or without a memory loop. Various types of

continuous monitoring systems are also available that range

from 1 to 7 day Holter monitoring to monitors that have the

capability of “auto-detecting AF” and can provide extended

periods of continuous monitoring. Implanted pacemakers with

atrial leads also allow the burden of AF to be assessed by

tracking the number and duration of mode switch episodes.

It is well established that the more intensively a patient is

monitored and the longer the period of monitoring, the

greater the likelihood of detecting both symptomatic and

complex and longer the method of monitoring that is used,

the lower the patient compliance.

There is a consensus among the Task Force that all patients

who undergo catheter ablation of AF, regardless of whether

or not they are enrolled in a clinical trial, should be seen in

follow-up at a minimum of three months following the

ablation procedure, and then every six months for at least

two years (Table 2). ECGs should be obtained at all follow-

up visits and patients who complain of palpitations

should be evaluated with an event monitor. Frequent ECG

recording using a manually activated event recorder and

counseling patients to take their pulse to monitor for irregularity

may serve as initial screening tools for asymptomatic

AF episodes. A one to seven day Holter monitor is the most

effective way to identify frequent asymptomatic recurrences

mobile cardiac outpatient telemetry system may identify

that patients receive detailed follow-up instructions

and be provided with contact information that will facilitate

prompt evaluation of symptoms consistent with a late complication

of the ablation procedure. Although there is no

consensus among the Task Force on the role of routine

imaging studies to screen for PV stenosis following ablation,

there was general agreement that the threshold for

using imaging tools for symptom evaluation should be low.

Strong consideration should be made to perform such imaging

studies when centers are beginning AF ablation programs

to confirm quality assurance. Recommendations for

follow-up of patients enrolled in clinical trials are discussed

in the Clinical Trial Considerations of the document.

Recurrence of AF is common early following catheter ablation

and is observed regardless of the catheter technique

can be observed in about 35%, 40% and 45% of patients by

circumferential ablation, inclusive of right and LA linear

ablation, arrhythmia recurrence can be observed in about

45% of patients during the first 3 months of follow-up,

being AF and the remaining being regular atrial tachycardia

period, the frequency of recurrent AF during the first days

post-ablation is variable; however, it should be noted that

about 15% of patients may complain of more frequent

of the AF early after the ablation procedure appears to be

higher in patients with persistent AF (47%) than in patients

patients with structural heart disease (47%–74%) than in

At present, there are insufficient data to estimate the role of

individual catheter techniques and technologies on early

recurrence of AF.

832 Heart Rhythm, Vol 4, No 6, June 2007

Although early recurrence of AF carries an independent

prompt immediate re-ablation attempts as up to 60% of

patients experiencing this event within the first months

post-ablation will not have any further arrhythmias during

history of persistent AF of greater than 30 days’ duration as

the only independent predictor of recurrent AF after an

initial blanking period in patients who had experienced an

isolation, the absence of structural and electrical abnormalities

of the LA was shown to distinguish patients with acute

Administration of antiarrhythmic drugs in patients at discharge

from hospital has been proposed to limit further

but the true efficacy of this strategy is unknown. Similarly,

in patients experiencing early recurrence of AF while on

antiarrhythmic drugs, the benefit of a change in therapy to

limit subsequent relapses of AF has not been investigated.

The mechanisms of post-ablation early transient AF have

not been elucidated. Among possible causes are: (1) a transient

stimulatory effect of RF secondary to the inflammatory

(2) a transient imbalance of the autonomic nervous

and (3) a delayed effect of RF ablation, as previously observed

to growth or maturation of the ablation lesions in the

a decrease in frequency of early transient AF may

actually represent a form of reverse atrial remodeling due to

partial AF control or AF control secondary to added antiarrhythmic

drug therapy.

Atrial tachycardias of new onset make up at least 10% of all

arrhythmias observed in the early phase following ablation

LA, and although most have a short cycle length of between

200 and 270 ms, longer cycle lengths have also been noted.

onset may complain of worsening symptoms due to a faster

mean ventricular rate than during their pre-ablation AF.

This arrhythmia is usually refractory to antiarrhythmic

drugs. Symptoms may be attenuated with drugs that reduce

AV nodal conduction. Similar to early AF after ablation,

spontaneous remission of regular LA tachycardia occurs in

approximately one third of patients within six months of the

The mechanisms underlying post-ablation regular atrial

tachycardias of new onset appear to be dependent on the

catheter technique used. In patients with prior segmental PV

isolation, a focal atrial origin, either located within PVs

exhibiting conduction recurrence or outside of PV (most

commonly from the LA roof or anterior to the right PVs),

Based on the response to pacing and adenosine infusion, the

focal PV rhythm appears to be due to microreentry involving

at least part of the ostium of the PVs although automatic

patients with prior LA circumferential PV isolation, regular

atrial tachycardias have been shown to originate from

within the isolated PVs and activate the contiguous atrial

tissue through conduction gaps across isolating lesions or

due to larger macroreentrant circuits typically around ipsilateral

circumferential ablation plus left posterior and mitral isthmus

linear ablation, macroreentrant circuits have been documented

with critical isthmuses at various sites, the mitral

isthmus, the inter-atrial septum, the LA roof and the coronary

mapping of the tachycardia during a second procedure results

in effective ablation of atrial tachycardia in approximately

flutter should be considered in the differential diagnosis of

regular atrial tachycardias observed following AF ablation,

Suppressive antiarrhythmic drugs are commonly employed

mechanism of AF in this setting may be different from that

of the patient’s clinical arrhythmia and may resolve completely

upon resolution of the inflammatory process. Accordingly,

some operators choose to treat all patients with

suppressive antiarrhythmic agents for the first one to three

months following ablation. The drugs employed for this

purpose vary, but most commonly are the drugs that have

been used unsuccessfully prior to ablation and include the

1C agents, sotalol, dofetilide, or amiodarone. Amiodarone is

commonly selected because it is well tolerated, is unlikely

to cause toxicity with short-term use, and is also an effective

agent for achieving rate control should AF recur or an atrial

The primary goal of ablative therapy for the treatment of

AF is elimination of symptomatic AF. Additionally, in

many patients it is desirable to eliminate all arrhythmias and

to be able to eliminate antiarrhythmic drug therapy. It

should be recognized, however, that many patients with a

good clinical response early after ablation with continued

antiarrhythmic drug therapy may be reluctant to stop drug

therapy to evaluate the clinical efficacy of the ablation

procedure alone. In addition, it is well recognized that

catheter ablation may be partially effective and allow a

patient with AF previously refractory to antiarrhythmic

therapy to be drug responsive. Therefore, if AF recurs

following discontinuation of antiarrhythmic drug therapy, it

is common practice to reinitiate the antiarrhythmic drug.

Many of these patients will prefer to continue antiarrhythmic

drug therapy, rather than undergo a repeat ablation

Calkins et al. Catheter and Surgical Ablation of AF 833

procedure. For these patients, drug therapy following ablation

is an acceptable long-term management strategy.

The use of angiotensin converting enzyme (ACE) inhibitors

or angiotenson receptor blockers to promote atrial

remodeling is actively being investigated. Attention to control

of hypertension and addressing other AF risk factors

such as sleep apnea and obesity remain an integral part of

AF management after the ablation procedure.

Recurrences of AF or atrial tachycardia after an initial AF

ablation procedure lead to a reablation procedure in 20% to

development of an atrial tachycardia are common during the

first two to three months after AF ablation, and may resolve

spontaneously, there is a consensus that repeat ablation

procedures should be deferred for at least three months

following the initial procedure (Table 2). It is also recognized,

however, that some patients will develop highly

symptomatic atrial arrhythmias that cannot be controlled

with antiarrhythmic therapy or slowed with rate controlling

medications and are best managed with a reablation procedure

within the first three months post ablation.

In general, patients with larger LA size and longer AF

duration typically experience a higher incidence of AF recurrence.

fail an initial attempt at ablation and undergo a repeat

ablation procedure demonstrate recurrent conduction in previously

isolated PVs rather than new arrhythmogenic foci

triggers that initiate AF can typically be provoked with

of PVs does not consistently predict recurrent

effective partial PV isolation and successful elimination of

the AF trigger or another mechanism is not known. Another

study identified uncommon or limited/delayed PV reconnection

patients with recurrent AF nearly uniformly demonstrated

PV reconnection, highlighting the importance of PV

reconnection as the probable etiology for AF recurrence. In

patients with arrhythmias due to reconduction from the PVs,

reisolation of the PV is frequently sufficient to treat these

when a macroreentrant mechanism is present.

Less commonly, the underlying mechanism of AF recurrences

is a focal trigger or atrial tachycardia outside the

PVs. Non PV focal triggers can typically be identified by

Alternatively some investigators have suggested that if the

PVs are found to be isolated during the re-ablation procedure

and no atrial tachycardia is present or can be induced,

AF may be induced to identify and ablate sites with continuous

atrial fractionated electrograms or with short atrial

cycle lengths which may represent sites of maintenance

Mild changes in autonomic modulation of the sinus node

have been described following ostial PV isolation as well as

including a slightly higher resting sinus rate, a decrease in

heart rate variability, and decreases in deceleration capacity

and acceleration capacity, often resolve within a month

following ostial PV isolation, but may be present at one year

following circumferential PV isolation.

The alterations in autonomic control probable result from

injury to the autonomic GP or injury to axons extending

from the GP. Radiofrequency applications during circumferential

PV ablation are frequently delivered close to the

superior left GP, and, the anterior right GP and occasionally

applications during PV ostial isolation probably

injure axons extending from the GP to the PV muscular

sleeve. Communication between GP is probably affected by

both approaches, which may alter autonomic input to the

sinus node. The observation that changes in sinus node

activity were similar in patients following circumferential

PV ablation (without GP ablation) to patients following GP

ablation (without circumferential PV ablation) supports this

The mild changes in autonomic regulation generally

have not been associated with inappropriate sinus tachycardia

or other symptoms. Therefore, evaluation in the postablation

period can be limited to patients presenting with

symptoms or persistent sinus tachycardia.

The incidence of very late recurrence (more than 12

months) after catheter ablation occurs in approximately 5%

higher if the follow-up period is extended beyond two years.

The incidence also may be related to the extent of ECG

monitoring and earlier recurrence may be missed in selected

patients with no or minimal symptoms. In one report, patients

identified as clearly being associated with very late AF

recurrence. If the recurrence occurs in the very late follow-

up (after one year), much of the AF appears most

commonly to still be triggered by foci from reconnected

non-PV ectopy from the right atrium, may play a

The efficacy of any type of ablation procedure can be

determined from a variety of sources including: (1) single

center randomized or nonrandomized clinical trials, (2)

multicenter randomized or nonrandomized clinical trials,

and (3) physician surveys. Among these sources of outcome

834 Heart Rhythm, Vol 4, No 6, June 2007

data, it is well recognized that data derived from large

prospective randomized clinical trials most accurately reflect

the outcomes that can be anticipated when a procedure

is performed in clinical practice. Unfortunately, as of the

time this document was prepared, there have been no large

randomized multicenter clinical trials performed to determine

the safety and efficacy of catheter ablation of AF.

The information that we will review in this document is

derived from three sources. First, we reviewed the results of

published single center studies which include a minimum of

we have summarized the results of five randomized clinical

When considering the published literature on catheter

ablation of AF, it is important to recognize that until the

writing of this Consensus Report, there has been no standardization

in the design of clinical trials of AF ablation.

There are many important aspects of an AF ablation trial

that can impact the results. Among the most important is the

patient population. It is now well recognized that the outcomes

of AF ablation differ considerably depending on

whether patients have paroxysmal, persistent, or longstanding

persistent AF. Similarly, variables such as age, concomitant

cardiac disease, and LA size are important determinants

of outcome. Other important considerations are the

duration of the blanking period, the frequency and intensity

of arrhythmia monitoring, whether patients with atrial flutter

during follow-up are classified as successes or failures,

the use of antiarrhythmic drugs, and the frequency and

timing of performance of repeat ablation procedures. Each

of these factors plays a role in how a particular study

defined “success.” Whereas some studies have defined success

as freedom from symptomatic AF during follow-up,

other studies have defined success as freedom from symptomatic

and asymptomatic episodes of AF. A third definition

of success employed by other studies is a greater than

90% reduction of AF burden, and a fourth definition of

success is the proportion of patients free of AF each month

of monitoring during follow-up. Each of these definitions

can be further modified based on whether patients who

remain on antiarrhythmic drugs at follow-up are classified

as having had a successful ablation procedure, a partially

successful ablation procedure, or a failed ablation procedure.

It is also important to recognize that the frequency of

detection of asymptomatic AF is directly dependent on the

duration and intensity of arrhythmia monitoring during follow-

up.

We reviewed the results of trials of catheter ablation of

were identified using a literature search based on the enrollment

of at least 50 subjects. Each of these trials either

compared the results of two ablation strategies, or reported

the results of a single ablation strategy. Almost all of these

studies enrolled patients with a mean age of less than 60

years, the great majority of whom were men. The reported

single procedure efficacy of catheter ablation in these trials

varied widely. The single procedure success of catheter

ablation of patients with paroxysmal AF ranged from 38%

to 78%. For patients with paroxysmal AF, most series reported

a single procedure efficacy of 60% or greater. In

contrast, the single procedure success of catheter ablation of

patients with persistent AF ranged from 22% to 45%, with

most centers reporting an efficacy of 30% or less. The single

procedure success of catheter ablation of patients with

mixed types of AF ranged from 16% to 84%. Not surprisingly,

repeat ablation procedures resulted in higher efficacy.

The reported multiple procedure success of catheter ablation

of patients with paroxysmal AF ranged from 54% to 80%,

with most series reporting a multiple procedure efficacy of

70% or greater. The multiple procedure success of catheter

ablation of patients with persistent AF ranged from 37% to

88%, with most centers reporting a multiple procedure efficacy

of 50% or greater. The multiple procedure success of

catheter ablation of patients with mixed types of AF ranged

from 30% to 81%. The results of these studies provide an

appreciation for the marked variability in the reported efficacy

of catheter ablation of AF.

There have been five randomized clinical trials performed

of catheter ablation of AF. The first study was published in

which randomized 70 patients (18–75 years) with paroxysmal

AF to treatment with antiarrhythmic therapy or catheter

ablation. Each patient in the antiarrhythmic drug arm was

treated with flecainide or sotalol. The primary endpoint was

recurrence of symptomatic or asymptomatic AF. No patients

received amiodarone. Three patients were lost to follow-

up. At one year of follow-up, 22 (63%) of 35 patients

randomized to antiarrhythmic drug therapy had at least one

AF recurrence as compared with 4 (13%) of 32 patients

treated with catheter ablation. The second study was published

trial that randomized 146 patients (18–70 years) with persistent

AF to treatment with catheter ablation versus cardioversion

alone. The primary endpoint was freedom from AF

or atrial flutter in the absence of antiarrhythmic drug therapy

one year after catheter ablation. An intention to treat analysis

revealed that 74% of patients in the ablation group and

58% of those in the control group were free of recurrent AF

without antiarrhythmic drug therapy at one year of followup.

The third randomized study of AF ablation was published

trial that investigated the adjunctive role of catheter

ablation in patients with paroxysmal or persistent AF. The

study population was comprised of 137 patients. At 12

months of follow-up, 9% of patients in the antiarrhythmic

drug arm were free of recurrent AF, as compared with 56%

of patients treated with catheter ablation and antiarrhythmic

Calkins et al. Catheter and Surgical Ablation of AF 835

drug therapy. The fourth randomized study of AF ablation

single center clinical trial, which compared the outcomes

of catheter ablation with antiarrhythmic drug therapy

in 199 patients with paroxysmal AF. Patients treated with

catheter ablation demonstrated a higher success rate (defined

as freedom from recurrent symptomatic or asymptomatic

AF). Eighty-six percent of patients treated with catheter

ablation were free of recurrent AF as compared with 22% of

patients treated with antiarrhythmic drug therapy. The fifth

and most recent randomized clinical trial found that 40 of 53

ablation patients (75%) were free of recurrent AF, as compared

with 7% AF freedom (4 of 59) with drug therapy. In

this trial, 63% of drug treated patients crossed over to

A worldwide survey on the methods, efficacy, and safety of

survey was based on a detailed questionnaire that was completed

by more than 180 centers located throughout the

world. At the time the study was completed in 2002, the

median number of AF ablation procedures that had been

performed at these centers was 38. At that time, each center

was performing catheter ablation for treatment of paroxysmal

AF, 53% of centers were performing ablation for treatment

of persistent AF, and 20% of centers were performing

catheter ablation for treatment of permanent AF. The outcomes

of nearly 9,000 AF ablation procedures were reported

by these centers. More than one ablation procedure

was performed in 27% of patients. The success rate, defined

as freedom from symptomatic AF in the absence of antiarrhythmic

therapy, was 52%. An additional 24% of patients

were free of symptomatic AF in the presence of a previously

ineffective antiarrhythmic drug. The mean duration of follow-

of major complications was 6%.

The results of the studies and surveys reviewed above provide

substantial evidence of the efficacy of catheter ablation

for treatment of patients with AF. However, it is also clear

that outcomes vary considerably. As noted previously, potential

factors that may impact outcome include: (1) differences

in technique, (2) differences in follow-up and definitions

of success, (3) differences in the use of antiarrhythmic

therapy, (4) differences in experience and technical proficiency,

and so forth. This consensus document should be

utilized by future investigators designing clinical trials to

further define the efficacy and safety of catheter ablation of

AF in a variety of patient populations.

A number of studies have incorporated some measure of

quality of life into their study design. Among these studies

which have examined the impact of catheter ablation on

of these nonrandomized trials has demonstrated a consistent

improvement in quality of life. It is important to interpret

these findings with caution because of the well-known placebo

effect.

Of much greater importance, however, are the results of

two randomized clinical trials that have also examined quality

of life. An initial study randomized 70 patients with

paroxysmal AF to treatment with antiarrhythmic therapy or

ablation demonstrated greater improvements in quality

of life at six months, as assessed using the Short-Form 36

health survey, as compared to those treated with antiarrhythmic

therapy. A subsequent study randomized 146 patients

with persistent AF to treatment with catheter ablation versus

that catheter ablation was more effective in maintaining

sinus rhythm. Patients who were in sinus rhythm

demonstrated a greater improvement in the symptom severity

score than those patients with recurrent AF or flutter.

Although these findings demonstrate an improvement in

quality of life based on a randomized clinical trial, these

studies were unblinded and therefore the possibility of a

placebo effect can still not be eliminated.

During the past decade, extensive animal based and clinical

research has demonstrated that AF results in electrical and

these studies, taken as a whole, suggest that AF can be

viewed in part as a rate related atrial cardiomyopathy. To

the extent that other types of rate related cardiomyopathies

lead to reversible chamber dilatation and dysfunction, it was

anticipated that reverse remodeling might also occur in a

subset of patients who underwent catheter ablation for treatment

of AF.

Consistent with this hypothesis, several studies have

been performed that have examined LA size prior to and

demonstrated a 10% to 20% decrease in the dimensions of

the LA following catheter ablation of AF; regardless of

whether echocardiography, MR imaging, or CT was used

for LA imaging. Although the precise mechanism of this

decrease in size is not known, it appears consistent with

reverse remodeling. Alternatively scar formation by the

ablation procedure may cause the observed reduction in

atrial size. Because of this data, some electrophysiologists

counsel their patients that AF ablation is indicated, even in

the asymptomatic patient, because it will prevent progressive

atrial enlargement. The Task Force does not believe

that the potential reversal of atrial remodeling should by

itself be considered as an appropriate indication for AF

ablation.

The impact of catheter ablation of AF on LA transport

function has been investigated in two studies with conflicting

836 Heart Rhythm, Vol 4, No 6, June 2007

function remains an active area of investigation. However,

to the extent that AF effectively results in no booster pump

function of the LA, there is general agreement that restoration

of sinus rhythm can improve atrial function. The issue

of whether catheter ablation of AF in patients with paroxysmal

AF who are predominantly in sinus rhythm improves

or impairs LA transport function requires further study.

The impact of catheter ablation of AF on left ventricular

One study compared the outcomes of AF ablation in 58

patients with heart failure and an ejection fraction (EF)

patients with heart failure, AF ablation resulted in improvements

in LV function, left ventricular dimensions, exercise

capacity, symptoms and quality of life. In this study, more

than 70% of heart failure patients demonstrated a marked

improvement in EF (an increase of 20% or more, or to a

study that compared the outcomes of 94 patients with impaired

ventricular function (EF 40%) with 283 patients

was successful in 73% of patients with impaired ventricular

function as compared with 87% of those with normal ventricular

function. A non-significant improvement in EF of

4.6% was observed, combined with an improvement in

quality of life. Improvements in left ventricular function

These studies, taken as a group, provide strong evidence

that catheter ablation of AF, particularly among those patients

with impaired ventricular function, results in improvement

in ventricular function. Larger studies are

needed to determine exactly what component of this improvement

in ventricular function results from improvement

in rate control, as compared to restoration of sinus rhythm

per se.

Catheter ablation of AF is one of the most complex interventional

electrophysiologic procedures. It is therefore to be

expected that the risk associated with AF ablation is higher

than for ablation of most other cardiac arrhythmias. This

section reviews the complications associated with AF ablation

procedures. Particular attention is focused on the most

frequently occurring complications and those likely to result

in prolonged hospitalization, long-term disability, or death.

We recognize that rarer complications with significant sequelae

can occur. It must be remembered that the publications

from which these data are derived originate from large

volume centers where complications would be expected less

frequently than in lower volume centers. The world-wide

survey of AF ablation reported that at least one major

complication was seen in 6% of patients but with only four

might be regarded as providing more representative complication

rates, it must be recognized that this was a voluntary

survey and likely underestimated the true complication

rate. The Task Force strongly recommends that standardized

reporting of complications be included in all published

reports on the outcome of AF ablation. A major complication

is defined as a complication that results in permanent

injury or death, requires intervention for treatment, or prolongs

or require hospitalization (Table 2).

Cardiac tamponade is the most common potentially life

threatening complication associated with AF ablation. It is a

well recognized but infrequent complication of routine cardiac

electrophysiology procedures. The markedly higher

incidence of cardiac tamponade occurring in up to 6% of AF

of important differences, including extensive intra-cardiac

catheter manipulation and ablation, the common need

for two or more transseptal punctures, and the need for

systemic anticoagulation.

Cardiac perforation leading to tamponade can result from

overheating during energy delivery with development of a

“pop” or from direct mechanical trauma, especially through

the LA appendage, a misdirected trans-septal puncture (including

a puncture performed too posteriorly that exits the

right atrium into the pericardium before entering the LA),

with the needle exiting the LA via the roof, LA appendage,

or the lateral LA wall. Among the series of AF ablation

reviewed for this document, cardiac tamponade was reported

as a complication in two thirds, with an incidence of

up to 6%. One study recently reported cardiac tamponade in

for tamponade in this study were linear ablation lesions and

higher ablation power. A “pop” was heard during eight of

these 10 cases. Another large series reported cardiac tamponade

Two of these patients required surgical intervention. In

contrast to the prior study, no “pop” was reported. The

Worldwide Survey of AF Ablation reported a 1.2% incidence

Cardiac tamponade presents either as an abrupt dramatic

fall in blood pressure, or more insidiously, as a gradual

decrease in blood pressure. In the latter case, administration

of fluid may return the blood pressure to normal before it

subsequently declines. However, it is vital that operators

and staff be vigilant to the development of cardiac tamponade

as a delay in diagnosis may be fatal. All members of this

Task Force continuously monitor the systemic arterial pressure

during and following AF ablation procedures. The

development of hypotension in any patient should be assumed

to indicate tamponade until proven otherwise by

immediate echocardiography. An early sign of cardiac tamponade

is a reduction in the excursion of the cardiac silhouette

on fluoroscopy with a simultaneous fall in systemic

Calkins et al. Catheter and Surgical Ablation of AF 837

blood pressure. ICE has been reported to allow earlier detection

The majority of episodes of cardiac tamponade can be

managed successfully by immediate percutaneous drainage

and reversal of anticoagulation with protamine. This is best

achieved by sub-xiphoid Seldinger puncture of the pericardial

sack and placement of an intra-pericardial catheter.

After initial aspiration, the blood pressure promptly returns

to normal. Once the pericardial space has been drained, the

patient needs to be monitored for ongoing bleeding with the

drainage catheter in place. Rarely, if there has been a tear,

percutaneous drainage may be inadequate and surgical

AF ablation procedures should only be performed in hospitals

equipped or prepared to manage these types of emergencies

with access to emergency surgical support when

required. Three cases have been reported of emergent drainage

of a pericardial effusion through a sheath either inadvertently

or purposely placed into the pericardial space

not be a recommended approach.

PV stenosis is a well-recognized complication of AF ablation

that results from thermal injury to PV musculature.

Since first reported in 1998, numerous studies have sought

to determine the incidence, cause, diagnostic strategy, and

Although the precise pathophysiological mechanisms are

still uncertain, a progressive vascular reaction leading to

replacement of necrotic myocardium by collagen has been

reported after extensive radiofrequency energy application

variation results from differences in the ablation technique,

definition of PV stenosis, intensity of screening for this

complication and the date at which the study was performed.

When PV ablation for treating AF began in the late

1990s, investigators were unaware that PV stenosis was a

potential complication. In contrast, today, operators understand

that PV stenosis can be prevented by avoiding RF

energy delivery within a PV. This increased awareness and

improvements in imaging modalities (such as ICE and computerized

imaging systems with digital image fusion) have

enabled better identification of the true PV ostium and

resulted in a dramatic reduction in the incidence of PV

stenosis. It is notable that less than one third of the members

of this consensus Task Force routinely screen for asymptomatic

PV stenosis during follow-up. Most only investigate

for PV stenosis in patients with suggestive symptoms, acknowledging

that even severe PV stenosis can be asymptomatic.

It is unknown whether early diagnosis and treatment

of asymptomatic PV stenosis provides any long-term

advantage to the patient. It is recommended that centers

beginning to perform AF ablation procedures, or those transitioning

to a new AF ablation technique or approach, routinely

obtain follow-up CT or MR scans to screen for PV

stenosis during their initial experience for quality control

purposes.

CT or MR imaging of the PVs prior to, and several

months following, catheter ablation are the most precise

that both of these imaging modalities are equally accurate in

determining PV size and detecting PV stenosis. According

to the percentage reduction of the luminal diameter, the

severity of PV stenosis is generally defined as mild (50%),

more likely with severe stenoses, but even severe PV stenosis

or complete PV occlusion may be asymptomatic. Late

progression of PV stenosis is reported, but the precise incidence

Among the series of AF ablation reviewed for this document,

PV stenosis was reported in 10%. Although these

may reflect the infrequency of PV stenosis, few performed

routine follow-up CT or MR imaging to screen for asymptomatic

PV stenosis. Saad et al recently reported severe PV

stenoses following 21 of 608 AF ablation procedures (3.4%)

where the development of symptoms correlated with severe

Survey of AF Ablation reported a 0.32% of acute PV stenosis

and a 1.3% incidence of persistent PV stenosis. Percutaneous

or surgical intervention for treatment of PV stenosis

Symptoms of PV stenosis include chest pain, dyspnea,

cough, hemoptysis, recurrent lung infections and those of

should be warned of these possible symptoms to

avoid inappropriate subsequent presentation to respiratory

or other specialist physicians. Whether symptoms develop

may depend upon the number, length, and severity of the

stenoses and the time over which they develop. Cases have

been reported of even total PV occlusion being asymptomatic

because of compensatory dilatation of the ipsilateral

PV. A ventilation perfusion scan may be useful to screen for

obtained.

The preferred therapy for severe symptomatic PV stenosis

benefit from elective PV stenting is uncertain but this may

be required if balloon angioplasty alone is inadequate

acutely or is followed by restenosis. However, restenosis

can develop despite stent placement. The role of surgery is

not defined but may be considered for clinically important

PV occlusion where angioplasty and stenting has failed.

The development of an atrial-esophageal fistula is one of

the most serious complications of AF ablation. Although

its precise incidence is unknown, it has been estimated to

occur after less than 0.25% of AF ablation procedures.

178,189,192,194,257,261-263

The esophagus is close to the posterior wall of the

energy heats this region of the LA can result in direct

838 Heart Rhythm, Vol 4, No 6, June 2007

damage of the esophageal wall, or affect esophageal innervation

and its blood supply. The development of atrioesophageal

fistula has been reported most commonly following

ablation electrode.

Early diagnosis of an atrial esophageal fistula is difficult

as it typically presents two to four weeks after the ablation

procedure. The commonest symptoms are fever, chills, and

recurrent neurological events. Presentations that are more

dramatic are septic shock or death. If suspected, the best

diagnostic modalities are CT or MR imaging of the esophagus.

Although a barium swallow may detect a fistula, its

sensitivity is low. Endoscopy is a diagnostic modality that

should be avoided as insufflation of the esophagus with air

has resulted in a devastating massive cerebrovascular accident

and death resulting from a large air embolus.

It must be recognized that most patients who have developed

an atrial esophageal fistula have died, and the survivors

are often left with disability from cerebrovascular

events. Nevertheless, early diagnosis is important because

there have been a number of patients with esophageal perforation

who have achieved full recovery by urgent surgical

intervention. There has been one case report of a favorable

Because of the severe consequences of an atrial esophageal

fistula, it is vital to avoid this complication. Currently,

a number of different approaches are being employed with

this aim. Please refer the section on Other Technical Aspects

for a more detailed discussion of these techniques. The

most common practice decreases power delivery, limiting

energy to 25 to 35 watts, decreases tissue contact pressure,

and moves the ablation catheter every 10 to 20 seconds

when close to the esophagus. However, owing to the rarity

of this complication, it remains unproven whether these

practices lower or eliminate the risk of esophageal injury.

Phrenic nerve injury is an important but rare complication

injury, usually to the right phrenic nerve, which is

located near the right superior PV and the superior vena

can result in left phrenic nerve damage. The development

of phrenic nerve injury has resulted from AF

ablation using RF, cryoablation, ultrasound, and laser ablation.

Despite the rarity of this complication, it is important for

those performing AF ablation to be aware of it and know

how to avoid it. Right phrenic nerve injury has been seen

more frequently with the use of balloon ablation catheters in

the right superior PV, irrespective of the energy

Phrenic nerve damage can be asymptomatic or can cause

dyspnea, hiccups, atelectasis, pleural effusion, cough and

can be confirmed by fluoroscopy showing unilateral diaphragmatic

paralysis. Strategies to prevent phrenic nerve

damage include high output pacing to establish whether the

phrenic nerve can be captured from the proposed ablation

site before ablation; phrenic nerve mapping by pacing along

the superior vena cava (SVC) to identify the location of the

phrenic nerve; ensuring proximal/antral ablation when ablating

around the right upper PV; and fluoroscopic monitoring

of diaphragmatic excursion during ablation, with/

without phrenic nerve pacing from the SVC and above the

ablation site during energy delivery. Energy delivery should

be interrupted immediately when diaphragmatic movement

between 1 day and more than 12 months. However,

there have been some cases of permanent phrenic nerve

injury. There is no active treatment known to aid phrenic

nerve healing.

Embolism of air or thrombus is one of the most significant

complications of ablation of AF and both are potential

causes of cerebral, coronary, or peripheral vascular compromise.

The incidence of thrombo-embolism associated with

AF ablation is reported to be between 0% and

clinical trials reviewed for preparation of this document

reported one or more cerebrovascular events. Thromboembolic

events typically occur within 24 hours of the ablation

procedure with the high risk period extending for the first

thromboembolism has been reported in one study following

A number of potential explanations for the development

of thromboembolic complications have been proposed.

These include the development of thrombi on stationary

char formation at the tip of the ablation catheter and at the

site of ablation, and disruption of a thrombus located in the

atrium prior to the ablation procedure. Diagnosis of a symptomatic

thrombo-embolic event is usually straightforward

when ischemia or infarction results from arterial occlusion

interrupting perfusion of dependent tissue. The manifestation

depends upon where the occlusion occurs: intracranial,

coronary arterial, abdominal, or other peripheral

arterial beds. We have previously discussed the prevention

of thromboembolism by intraprocedural and post

procedural anticoagulation in the section on Other Technical

Aspects. Treatment of a thrombo-embolic event will

vary according to the location of the embolus. Peripheral

arterial embolization may be amenable to surgical thrombectomy,

whereas, cerebral embolization has traditionally

been managed conservatively and the consequences

accepted. However, there is growing interest in aggressive

early management of such events, with either thrombolytic

drugs or percutaneous interventional techniques.

Calkins et al. Catheter and Surgical Ablation of AF 839

The most common cause of air embolism is introduction of

air into the trans-septal sheath. While this may be introduced

through the infusion line, it can also occur with

suction when catheters are removed. Air embolism has been

reported with coronary angiography and ablation procedures.

161,163,273,274

Air embolism to the cerebral vasculature can be associated

with altered mental status, seizures, and focal neurologic

signs. The central nervous system dysfunction is attributable

to both mechanical obstruction of the arterioles

and thrombotic-inflammatory responses of air injured epithelium.

is based on clinical suspicion, prompt MRI or CT scans

obtained before the intravascular air is rapidly absorbed

may show multiple serpiginous hypodensities representing

air in the cerebral vasculature, with or without acute infarction.

AF ablation is acute inferior ischemia and/or heart block.

This reflects preferential downstream migration of air emboli

into the right coronary artery. Supportive care usually

results in complete resolution of symptoms and signs of

inferior ischemia within minutes.

It is imperative that all infusion lines be monitored

closely for bubbles. Whenever catheters are removed, they

should be withdrawn slowly to minimize suction effects and

the fluid column within the sheath should be aspirated

simultaneously. The sheath should then be aspirated and

irrigated to ascertain that neither air nor blood has collected

within the sheath, because both are potential sources of

embolism. Treatment should be initiated immediately in the

laboratory if cerebral air embolism is suspected. The most

important initial step is to maximize cerebral perfusion by

the administration of fluids and supplemental oxygen,

which increases the rate of nitrogen absorption from air

bubbles. It may be beneficial to briefly suspend the patient

oxygen may reverse the condition and minimize endothelial

thrombo-inflammatory injury if it is started within a few

Regular atrial tachycardias of new onset may be observed

for the first time in 5% to 25% of patients who have

to recognize that many of these arrhythmias are

self-limited and will resolve spontaneously during the first

three to six months of follow-up. For this reason, initial

efforts should be focused at suppressing these arrhythmias

with antiarrhythmic medications or controlling the ventricular

response with AV nodal blocking drugs. More detailed

information on the etiology and approach to management of

these arrhythmias is discussed in the section on Follow-up

Considerations.

Vascular complications are common and include groin hematoma,

retroperitoneal bleed, development of a femoral

arterial pseudoaneurysm, or a femoral arteriovenous fistula.

The published incidence of vascular complications varies

from 0% to 13%. One recent literature review on AF ablation

described a 13% incidence of hematoma and a 1%

A worldwide survey of 8,745 AF ablation procedures found

an incidence of femoral pseudoaneurysm and arteriovenous

a 4% rate of vascular complications, with 2 cases of pseudoaneurysm

and 1 case of arteriovenous fistula, were observed

The high incidence of these complications likely reflects

the number and size of venous catheters used and the use of

an arterial line associated with intense anticoagulation prior

to and following the ablation procedures. In most EP laboratories,

patients are fully anticoagulated during and following

the ablation procedure with interruption of anticoagulation

for less than four to six hours to allow for sheath

removal.

Although vascular complications rarely cause long-term

disability or death, they are important because they prolong

hospitalization, cause inconvenience and discomfort to the

patient and may require a transfusion. The risk of vascular

complications can be minimized by technical proficiency

with vascular access, avoidance of very large sheaths, and

care with anticoagulation. Large hematomas usually can be

managed conservatively. Echo-guided manual compression

and percutaneous or surgical closure are all effective treatments

of femoral A-V fistulae or pseudoaneurysms after

An uncommon complication of RF ablation of AF is acute

circumflex coronary artery occlusion following RF energy

delivery to create a “mitral isthmus” linear lesion. This

occurred once in 356 patients in whom RF energy was

delivered inside the coronary sinus to complete the line of

which changes according to the distribution of the circumflex

artery and its dominance. Depending on the level of

sedation, the patient may complain of chest pain. A more

posterior mitral isthmus line may avoid this complication

but may increase the risk of injury to the esophagus. Haissaguerre’s

group has suggested the reduction of energy

power if RF applications are needed inside the coronary

required, standard percutaneous therapy for acute coronary

occlusion should be initiated.

A recent study described a series of patients with a new

extracardiac complication of AF ablation which was termed

was characterized by abdominal bloating and discomfort

developing within a few hours to two days after the

840 Heart Rhythm, Vol 4, No 6, June 2007

ablation procedure. The incidence was 1% in a series of 367

patients. The authors supposed that RF energy delivered in

the posterior wall of the LA damaged the periesophageal

vagal plexi so that it might be avoided by the same maneuvers

suggested to avoid atrio-esophageal fistulae (see

above). Upper gastrointestinal investigation showed pyloric

spasm, gastric hypomobility and a markedly prolonged gastric

half-emptying time. Two of four patients recovered

fully within two weeks. Because pyloric spasm was the

prominent component of this syndrome, pyloric dilatation

was performed, mechanically in one patient, and by local

injection of botulinum toxin in the other, with transient

improvement.

Catheter ablation of AF is often a complex and long

procedure requiring long fluoroscopy exposure time and

often preceded and followed by CT scans. An important,

less easily recognized, and rarely considered potential

complication of AF ablation is the delayed effect of the

radiation received by the patients, including acute and

the various components of the procedure such as double

trans-septal catheterization, PV angiography, and extensive

RF applications. One recent study reported mean

fluoroscopy durations for AF procedures of greater than

60 minutes in both left anterior oblique (LAO) and right

anterior oblique (RAO) projections. The mean peak skin

LAO projection. This translates into a lifetime risk of

excess fatal malignancies (normalized to 60 minutes of

fluoroscopy) of 0.07% for female and 0.1% for male

patients. The relatively low radiation exposure to the

patients in this study, despite the prolonged fluoroscopy

durations, was attributable to the state-of-the-art very low

frame rate pulsed fluoroscopy, the avoidance of magnification,

and the optimal adjustments of fluoroscopy exposure-

rates. The resulting lifetime risk of malignancy

was thus within the range previously reported for ablation

of junctional reentry tachycardias. However, this study

demonstrated that catheter ablation of AF required significantly

greater fluoroscopy duration and radiation exposure

than simpler catheter ablation procedures. Thus,

and especially because AF ablation procedures often

need to be repeated, electrophysiologists should make

every attempt to minimize radiation exposure.

Increasing availability and familiarity of electrophysiologists

reduce fluoroscopy time and the need for biplane fluoroscopy.

The use of remote navigation systems is also likely to

significantly reduce radiation exposure to the patients and

especially to the electrophysiologists who perform these

procedures.

Entrapment of the mitral valve apparatus by a curvi-linear

electrode mapping catheter is an uncommon complication

of the circular electrode catheter into the ventricle with

counterclockwise rotation of the catheter resulting in entrapment

of the circular catheter in the mitral vale apparatus.

When suspected, it is important to confirm the diagnosis

with echocardiography. Although successful freeing of the

catheter has been reported with gentle catheter manipulation

and advancing the sheath into the ventricle, great caution

must be used as it is possible to tear the mitral valve

apparatus. It is recommended that if gentle attempts to free

the catheter fail, elective surgical removal of the catheter

should be performed.

The strategies, specific methods, and technology pertaining

to ablation of AF are evolving. Accordingly, the guidelines

for training to perform this procedure must be flexible in

recognition of different approaches and technologies that

will change with advances in the field. Training for ablation

of AF should encompass six fundamental principles:

1. Appropriate selection of patients

2. Knowledge of anatomy of the atria and adjacent structures

3. Conceptual knowledge of strategies to ablate AF

4. Technical competence

5. Recognition, prevention, and management of complications

6. Appropriate follow-up and long-term management

The training required in each of these areas differs from

other ablation procedures because in comparison, ablation

of AF is technically more difficult, is associated with greater

risks, and requires more careful follow-up.

The only absolute contraindication for catheter ablation of

AF is the presence of a LA thrombus. There are no other

areas of consensus about absolute contra-indications to ablation

of AF, but trainees should recognize clinical attributes

that may increase the difficulty of a transseptal puncture,

increase the risk of the procedure, and affect long-term

outcomes. These factors are discussed in a prior section of

this document. The trainee should also develop the judgment

to decide whether conscious sedation or general anesthesia

would be most appropriate for the case under consideration.

It is also important to assess the severity of symptoms

related to AF and the potential benefit of an ablation procedure.

Trainees should be experienced in counseling patients

about the potential risks and benefits of an ablation

procedure and should be able to apply this knowledge for

recommendations specific to the needs of individual patients.

They should also take into consideration the prior use

Calkins et al. Catheter and Surgical Ablation of AF 841

of antiarrhythmic drugs and pharmacologic alternatives to

ablation of AF.

It is also important for electrophysiologists involved with

catheter ablation to be knowledgeable about surgical ablation

techniques for AF. In particular, electrophysiologists

who perform AF ablation procedures must be aware of the

indications, techniques, and outcomes of surgical approaches

for ablation of AF. This applies both to the new

minimally invasive surgical approaches, AF surgery combined

with other cardiac surgical procedures, and the Cox

Maze-III procedure (see section on Surgical Ablation of

Atrial Fibrillation).

Detailed knowledge about the anatomy of the LA and its

adjacent structures is crucial for performing the technical

aspects of trans-septal puncture and cannulation, LA mapping,

and isolation of the PVs or modification of the substrate

that sustains AF. The trainee must recognize the

anatomic relationship of the atria, superior vena cava, and

PVs to the pulmonary arteries, aorta, mitral annulus, phrenic

nerves, sympathetic and parasympathetic innervation,

esophagus, and other mediastinal structures. These anatomic

relationships affect the ability to perform the procedure

successfully and to avoid complications.

Trainees should understand the pathophysiology of AF and

its implications for strategies to ablate AF. This includes the

role of the PVs, the superior vena cava, the musculature of

the LA, and the potential impact of autonomic stimulation.

They should understand the rationale for isolation of the

PVs and elimination of foci that trigger AF and the basis for

broad circumferential ablation of tissue or elimination of

fractionated potentials that appear to alter the substrate that

sustains AF.

The technical skills needed for ablation of AF are substantial.

These include trans-septal needle puncture and cannulation

of the LA, precise manipulation of the catheter for

mapping and ablation, identification of the pulmonary ostia,

adjustment of the energy used for ablation, and the appropriate

use of fluoroscopy, radiographic contrast for imaging,

3D mapping systems or intra-cardiac echocardiography.

There are substantial differences among laboratories in the

use of radiographic contrast imaging, electroanatomic mapping

or intra-cardiac echocardiography, the number and

types of catheters used to identify electrical endpoints and to

perform ablation. The degree of expertise gained in the use

of a specific technology will depend on where training is

completed. Nonetheless, trainees should be expected to understand

the potential advantages and limitations of these

systems and should have the ability to interpret basic images

and electrical recordings obtained from these different

methodologies. They should be well versed in the principles

of radiation safety for patients and the medical personnel

who perform ablation procedures.

Training programs should emphasize the interpretation

of intra-cardiac electrograms for recognition of PV potentials

and determination of when electrical isolation of a PV

has been achieved, the role of coronary sinus pacing in the

differentiation of far field electrograms from PV potentials,

identification of fractionated low-amplitude LA potentials,

and techniques required to map and ablate right and/or LA

tachycardias or atrial flutter. Trainees need to be skilled in

identifying the presence, mechanism, origin, and ablation of

other supraventricular tachycardias that may act as triggering

mechanisms for AF such as AV nodal reentrant tachycardia

and AV reentrant tachycardia.

Most laboratories use radiofrequency energy to ablate

AF. Several alternative energy sources and/or balloon-based

delivery systems are under evaluation. Trainees should understand

the potential advantages and disadvantages of

these alternative energy sources and delivery systems. The

use of remote navigation technologies is also evolving. As

these or other technical advances become integrated into

common usage, their utility and limitations should be incorporated

into the body of knowledge that is required for

trainees.

The American College of Cardiology/American Heart

Association 2006 update of the clinical competence statement

on invasive electrophysiology studies, catheter ablation,

and cardioversion proposed a minimum of 30 –50

AF ablation procedures for those who undergo fellowships

underestimates the experience required for a high

degree of proficiency. Exact numerical values are difficult

to specify because technical skills develop at different

rates. Nonetheless, comparisons of high and low

volume centers suggest that outcomes are better at centers

Trainees who intend to perform ablation of AF independently

should consider additional training after the standard

fellowship is completed.

Electrophysiologists who have already completed fellowship

training and are proficient in performing ablation

procedures may wish to develop the skills required to perform

ablation of AF. The technical proficiencies required

for these procedures exceed those employed for most standard

ablation procedures. Moreover, the risks of ablation

procedures for AF are greater than other common procedures

performed in the electrophysiology laboratory. Accordingly,

electrophysiologists who have already completed

a fellowship and choose to undergo training for ablation of

AF should observe colleagues with a high degree of expertise

and a period of supervision is advisable. In the absence

of definitive data numerical requirements are arbitrary, but

as a guideline, it seems appropriate for experienced electrophysiologists

to be supervised when they begin to perform

these procedures. The exact number may depend on prior

experience with trans-septal punctures and cannulation of

842 Heart Rhythm, Vol 4, No 6, June 2007

the LA. Electrophysiologists should perform several ablation

procedures for AF per month if they intend to remain

active in this area. All electrophysiologists should track the

outcomes of their procedures and verify that appropriate

follow-up has been arranged. It would be inappropriate for

cardiologists who are not trained in electrophysiology to

consider performing ablation procedures for AF. The selection

of patients and interpretation of atrial flutter and other

atrial tachycardias that are often seen in patients with AF

require training that is unique to electrophysiology fellowships.

As previously discussed, ablation of AF is associated with

substantial risks that must be recognized. Training programs

must emphasize techniques that reduce these risks. This

includes careful manipulation of catheters, appropriate use

of anticoagulation, modification of energy delivered on the

posterior wall of the LA, and the risk of applying energy

within the PVs or LA appendage. Fellows should be trained

to suspect cardiac tamponade or internal bleeding as a

common cause of hypotension. Training should also include

management of these complications. It is preferable for

fellows to undergo training in pericardiocentesis. If trainees

do not gain proficiency in pericardiocentesis, they must

recognize the need for immediate access to a physician who

has mastered these skills. They should understand the risks

of conscious sedation, which include hypoventilation, aspiration,

and respiratory arrest. They should also recognize

the delayed time course associated with the development of

atrial-esophageal fistulas or PV stenosis, as well as the

appropriate steps need to diagnose and manage these problems.

Management of patients after hospital discharge can be

complex and requires commitment from the following physician.

Individuals undergoing training in AF ablation

should participate in a longitudinal clinic in which these

patients are followed. Experience must be gained in diagnosis

and management of post procedure complications

including esophageal injury, PV stenosis, and late hematoma,

pseudoaneurysm or AV fistula. Since the prevalence

of some of these complications is very low, it is possible

that the trainee will not have first hand experience with

patients. Therefore, supplementation of clinical experience

with didactic presentations on diagnosis and management of

post ablation complications is required. Prophylaxis against

and management of post procedure atrial arrhythmias, including

timing of repeat ablation and use of concomitant

antiarrhythmic drugs, must be taught to trainees. Finally, the

training experience must address the risk– benefit decision

making regarding the use of intermediate and long-term

anticoagulation therapy.

Following extensive experimental investigation, the Maze

procedure was introduced for the surgical treatment of AF

designed to interrupt all macro-reentrant circuits that might

potentially develop in the atria, thereby precluding the ability

of the atrium to flutter or fibrillate. Fortuitously, the

operation also isolated all of the PVs and posterior LA. In

contrast to previous unsuccessful procedures, the Cox-Maze

procedure successfully restored both atrioventricular synchrony

and a regular heartbeat, and decreased the incidence

this procedure and the fact that the LA appendage was

amputated. The operation involves creating multiple strategically-

placed incisions across both the right and left atria.

The surgical incisions were placed so that the sinus node

could “direct” the propagation of the sinus impulse throughout

both atria. It also allowed most of the atrial myocardium

to be activated, resulting in preservation of atrial transport

the Cox-Maze III, has become the gold standard for

the surgical treatment of AF. In late follow-up from experienced

centers, over 90% of patients have been free of

Despite its proven efficacy, the Cox-Maze procedure did not

gain widespread application. Few cardiac surgeons were

willing to add the operation to coronary revascularization or

valve procedures due to its complexity and technical difficulty.

In an attempt to simplify the operation and make it

more accessible to the average surgeon, groups around the

world replaced the incisions of the traditional cut-and-sew

Cox-Maze procedure with linear lines of ablation. These

ablation lines have been created using a variety of energy

sources including RF energy, microwave, cryoablation, laser

The various technologies can be organized into two major

groups: those that use a unipolar energy source and those

that use a bipolar clamp. The unipolar energy sources (cryosurgery,

unipolar RF energy, microwave, laser, HIFU) radiate

either energy or cold from a single source. None of the

unipolar devices provide the surgeon with an indication of

when the ablation results in a transmural lesion. Since most

of these ablation systems were released clinically without

dose-response studies, their use has led to occasional collateral

unipolar energy sources have had difficulty creating transmural

lesions when used from the epicardial surface on the

blood pool makes transmural lesions difficult to

achieve. With microwave energy, there is a direct relationship

between the depth of lesion penetration and the degree

focused delivery of energy. However, these energy sources

have a relatively fixed depth of penetration.

Calkins et al. Catheter and Surgical Ablation of AF 843

Bipolar RF ablation has been able to overcome some of

two closely approximated electrodes embedded in the

jaw of a clamp device, the energy is focused and results in

relatively discrete lesions. The energy is confined to within

the jaws of the clamp, reducing the possibility of collateral

cardiac or extra-cardiac damage. By measuring the tissue

conductance between the two electrodes, algorithms have

been developed which have accurately predicted lesion

weakness of these devices is that they can only ablate tissue

that can be clamped within the jaws of the device. This has

limited the potential lesion sets, particularly in the beating

heart. Moreover, in the clinical situation, multiple ablations

have often been required to achieve entrance and exit block.

These devices have been incapable of fully ablating the

right and LA isthmus, and have required adjunctive unipolar

ablation to perform a complete Cox-Maze III lesion set.

Nevertheless, the development of these new ablation

technologies has benefited the surgical treatment of AF by

making a technically difficult and time-consuming operation

easier for all cardiac surgeons to perform. At present,

the majority of patients undergoing open-heart surgery who

have persistent AF are offered concomitant AF surgery at

experienced centers. Replicating the full Cox-Maze lesion

set with linear lines of ablation has been shown to be both

feasible and clinically effective. A number of groups have

reported excellent results with ablation-assisted Cox-Maze

procedures, with over 90% of patients free from symptomatic

patients who underwent an ablation-assisted Cox-Maze with

those having had a traditional cut-and-sew Cox Maze III,

showed no differences in freedom from AF at 3, 6 and 12

Currently the limitations of the energy delivery devices

and the attempt to deploy them through minimal access

incisions or ports place constraints on the location and

number of ablation lesions that can be performed. The

impact of these alternative lesion patterns and the less invasive

surgical approaches on results requires further observational

prospective analysis.

The term “Maze” procedure is appropriately used only to

refer to the lesion set of the Cox-Maze III. Less extensive

lesion sets should not be referred to as a “Maze” procedure.

In general, surgical ablation procedures for AF can be

grouped into three different groups: (1) a full Cox-Maze

procedure, (2) LA lesion sets, and (3) PV isolation.

In patients undergoing cardiac surgery, the issue that prior

AF might place the patient at risk for early and late mortality

has not been fully resolved. Patients who have AF

before cardiac surgery have been shown to be at an increased

risk, and are generally older, have worse ventricular

have tried to assess whether AF is an independent risk factor

for death. Late survival was reduced as determined from

propensity matched studies and multivariable analysis in

In one additional study, AF was associated with a higher

identified for those undergoing aortic valve replacement

is not just a marker for high-risk patients, but is an independent

risk factor for increased mortality. The unproven

implication is that efforts to eliminate AF at surgery may

improve survival or reduce late adverse cardiac events.

While this has not been supported by prospective, randomized

studies, retrospective studies have shown improved late

survival in patients with longstanding AF and mitral valve

disease in patients who underwent a Cox-Maze procedure in

addition to their mitral valve surgery when compared to

study showed that major adverse cardiac events occurred

more commonly in patients with pre-operative AF versus

and more late hospital admissions (59% vs 31%,

The majority of patients with longstanding persistent AF

remain in AF if left untreated following cardiac surgery.

Five recent prospective randomized trials of patients with

longstanding persistent AF undergoing mitral valve surgery

showed that the control patients (no AF treatment) had only

a 5% to 33% chance of returning to sinus rhythm at 12

yielded similar results, showing that at two years following

mitral surgery, patients with persistent AF had only a 12%

more heterogeneous group and resumption of sinus rhythm

depends upon other factors such as age, LA dilatation, and

the duration of AF before valve surgery. Two years after

surgery, only 47% of patients with paroxysmal AF were free

Since longstanding persistent AF rarely returns to sinus

rhythm if left untreated, and recent studies indicate that

untreated AF will affect late survival, it is considered advisable

to treat AF at the time of other surgery. The longest

follow-up and largest series with such treatments are using

the classic cut-and-sew Cox-Maze III operation. It is important

to note that these studies have all been retrospective

and observational. Moreover, in these studies, patients were

principally followed for recurrence of symptoms only with

intermittent ECGs. In reports from experienced centers, the

late freedom from recurrent symptomatic AF has been over

follow-up, with a freedom from symptomatic AF of

More recent retrospective studies have documented success

using a variety of different technologies, most commonly

bipolar radiofrequency ablation, for the treatment of

AF with concomitant mitral or other cardiac operations.

844 Heart Rhythm, Vol 4, No 6, June 2007

great variation in the results between different centers. This

can be attributed to many factors, including surgeon experience,

differing lesion sets and the use of different ablation

technologies. The precise lesion set has had the biggest

impact on late results. Generally, more extensive lesion sets

have had better long-term freedom from AF. There has been

one randomized study in which 105 patients undergoing AF

or valve surgery were randomly assigned to three groups:

PV isolation alone or two more extensive LA lesion sets,

both of which included a linear ablation line to the mitral

months. The percent of patients who were in normal sinus

rhythm at last follow-up was 76% in the two more extensive

LA lesion sets, but only 29% in those patients who had PV

isolation only. The poor efficacy of PV isolation alone in

patients with longstanding AF and mitral valve disease has

been supported by a number of other retrospective studies.

PV isolation with a spherical cryoprobe. At last

follow-up, normal sinus rhythm was seen in only 53% of

drugs was present in only 25 patients.

In general, more extensive LA ablation has yielded

higher efficacy, but the rates remain variable (21%–95%).

The success rate for LA ablation has been shown to be

improved for patients undergoing mitral valve surgery if a

lesion is added to the mitral valve annulus as opposed to just

performing PV isolation, particularly for patients with longstanding

studies demonstrated significantly better late results

with biatrial lesion sets when compared to LA lesion

significantly greater rates of freedom from AF

(85%–90%) than compared with those seen in control patients

procedure.

Randomized clinical trials are also available to help

five studies using new ablation technologies including radiofrequency,

microwave and cryoablation, there was a statistically

significant better return to sinus rhythm in those

treated compared to the untreated patients. Success rates

varied between 44% and 94% in these studies. This wide

range of efficacy is likely due to the differing effectiveness

of the energy sources, the differing lesion sets, and the small

number of patients in each series. A biatrial Cox-Maze

procedure was used in only two of the studies. Restoration

of sinus rhythm in the surgically treated patients was associated

with an improved shuttle walk distance, and a reduction

these studies was statistically powered to determine a difference

in survival between the two groups.

The advantages of adding a full Cox-Maze procedure to

concomitant surgery, aside from the resumption of sinus

rhythm, primarily include a reduction in the risk of

risk of stroke at 10 years has been less than 1% in large

of sinus rhythm and atrial systole, or due to

closure or removal of the LA appendage, is not certain, as

both could reduce the risk for stroke. The stroke reduction

from adding a Cox-Maze procedure also applies to patients

who undergo mitral valve surgery, including replacement

using the newer techniques has not yet been demonstrated.

The determinants of failure following surgical treatment

of AF have also been examined in several studies. In general,

larger LA, advanced age, and longer duration of AF

of adding surgical ablation have been low and primarily

associated with collateral damage that has been reported

primarily with unipolar radiofrequency ablation or microwave.

These have included esophageal perforation and coronary

reported after surgical cases, primarily because lesions are

placed at the PV antrum, and not directly on the PVs.

In summary, all patients with AF undergoing other cardiac

surgery should be considered for AF ablation if the risk

of adding the procedure is low, there is a reasonable chance

for success, and the surgery is performed by an experienced

surgeon. A LA procedure should consist of PV isolation

ideally with a connecting lesion to the mitral valve annulus.

A biatrial procedure should be considered for those with

symptomatic AF and those with longstanding persistent AF.

When it can be safely performed, complete occlusion of the

LA appendage should be considered. Since several studies

now indicate that AF is more than just a marker for patients

at high risk, but also is an independent risk factor for

patients, hopefully the late survival of these patients and/or

freedom from adverse cardiac events will be improved, but

this has not been studied prospectively.

There has been a two-decade experience with surgery performed

for lone AF. The term “lone AF” is commonly

employed in the surgical literature to refer to stand-alone

surgery for AF, as compared with AF surgery performed in

conjunction with another type of cardiac surgical procedure

such as mitral valve replacement. This differs distinctly

from the use of the term “lone AF” to refer to a highly

selected subgroup of AF patients who are young and do not

series of stand-alone surgery for AF has been 112

patients who underwent the Cox-Maze procedure. Follow-

2.9 years. Freedom from symptomatic AF was 92% at 14

years, with 80% of patients both free from arrhythmia and

off antiarrhythmic drugs. There was one late stroke in this

group, and 88% of patients were off chronic anticoagulation

Calkins et al. Catheter and Surgical Ablation of AF 845

at last follow-up. The only risk factor for late recurrence

With the introduction of new ablation technology, there

has been renewed interest in less invasive procedures for

stand-alone AF. The only reported case series deal with

either PV isolation alone or a full Maze lesion set using

ablation technology. Most of the reports in the literature are

small, anecdotal and have limited follow-up. Comparison of

outcomes is difficult. Guidelines for reporting clinical results

of surgical procedures for AF have been developed to

been no randomized studies performed comparing the

stand-alone surgical treatment of AF with ablation technology.

The PVs have been isolated either separately or as a large

box lesion incorporating the posterior LA. The first report of

clamp was used for PV isolation on the beating heart

in 27 patients. At three-month follow-up, 91% of patients

were free from AF and 65% were off all antiarrhythmic

drugs.

A larger series of a “box” isolation of all four PVs using

epicardial microwave energy was performed endoscopically

had paroxysmal AF and 17 patients had continuous AF. At

last follow-up, 79.5% of patients were in normal sinus

rhythm. However, 27% of patients needed some type of late

re-intervention. The freedom from symptomatic AF and

re-intervention at last follow-up was only 49%. There was

no operative mortality in either series.

A full Cox-Maze lesion set has been performed with bipolar

ablation technology on 50 patients as a stand-alone procedure.

bypass through either a median sternotomy or a right minithoracotomy.

Thirty-eight percent of the patients had had a

1.3 cm. There was no operative mortality. Mean follow-up

up was 94% with a freedom from antiarrhythmic drugs

and AF at one year of 81%.

In summary, surgery has been performed for 20 years for

AF. It plays an important role in selected patients with AF.

With present ablation technology, surgery can be performed

with low mortality and through limited access incisions.

Programs involved in the stand-alone surgical treatment of

AF should develop a team approach to these patients, including

both electrophysiologists and surgeons, to ensure

appropriate selection of patients.

It is the consensus of this Task Force that the following

are appropriate indications for surgical ablation of AF (Table

1):

1. Symptomatic AF patients undergoing other cardiac surgical

procedures,

2. Selected asymptomatic AF patients undergoing cardiac

surgery in whom the ablation can be performed with

minimal risk,

3. Stand-alone AF surgery should be considered for symptomatic

AF patients who prefer a surgical approach, have

failed one or more attempts at catheter ablation, or are

not candidates for catheter ablation.

The referral of patients for surgery with symptomatic,

medically refractory AF in lieu of catheter ablation remains

controversial. There have been no head-to-head comparisons

of the outcomes of catheter and surgical ablation of

AF. The decision-making in these instances needs to be

based on each institution’s experience with catheter ablation

and surgical ablation of AF, the relative outcomes and risks

of each in the individual patient, and patient preference.

In summary, while surgery for AF has been performed for

two decades, prospective multicenter clinical trials are

needed to better define the relative safely and efficacy of

various surgical tools and techniques. It is critical for future

studies to better document the possible survival benefits of

adjunctive AF surgery. Moreover, surgeons need to adopt

consistent definitions of procedural success and follow-up

methodology, as defined in this consensus document, in

order to compare the different surgical series and the surgical

results to catheter ablation. It is important to note that

virtually all of the historical series reported only the recurrence

of symptomatic AF and have used only intermittent

ECG follow-up. The type and frequency of follow-up also

have varied widely between series. The true success rates of

these procedures are likely to be lower than has been reported.

Even considering these shortcomings, the Cox-Maze

procedure has had good long-term results in the treatment of

both lone AF and AF associated with organic heart disease.

The advent of ablation technology has simplified the surgical

treatment of AF and expanded the indications, particularly

for concomitant AF procedures in patients undergoing

other cardiac surgery. Minimally invasive approaches presently

in development could expand the indications for

stand-alone surgery AF in the future.

It is clear that tremendous progress has been made in the

development of non-pharmacologic therapies for the treatment

of patients with AF. Most of what has been learned

about catheter and surgical AF ablation has been derived

from single center clinical studies. In most cases, these

studies reflect the experience of large academic centers, the

outcomes of which may or may not be replicated by smaller

centers. It is also clear that the inherent design of such

cumulative studies leave many questions unanswered.

At present, very limited data establishing the long-term

impact of catheter or surgical AF ablation on major mor-

846 Heart Rhythm, Vol 4, No 6, June 2007

bidity and mortality are available. Other unresolved questions

include:

1. What are the long-term efficacy outcomes for ablation?

2. What are the comparative success rates of various drug

and ablative techniques?

3. What are the outcomes of AF ablation in patients with

persistent and longstanding AF?

4. Does symptom state at enrollment contribute to trial

outcomes?

5. What is the impact of ablation on atrial size, morphology,

and function?

6. What is the benefit of AF ablation in patients with

varying types of underlying cardiac and noncardiac

disease?

7. Do these interventions have an impact on the long-term

occurrence of stroke or peripheral thrombo-embolic

events?

8. In which patients can warfarin be safely discontinued

following the ablation?

9. Is there acceptable rationale for ablation applied as first

line therapy for AF?

10. Is ablative intervention cost-effective, or is drug therapy

more economically efficient?

11. Beyond placebo effect, what is the relative quality of

life benefit of ablation vs. drug therapy?

12. What is the optimal ablative strategy for treatment of

persistent and longstanding persistent AF?

13. What are the safety and efficacy outcomes of newer

ablation technologies such as cryo, ultrasound, and laser

ablation?

14. What are the safety and efficacy outcomes of ablation

strategies that target complex fractionated electrograms

or autonomic ganglia when used alone or as an adjunctive

procedure?

Moreover, a wide variety of other questions cannot be

answered by available data.

These unresolved issues provide the strong incentive for

conducting additional clinical trials of specific design to

answer critical questions in the ablative arena. These include:

(1) sufficiently powered, randomized mortality studies,

(2) multicenter outcome trials, (3) industry-sponsored

device approval studies, and (4) carefully constructed single

and multicenter registry studies.

While large, multicenter randomized clinical trials are expensive

and require years for completion, they are required

to determine the impact of therapy on mortality and other

long-term outcomes. The randomized trial design is most

likely to provide an unbiased understanding of the outcomes

of ablative intervention and provide information that can be

extrapolated to the largest possible number of patients.

These studies are appropriately held to a higher clinical trial

standard or burden of proof, and should require the comparison

of ablative therapy against best available drug therapy.

At publication however, no such studies have been

conducted.

The Catheter Ablation versus antiarrhythmic Drug for

Atrial Fibrillation (CABANA) Trial, which is currently in

pilot phase, is designed to enroll a sufficiently large number

of patients, and continue for a long enough period of time to

determine if there is a mortality benefit to catheter ablation

of AF. In addition, the CABANA study will investigate

other outcomes of AF ablation and drug therapy including

cardiovascular death, occurrence of disabling stroke, serious

bleeding and cardiac arrest. Rather than comparing any

specific drug therapy against an individual ablative intervention,

this trial will examine pharmacologic rate and

rhythm control strategies and ablative intervention with the

intention of eliminating AF. It is hoped that this study will

collect mortality information and will expand our understanding

of the role of drug and non-drug therapy in those

with advancing age, underlying heart disease, and more

established AF, which will be applicable to a broader range

of patients commonly seen in real life clinical practice.

Finally, this trial will gather information needed for assessing

the impact of therapy on quality of life and health care

resource utilization.

The disadvantage of mortality studies is the accompanying

cost and length of time required for completion. As such,

the science of ablation will be more immediately fostered by

a variety of additional smaller, more agile multicentered

trials. These have the advantage of more quickly providing

answers to more specific questions as considered earlier.

The Radiofrequency Ablation vs. Antiarrhythmic drug for

AF Treatment (RAAFT) trial is one such multicenter study

that is currently underway to further evaluate the safety and

efficacy of RF catheter ablation as first line therapy versus

drug therapy in patients with AF. Similar trials in patients

with various types of AF or underlying disease, as conducted

in consortium research groups, could provide outcomes

data more applicable to a wider range of patients,

without the limitations of single center studies or requisite

randomization against drug therapy.

There currently are a number of prospective, randomized

clinical trials underway to evaluate the safety and efficacy

of AF ablation using investigational catheters and systems

as part of FDA and other regulatory agency approval processes.

Since most of these investigations are industry sponsored,

these studies have almost universally limited enrollment

to patients with paroxysmal AF without underlying

disease. A number of different standard or novel ablation

systems are being evaluated as part of these trials, which

should provide important insight into the safety and efficacy

of catheter ablation. These studies are limited, however, by

short follow-up durations, and restrictive inclusion and exclusion

criteria. Such studies could be substantially stream-

Calkins et al. Catheter and Surgical Ablation of AF 847

lined by the elimination of requisite randomized comparisons

with drug therapy.

The use of registries to collect ablation data should also be

encouraged. The Worldwide Survey of AF Ablation, for

example, has provided an insightful look at ablation outcomes

regard, the registry format discloses outcomes of ablation

therapy as it is actually performed, rather than the way

guidelines suggest it should be. More importantly, registries

could be used to collect a sufficiently large patient experience

to provide efficacy and safety information in the setting

of less common underlying disease, such as hypertrophic

obstructive cardiomyopathy or valvular heart disease,

which is unlikely to be generated in any single center. An

extended understanding of the occurrence of uncommon

complications such as PV stenosis and atrial esophageal

fistula formation are also more likely to be forthcoming

from registries.

Arriving at a clear understanding of the safety and efficacy

of AF ablation is also impeded by the highly variable

definitions and endpoints used in reports of single center

clinical experience. There are substantial differences in

treatment modalities, endpoints of acute and long-term success,

post-ablation blanking periods, follow-up, redo and

cross-over treatments, as well as variability in accounting

for asymptomatic AF, and incomplete accounting for adverse

events occurring beyond the first week of therapy (see

section on Outcomes and Efficacy of Catheter Ablation of

Atrial Fibrillation).

For example, the mean or median duration of follow-up

in published studies has ranged from six months to 2.5

years. Assessment of efficacy has been based either on

symptoms reported by the patient, daily or weekly patientactivated

event monitor recording, Holter monitoring (range

for periods of up to 30 days. Studies have used post-ablation

blanking periods of several weeks to several months. The

definition of a successful outcome also has varied, with

some studies requiring freedom from AF, atrial flutter and

other regular atrial tachycardias in the absence of antiarrhythmic

drug therapy, while other studies require freedom

from AF or a reduction in AF burden independent of drug

therapy as a primary endpoint. Most commonly, freedom

from AF at any particular time point has been derived from

survival curve analysis, whereas other studies report freedom

To overcome these barriers, this Task Force proposes the

following minimum reporting standards for conveying the

results of catheter ablation (Table 2):

1. The general trial design should depend on the questions

being answered.

2. Trials assessing ablation outcomes should not necessarily

require randomization against drug therapy.

3. Randomization against an accepted state-of-the-art ablation

catheter may be sufficient for efficacy and safety

assessment in device approval studies.

4. Sham procedures as a part of these studies are ill advised.

5. Clear description of baseline demographics, including

duration of AF, occurrence of cardioversion within the

context of the duration of that event, the type of AF, LA

size, and the extent of underlying heart disease including

ventricular function.

It is also important to clearly define the clinical characteristics

of the patients enrolled in a clinical trial. As noted

previously in this document, additional detail needs to be

provided concerning the patient’s history of AF. This is

especially important when considering the broad category

of persistent AF. In particular, we would urge investigators

to specify the duration of time patients have spent in continuous

AF prior to an ablation procedure, and also to

specify whether patients undergoing AF ablation have previously

failed pharmacologic therapy and/or cardioversion.

Also suggested are:

6. Adoption of the definitions of paroxysmal, persistent,

and longstanding persistent AF as described earlier.

7. Reporting of data based on a consistent initial postablation

blanking period of three months, even if other

blanking periods are chosen and reported.

8. Reporting of recurrences or events during the postablation

blanking period as “early events.”

9. Clear delineation of extent of underlying cardiac and

noncardiac disease.

10. Requisite ECG documentation of recurrent AF in patients

with persistent symptoms.

11. Event monitor recordings in patients with intermittent

symptoms that are thought to be arrhythmia-related

12. A minimum assessment of symptomatic AF and search

for asymptomatic AF at six months intervals thereafter

using one of the following:

i. Trans-telephonic monitoring for four weeks around

the follow-up interval for symptom-triggered recording

with a minimum of weekly transmissions

to detect asymptomatic events

ii. 24 to 72 hour Holter monitoring

iii. Thirty-day auto triggered event monitoring or mobile

cardiac outpatient telemetry.

Although it is recognized that the endpoints of a

particular study have to be related to the design and

purpose of the study, consistent monitoring techniques

should be employed. It is critical that an indication of

percentage compliance with monitoring requirements

be included in every published study of AF ablation.

The duration of recommended monitoring may vary

depending on the type of AF that was ablated. If the AF

was paroxysmal, optimally multiple 24-hour Holter

monitors, and/or four weeks of monitoring, preferably

848 Heart Rhythm, Vol 4, No 6, June 2007

with an auto-trigger event monitor or by mobile outpatient

cardiac telemetry, is recommended to optimize

identification of asymptomatic episodes. The Task

Force acknowledges that monitoring tools are a work in

progress and may not be uniformly available or practical

for all patients. The suggested monitoring techniques

represent a target standard for evaluating procedural

efficacy.

13. A minimum follow-up duration of 12 months.

14. Recurrences should include both AF and atrial flutter or

atrial tachycardia with the recommendation that the

breakdown of the predominant arrhythmia type be

stated in all reports.

15. Any episode of AF, atrial flutter, or tachycardia of at

least 30 seconds duration that occurs after the blanking

period should be classified as a recurrence even if other

durations are reported.

16. The primary efficacy endpoint of ablation should be

freedom from AF and atrial flutter/tachycardia in the

absence of antiarrhythmic drug therapy. As noted

above, the frequency and patient compliance with monitoring

should be reported.

17. When results are reported as freedom from AF/flutter/

Atrial Tachycardia without antiarrhythmic drugs, the

follow-up period for reporting purposes should begin 5

half lives after the antiarrhythmic drug has been

stopped or at least three months after stopping amiodaron.

18. Because of the clinical relevance of this information, the

secondary endpoint of freedom from AF and atrial flutter/

tachycardia in the presence of previously ineffective antiarrhythmic

therapy also should be clearly stipulated.

19. Patients experiencing recurrent AF with a subjective

improvement in AF burden should not be included in

the category “free of AF” after the ablation procedure,

although the percentage of patients in this category may

be noted to provide readers with an understanding of

the differing levels of improvement that patients can

report after AF ablation.

20. Because of the importance of symptomatic AF as a

primary indication for AF ablation, studies should incorporate

standardized tools to allow assessments of

quality of life.

21. All studies of AF ablation should include a complete

reporting of major complications. A major complication

is defined as a complication that result in permanent

injury or death, requires intervention for treatment,

or prolongs or requires hospitalization (Table 2).

The Task Force believes that having all categories of

outcome reported allows the readers to determine the relevant

outcome for themselves and may provide important

insights into the role of AF ablation in AF management and

also into the pathogenesis of AF. However, the gold standard

for assessing the efficacy of new techniques and technology

should remain freedom from AF/flutter/tachycardia

of greater than 30 seconds duration off all antiarrhythmic

drugs.

Although Kaplan-Meier analyses are commonly used to

report outcomes of AF ablation, particularly in randomized

clinical trials, this methodology may underestimate the true

effectiveness of AF ablation. This underestimation results

from the fact that isolated recurrences of AF following

catheter ablation beyond the blanking period are commonly

observed. The members of this writing group accept the

notion that patients with these types of sporadic recurrences

may go on to achieve excellent long-term AF control and

clinical benefit from the procedure. Because this pattern of

benefit will be missed by a Kaplan-Meier analysis, it is

recommended that other alternative and/or secondary endpoints

be reported in clinical trials. We would therefore

propose that clinical trials also report AF/flutter/tachycardia

the method used for monitoring in the treatment and control

arms be reported as part of this type of analysis.

It is anticipated that well designed clinical trials will continue

to provide a solid evidence base upon which to formulate

practice guidelines in the future. The above reporting standards

will lead to sufficient comparability to facilitate that goal.

A comment regarding the funding of clinical trials is

consistent with the overarching goals of this AF Ablation

Guideline document. While the value of programs ensuring

funding of basic investigation in cardiac electrophysiology

is central to understanding arrhythmogenesis, funding of

translational and clinical studies provides the critical means

of extending and applying that information to the patient

care arena. Industry, third party payers and the NIH should

be strongly encouraged to provide the increasingly critical

dollars needed to conduct these trials. The academic community

should solidly support the paradigm of partnerships

between these groups and private foundations, and clinicians

should extend their patient advocacy to the level of

these agencies and organizations to lobby for the necessary

support for funding meritorious trials. This requires more

than passive support. It mandates active intervention from

the cell lab to the clinic and from industry to insurance

companies.

Catheter and surgical ablation of AF are commonly performed

procedures throughout the world. This document

provides an up-to-date review of the indications, techniques,

and outcomes of catheter and surgical ablation of AF. Areas

for which a consensus can be reached concerning AF ablation

are identified. It is important to note that this statement

summarizes the opinion of the Task Force members based

on their experience and a review of the literature. It is also

important to note that when we use the term “consensus” in

this document, this does not mean that there was complete

agreement among all Task Force members. It is our hope

that this document can improve patient care by providing a

foundation for those involved with ablation of AF. It is

recognized that this field continues to evolve rapidly and

Calkins et al. Catheter and Surgical Ablation of AF 849

that this document will need to be updated. Successful AF

ablation programs optimally should consist of a cooperative

team of electrophysiologists and surgeons to ensure appropriate

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during concomitant cardiac surgery. Ann Thorac Surg 2005;80:210–215.

339. Ninet J, Roques X, Seitelberger R, Deville C, Pomar JL, Robin J, Jegaden O,

Wellens F, Wolner E, Vedrinne C, et al. Surgical ablation of atrial fibrillation

with off-pump, epicardial, high-intensity focused ultrasound: results of a multicenter

trial. J Thorac Cardiovasc Surg 2005;130:803– 809.

340. Gaita F, Riccardi R, Caponi D, Shah D, Garberoglio L, Vivalda L, Dulio A,

Chiecchio A, Manasse E, Gallotti R. Linear cryoablation of the left atrium

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and valvular heart disease: correlation of electroanatomic mapping and longterm

clinical results. Circulation 2005;111:136 –142.

341. Geidel S, Ostermeyer J, Lass M, Betzold M, Duong A, Jensen F, Boczor S, Kuck

KH. Three years experience with monopolar and bipolar radiofrequency ablation

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2005;27:243–249.

342. Isobe N, Taniguchi K, Oshima S, Kamiyama H, Ezure M, Kaneko T, Tada H,

Adachi H, Toyama T, Naito S, et al. Left atrial appendage outflow velocity is

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343. Tada H, Ito S, Naito S, Hasegawa Y, Kurosaki K, Ezure M, Kaneko T, Oshima

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858 Heart Rhythm, Vol 4, No 6, June 2007

Author Disclosures

Task Force Members Research Grants Fellowship Support

Speakers’ Bureau/

Honoraria Ownership Interest

Consultant/

Advisory Board Other

Josep Brugada, MD None Boston Scientific Boston Scientific

Medtronic

St Jude Medical

None Biotronik

Boston Scientific

None

Hugh Calkins, MD None Bard EP

Boston Scientific†

Medtronic†

Atricure

Bard EP

Biosense Webster

Boston Scientific

Medtronic

Reliant

None Ablation Frontiers

Atricure

Bard EP

Biosense Webster

Boston Scientific

Cyberheart

CryoCor

Medtronic

ProRhythm

Sanofis Aventis

None

Riccardo Cappato, MD Bard EP†

Biosense†

Boston Scientific†

ELA Medical†

St Jude Medical†

Biosense†

Boston Scientific†

ELA Medical†

St Jude Medical†

Biosense†

Boston Scientific†

ELA Medical†

St Jude Medical†

Medtronic†

Boston Scientific†

Cameron Health†

Bard EP†

Biosense†

Boston Scientific†

ELA Medical†

St Jude Medical†

None

Shih-Ann Chen, MD Boston Scientific†

St Jude Medical†

None Bard EP

Biosense Webster

St Jude Medical

None None None

Harry J.G. Crijns, MD Medtronic† Boston Scientific

Medtronic

St Jude Medical

Astra Zeneca

Biosence

MEDA

Sanofi Aventis

St Jude Medical

None Astra Zeneca

Biosense Webster

MEDA

Sanofi Aventis

None

Ralph Damiano, MD Atricure†

Boston Scientific

Medical CV

None Cryocath

Edwards Lifesciences

None Atricure†

Medtronic†

Medical CV

None

D. Wyn Davies, MD None None None Medtronic†

ProRhythm

Ablation Frontiers

CryoCath

St Jude Medical

Medtronic† (Salary)

David Haines, MD Bard EP

Boston Scientific

Cardiofocus

ProRhythm

None None nContact Bard EP

Toray

nContact

(Intellectual

Property Right)

Michel Haissaguerre, MD Johnson & Johnson†

Bard EP†

None None None Johnson & Johnson†

Bard†

Johnson & Johnson†

(Royalties)

Bard EP† (Royalties)

Yoshiko Iesaka, MD None None None None None None

Warren M. Jackman, MD None None Atricure†

Biosense Webster†

Cardiofocus†

ProRhythm†

Stereotaxis†

None Biosense Webster†

Stereotaxis†

ProRhythm†

Cardiofocus†

Atricure†

CardioFocus†

Pierre Jais, MD None None Bard EP

Biosense Webster

Philips EP Medical

St Jude Medical†

SORIN

None Biosense Webster

Philips EP Medical

St Jude Medical†

SORIN

None

Hans Kottkamp, MD None None Biosense Webster†

St Jude Medical†

None Biosense Webster

St Jude Medical†

None

Karl Heinz Kuck, MD None None None Biosense Webster

Stereotaxis†

Biosense Webster

St Jude Medical

None

Bruce Lindsay, MD None Boston Scientific†

Medtronic†

None None Boston Scientific†

(terminated in May

2006)

Stereotaxis

(terminated in May

2006)

None

Francis Marchlinski, MD Biosense Webster†

Boston Scientific†

Medtronic†

St Jude Medical†

Biosense Webster†

Boston Scientific†

Medtronic†

St Jude Medical†

Biosense Webster

Boston Scientific

Medtronic

St Jude Medical

None Biosense Webster

GE Healthcare

None

Patrick McCarthy, MD None None Atricure Medical CV† Boston Scientific†

Medical CV†

Medtronic†

None

Calkins et al. Catheter and Surgical Ablation of AF 859

Author Disclosures

Task Force Members Research Grants

Fellowship

Support

Speakers’ Bureau/

Honoraria Ownership Interest

Consultant/

Advisory Board Other

J. Lluis Mont, MD Atricure

Boston Scientific

Johnson & Johnson

Medtronic

St Jude Medical

None Boston Scientific

Medtronic

St Jude Medical

None Boston Scientific

Johnson & Johnson

Medtronic

St Jude Medical

None

Fred Morady, MD None None Biosense Webster

Boston Scientific

Medtronic

Reliant

St Jude Medical

Ablation Frontiers† None Ablation Frontiers†

(Intellectual

Property Right)

Koonlawee Nademanee, MD Biosense Webster†

Medtronic†

None Biosense Webster

Boston Scientific

Medtronic

St Jude Medical

None Biosense Webster

St Jude Medical

Biosense Webster†

(Royalties)

Andrea Natale, MD Biosense Webster†

Boston Scientific

Medtronic†

St Jude Medical†

None Biosense Webster

Boston Scientific

GEE

Medtronic

St Jude Medical

Signalife

None None None

Douglas Packer, MD Biosense†

Boston Scientific

CardioFocus†

CryoCath†

ESI†

St Jude Medical†

Siemens†

Symphony Medical†

Transurgical†

None Biosense† St Jude Medical† Bard EP

Boston Scientific†

CardioFocus†

CryoCor

Hansen Medical

IRM†

Medtronic

Reliant Pharma

St Jude Medical†

Siemens†

Symphony Medical†

Transurgical†

ESI†

Carlo Pappone, MD None None None None Biosense Webster

St Jude Medical

Stereotaxis

None

Erik Prystowsky, MD Boston Scientific†

Medtronic†

St Jude Medical†

Sanofi-Aventis† Cardionet†

Stereotaxis†

Bard†

Biosense Webster

Medtronic†

Sanofi-Aventis†

Stereotaxis†

None

Antonio Raviele, MD None None Biosense Webster None Biosense Webster

Medtronic SQDM

None

Jeremy Ruskin, MD None Boston Scientific†

Medtronic†

St Jude Medical†

Boston Scientific

St Jude Medical

Cameron Health†

CardioOptics InnerPulse†

Astellas†

AstraZeneca†

Biosense Webster†

Cardiofocus

CV Therapeutics†

Cryocath

Medtronic†

Pfizer†

Sanofis Aventis†

Stereotaxis†

None

Richard Shemin, MD None None None None St Jude Medical† None

A relationship is considered to be “modest” if it is less than “significant” under the preceding definition.

†Significant. A relationship is considered to be “significant” if (1) the person receives $10,000 or more during any 12–month period or 5% or more of the person’s gross income;

or (2) the person owns 5% or more of the voting stock or share of the entity or owns $10,000 or more of the fair market value of the entity.

860 Heart Rhythm, Vol 4, No 6, June 2007

Peer-Review Disclosures

Reviewer (Organization) Research Grants

Fellowship

Support

Speakers’ Bureau/

Honoraria

Ownership

Interest

Consultant/

Advisory Board Other

Carina Blomstrom-Lundqvist, MD (EHRA) None None None None None None

Charles Bridges, MD (STS) None None None None Bayer None

Christopher Fellows, MD (ACC) Boston Scientific

St. Jude Medical

None Boston Scientific

St. Jude Medical

None Boston Scientific

St. Jude Medical

None

A. Marc Gillinov, MD (STS) Medtronic† None None AtriCure† AtriCure

Boston Scientific

Edwards Lifesciences†

Medtronic

St. Jude Medical

Kapp Surgical

Richard Hauer, MD (ECAS) None None None None None None

Gerhard Hindriks, MD (EHRA) None None Biotronik None Biosense Webster

Biotronik

St. Jude Medical

Bard EP

Biosense Webster

Jose Jalife, MD (HRS) None None None None None None

Jonathan Kalman, MD (HRS) Medtronic†

St Jude Medical†

Biosense Webster

Johnson & Johnson

Medtronic†

St Jude Medical†

Biosense Webster

Johnson & Johnson

Medtronic†

St Jude Medical†

Medtronic†

St Jude Medical†

Peter Kowey, MD (ACC) None None None None None None

Prof. Samuel Levy, MD (ECAS) None None None None None None

William Maisel, MD (AHA) None None None None U.S. FDA None

James Maloney, MD (HRS) None None Boston Scientific

Medtronic

Phillips EP Medical

Reliant Pharmaceuticals

St. Jude Medical

None Boston Scientific

Medtronic

Philips EP Medical

Reliant Pharmaceuticals

St. Jude Medical

None

John M. Miller, MD (HRS) None None None None Biosense-Webster

Boston Scientific

Medtronic

St. Jude Medical

Stereotaxis

Boston Scientific†

Medtronic†

St. Jude Medical†

Jeffrey Olgin, MD (AHA) St. Jude Medical† None Boston Scientific†

Medtronic†

St. Jude Medical†

None None Boston Scientific†

Medtronic†

St. Jude Medical†

Richard Page, MD (ACC/AHA/HRS) Proctor and Gamble None None None Berlage

Sanofi Aventis

John Locke Trust

Julian Perez-Villacastin, MD (EHRA) None None None None Boston Scientific

Cordis

Medtronic

St. Jude Medical

None

Martin Schalij, MD (EHRA) None None None None None None

Richard Schilling (ECAS) None None None None Biosense Webster

Medtronic

St. Jude Medical

Biosense†

Boston Scientific†

Mel Scheinman, MD (AHA) None None Boston Scientific None None None

Claudio D. Schuger, MD (ACC) Biosense

Boston Scientific

Medtronic

None Boston Scientific None None None

Gordon Tomaselli, MD (AHA/HRS) None None None None None None

Cindy Tracy, MD (ACC) None None None None None None

Al Waldo, MD (ACC) Reliant† Biosense Webster

Biotronik

ChanTest

CryoCor

Daiichi

GlaxoSmithKline

Reliant Pharmaceuticals

Sanofi-Aventis

St. Jude Medical

A relationship is considered to be “modest” if it is less than “significant” under the preceding definition.

†Significant. A relationship is considered to be “significant” if (1) the person receives $10,000 or more during any 12–month period or 5% or more of the person’s gross income;

or (2) the person owns 5% or more of the voting stock or share of the entity or owns $10,000 or more of the fair market value of the entity.

Calkins et al. Catheter and Surgical Ablation of AF 861

(Last updated 11/16/08)

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