2014 Boston AF Symposium

Dr. David Keane

Catheter Ablation Complications: In-depth Review and Comparison with Antiarrhythmic Drug Therapy

by Steve S. Ryan, PhD, July 11, 2014

Under the topic “Quality and Safety in the Interventional EP Lab” Prof. David Keane of St. Vincent’s University Hospital, Dublin Ireland gave a presentation entitled “Complications Associated with Catheter Ablation for AF—Overview 2014.”

Keep in mind: This presentation is targeted at cardiologists who know the complication rate of catheter ablation is low, about 1%-2%. As patients, to evaluate this rate you need a point of reference. For example, the complication rate of the common Appendectomy is about 18%. Catheter ablation is a low-risk procedure comparable to a routine Tubal Ligation (1%–2% risk rate), though it’s not risk-free.

While Dr. Keane’s presentation covers an extensive list of possible complications, most catheter ablation complications are, in fact, minor—such as bleeding and bruising at the groin. Most are resolved in two to three weeks.

 Highest With Low-Volume

The most important information for A-Fib patients presented at this year’s Symposium was the observation that: The biggest predictor of in-hospital complications for Medicare patients was A-Fib ablation volume of less than 25 per year.

[This makes all too much sense. An operator performing such a small number of Pulmonary Veins Ablation/Isolations (PVIs) a year may not have enough practice to develop and maintain proficiency in a procedure that is operator-skill dependent, and may never develop the experience necessary for proficiency. In a Clinical Competency Statement by the ACC/AHA/ACP, “It is recommended that physicians who perform ablations maintain a volume of 20 to 50 ablations/year.”¹}

A more surprising research finding was that “more than 81% of…A-Fib ablation procedures in the US were performed by operators with an A-Fib volume of less than 25 [Medicare patients] per year.”

[This astounding statistic is a wake-up call for all A-Fib patients. The vast majority of A-Fib ablations are performed by operators who are probably the least proficient and certainly have the highest complication rates. As A-Fib patients, we have to make every effort to be treated by high volume centers and operators. In general, high volume doctors wouldn’t be performing so many A-Fib ablations if they weren’t good and highly successful, with lower complication rates.

But how can I find out how many ablations my EP does?” Right now all I know to do is call your EP’s office and ask how many PVIs they do per year. A more verifiable (and less socially awkward method) would be to have a list of all the EPs in your state and how many PVIs they do. Such a list could be made using Medicare data. I intend to seek a grant to develop such a list and publish it on A-Fib.com.]

 Complication Rates

Catheter Ablation vs Antiarrhythmic Drugs (AADs) 

Complications from A-Fib ablation should be viewed in perspective. How does the success and complication rates of catheter ablation stack up against a lifetime on antiarrhythmic drugs (AADs)?

In what may be the first systematic literature review and meta-analysis of clinical studies of Radiofrequency Ablation (RFA) vs. Antiarrhythmic Drugs (AADs), the reviewers looked at studies from 1990 to 2007. [Note: RFA wasn’t in use until the mid-1990s.] Included were sixty-three RFA studies and 34 AAD studies.²

Meta-Analysis Findings

Radiofrequency Ablation (RFA) had a higher efficiency rate and a lower rate of complications than AAD Therapy.

From 1990-2007, the single procedure success rate for Radiofrequency Ablation (RFA) without need of post-op AAD therapy was 57% (today’s success rates are in the 70%-85% range),^3,4,5 multiple procedure success rates without post-op AADs were 71% (today’s success rates are closer to 90%), and the multiple procedure success rate with post-op AADs was 77%.

The success rate for AAD therapy alone was 52%.

The meta-analysis included five AADs: amiodarone, dofetilide, sotalol, flecainide, and propafenone. Amiodarone was the most effective.

[Note: Amiodarone is the most toxic and dangerous of the five AADs and is usually prescribed only for short periods of time and under close supervision for bad side effects. Amiodarone may affect your lungs, eyes, thyroid, liver, skin, heart and nervous system. If amiodarone had been excluded from this study, the success rate for AADs would have probably been even lower than 52%. For more see my article: Amiodarone: Most Effective and Most Toxic ].)

Adverse Events Findings

Adverse events for the AAD studies were 30% vs. 5% for catheter ablation [An ‘adverse event’ is any undesirable patient experience from the use of a medical product. In the US, adverse events are reported to the FDA.]

The overall death rate for AAD therapy was 2.8% (Sudden death was 0.6%, treatment-related death was 0.5%, non treatment-related death was 1.3%). There were no procedure-related deaths in the Radiofrequency Ablation (RFA) studies, though the overall death rate was 0.7% (in-hospital deaths).

Other adverse events from AAD therapy were:

•  CV (cardiovascular) Events 3.7%
•  Bradycardia 1.9%
•  GI (Gastrointestinal problems) 6.5%
•  Neuropathy 5.0%
•  Thyroid Dysfunction 3.3%
•  Torsades 0.7%
•  Q-T prolongation 0.2%

[Most adverse events associated with antiarrhythmic drugs (AADs) are life altering and permanent. For example, bradycardia requires a pacemaker.

Whereas the worst complications from catheter ablation are generally short term and not permanent. For example, when tamponade is repaired, the heart usually returns to normal.

In general, it appears it’s safer to have an ablation than to not have one and live a life-time on AADs (this is one of the hypotheses being tested in the ongoing CABANA trial.]

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In general, it appears it’s safer to have an ablation than to not have one and live a life-time on AADs.

 Many Can’t Tolerate AADs

Because of adverse events, 10.4% of patients discontinued antiarrhythmic drugs (AADs), 13.5% discontinued AADs because of treatment failure, 4.2% just didn’t take the ADDs. The overall discontinuation rate of AADs was almost 30%.

[This study did not look at the other approach to drug therapy to treat A-Fib. Rate Control drugs try to control the A-Fib heart rate while leaving you in A-Fib. That’s generally a recipe for disaster. Leaving patients in A-Fib overworks the heart and leads to remodeling and fibrosis which also increase the risk of stroke. As Mellanie True-Hills of StopAfib.org asked, “Should we leave folks in A-Fib long term, especially the non-elderly? Between the risk of heart failure, and fibrosis from long-term remodeling increasing stroke risk, could staying in A-Fib long-term be a death sentence?”]

 Dr. Keane’s Extensive List

 Potential Ablation Complications

Dr. Keane described every conceivable complication that could come from a catheter ablation, in order to give the attending doctors a heads-up on how to deal with even the rarest complication. [Some were so unusual and rare I had never heard of them.]

For example, a small aberrant branch of the femoral artery may be found on top of the femoral vein. When inserting a catheter into the femoral vein, one could nick this femoral artery branch. When the catheter is removed at the end of an ablation, there could be bleeding and a hematoma at the site. Doctors need to be prepared for this complication and repair the nick with a suture or patch. [For patients, some of these complications are so rare they aren’t worth worrying about. But doctors do worry and need to be ready for anything.]

Patent Foramen Ovale (Hole in the Septum)

Some ablation patients (around 20%) have a naturally occurring open hole (called ‘patent foramen ovale’) between the right and left atrium. It’s easy for doctors to go through this opening when inserting a catheter from the right atrium into the left atrium. But unlike a normal transseptal puncture hole, when the catheter is withdrawn, this hole may stay open. At a later date it may be necessary to insert a plug into this open hole [as was the case for the New England Patriots’ linebacker Tedy Bruschi]

[Rarely a normal transseptal puncture hole may not close up entirely after an ablation (called an Atrial Septal Defect), especially when the largest catheters are used or when a double transseptal puncture is performed.]

Tamponade

Blood or fluid that collects in the pericardium, the sac around the heart, is called a Tamponade. This pressure can prevent the heart from beating and feels like one is being strangled. Doctors need to drain this fluid or blood from the pericardium.

This is probably the most dangerous complication from a catheter ablation. If an EP or the hospital staff aren’t careful, this could lead to serious complications, even death. Serious tamponade is more often produced by inexperienced EPs who are more apt to apply too much pressure when making ablation burns, and are also more likely to miss the tell tale signs of a tamponade in its early stages where it’s fairly straight forward and relatively easy to repair with little or not danger or long term effects. When a tamponade is fixed, there are usually no lasting problems. Dr. Keane explained how doctors can detect a tamponade by using echocardiography.

Entrapped Catheters

Another very rare complication is entrapped catheters. For example, a circular mapping catheter which has a larger circular surface than an ablation catheter, could possibly get stuck in a vein or elsewhere. Dr. Keane described maneuvers to dislodge it. In a worst case scenario, surgery might be required.⁶

Atrio-Esophageal Fistula

The most dreaded complication possible with catheter ablation is Atrio-Esophageal Fistula, but happily it’s also the most rare. When a catheter makes an RF burn in the back of the heart near the esophagus, the heat from the catheter may damage the esophagus wall which can later be eroded by gastric acids allowing blood from the heart to leak into the esophagus.

This is a very rare complication (less than one in over 1000 cases) that can be fatal. It usually takes a period of 2-3 weeks for a fistula to develop. During this time gastric acids eat through the esophageal area weakened by heat from the RF catheter. It’s the most difficult complication to recognize early and may not be detected during procedural hospitalization.

Most doctors and centers take great precautions to prevent Atrio-Esophageal Fistula, for example, by putting a temperature probe down the esophagus to measure heat and stopping the ablation if heat rises. Doctors also prescribe proton pump inhibitors to be taken for 2-3 weeks after an ablation in order to prevent gastric acids from eroding the esophagus. [Patients can do this on their own by using over-the-counter proton pump inhibitors like Nexium or Prilosec.] Added 9/11/17: Cecelia writes that taking the Proton Pump Inhibitor omeprozole (Prilosec) caused her muscle weakness, weak legs and arms (and anxiety). She took it for six weeks during her blanking period after her ablation to protect the esophagus. Pantoprozole (Protonix) seemed to have the same effect on her. Muscle weakness is listed as a possible side effect of reflux meds.  

Stroke

If you have developed an A-Fib-related clot prior to your ablation (usually in the Left Atrial Appendage), a catheter ablation may dislodge it and cause a stroke. To prevent this, some centers check for clots by using a Transesophageal Echocardiogram (TEE) or CT before the ablation. If they find one, you take blood thinners to dissolve it before having your catheter ablation.

But a stroke can also occur from an ablation itself. That’s why during an ablation you receive high doses of blood thinners like heparin. [That’s also why it takes so long for the insertion points in your groin to heal after an ablation.] The risk of a stroke during an ablation is small, less than 0.5% according to figures from the French Bordeaux group.⁷

PV Stenosis

Pulmonary Vein Stenosis is a swelling, constriction or narrowing of the pulmonary vein opening into the left atrium. This swelling can restrict blood flow from the lungs into the heart. This was an all-too-common problem in the early days of catheter ablation when RF burns were actually made inside the PVs causing swelling and stenosis.

But nowadays most EPs ablate far outside the PV openings (“Wide Area Antrum Isolation”) with the result that PV Stenosis is much less common. But Dr. Keane asserts “PV Stenosis hasn’t gone away and is likely underestimated.”

Stiff Left Atrial Syndrome

A rare but potentially significant complication is Stiff Left Atrial Syndrome (also seen after surgical approaches using multiple lesion burns in the left atrium). The ability of the left atrium to contract is compromised which also causes pulmonary hypertension, shortness of breath, and congestive heart failure. Unlike most catheter ablation complications, this is most often a permanent and debilitating complication.

Dr. Keane described a study of 1,380 consecutive patients who had a catheter ablation. After their ablation, 1.4% developed Stiff Left Atrial Syndrome. Most of them were non-paroxysmal (71%). Pre-ablation, these patients had severe Left Atrium scarring and were more likely to have sleep apnea.⁸

In non-paroxysmal A-Fib cases, more ablation lines and burns are often made. (Most ablations of paroxysmal A-Fib are relatively simple, A-Fib is stopped by simply isolating the pulmonary veins). In a “stepwise approach”, after isolation of the pulmonary veins, ablation lines may be created in the roof, anterior wall, septum, mitral isthmus and other areas as well as burning or isolating areas of fractionated atrial electrograms, rotors and focal sources. These additional RF burns can produce scarring and fibrosis of the atrial wall. [For more about isolation burn methods, read my 2014 BAFS report about http://europace.oxfordjournals.org/content/early/2013/02/28/europace.eut038.full.pdf which greatly reduce the amount of burns necessary.]

Of the study participants who developed Stiff Left Atrial Syndrome (1.4%), most had a lot of scarring to begin with. Then they probably received more ablation lines and burns than in a normal PVI. These additional burns and scarring could be responsible for weakening their ‘atrial kick’ (strength of the atrial contraction) and producing Stiff Left Atrial Syndrome.

[As patients we are indebted to Dr. Keane for identifying a new potentially very serious complication from catheter ablation. Patients with non-paroxysmal A-Fib who have probably had A-Fib for a significant time and/or who already have a lot of scarring in their heart, need to be warned that there is a real (1.4%) risk of weakening or even losing the function of their left atrium by excessive ablation burns (also by surgery). Losing the strength of the left atrial contraction (atrial kick) is probably as bad as being in persistent A-Fib. The whole point of a catheter ablation is to restore left atrial function, to get people back into normal sinus rhythm.] 

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Phrenic Nerve Injury (PNI)

There are two phrenic nerves (left and right). They originate in the neck and pass down between the heart and the lungs to reach the diaphragm, the primary muscle involved in breathing. Contraction of the diaphragm muscle permits expansion of the chest cavity and inhalation of air into the lungs. [In the early trials of CryoBalloon ablation, the freezing of a Pulmonary Vein would also freeze the adjacent Phrenic Nerve. Doctors learned to pace the Phrenic Nerve during a CryoBalloon ablation and to stop the freeze if the Phrenic Nerve and diaphragm was affected. The Phrenic Nerve basically would then defrost and return to normal.]

Dr. Keane cited a study of ablation in 3,755 patients: 18 (0.48%) developed PNI, 12 (66%) had complete recovery of their Phrenic Nerve function over time. [A brief Google search reveals several centers doing Phrenic Nerve reconstruction surgery.]

Vagus Nerve Injury

The Vagus Nerve comes from the brain and extends to the abdomen via various organs including the heart. If the Vagus Nerve is injured, it can result in abdominal bloating, pain, nausea, early or easy satiety, and weight loss.⁹ [This is another rare complication I had never heard of before.]

Bronchial Damage and Coughing Up Blood Caused by Cryoballoon Ablation

Anyone coughing up blood after a PVI may have a ruptured small blood vessel caused by coughing (which isn’t serious), or a bronchial infection which needs to be treated, as with antibiotics. ¹⁰[Another relatively rare complication.]

Aortic “Injury”

Aortic “Injury” is a very new discovery. When the Left Atrium (LA) is heated during a Radio Frequency PVI burn, this heat can reach the Aorta which may be next to the Left Atrium (LA). This results in what doctors term “aortic wall enhancement” as determined by MRI examination. They are careful not to use the term “damage,” because they haven’t determined if the Aorta suffers permanent damage or if it heals itself after a PVI and returns to normal.¹¹ [Probably the Aorta does heal itself. Serious Aorta damage would result in massive bleeding and probably death, which we haven’t seen.]

Silent Cerebral Lesions

In the clinical trials of newer mesh-type catheters, MRI exams found silent cerebral lesions. These were lesions that didn’t seem to cause any immediate problems and which mostly disappeared over time. But doctors are somewhat nervous and don’t want to produce any cerebral lesions, even if they are “silent” for now. According to Dr. Keane, “Silent Cerebral Events are underestimated, and long-term clinical consequences, if any, are unknown.”

 Most Discussed Complications

Of the twelve complications detailed above, the most discussed by doctors are:

•  Atrio-Esophageal Fistula (very rare, but often fatal)
•  Stroke
•  Cardiac Perforation – Tamponade
•  PV Stenosis/Occlusion
•  Vascular – femoral

 Unforseen Complications

There are unforeseen complications—things that can happen any time you go into a hospital.

Imaging problems:

•  a TEE may irritate or even puncture the esophagus and cause infection
•  X-Ray related damage
•  aspiration of Barium paste affecting respiration

General Anesthesia (GA) & Conscious Sedation problems:

•  endotracheal tube discomfort, vocal cord and dental injury
•  adverse drug reactions
•  becoming overheated
•  aspiration pneumonia

Vascular problems:

• hematoma (blood swelling)
•  hemorrhage
•  femoral discomfort and numbness

 Post-Op Complications

During the healing process, catheter ablation patients may experience some or all of the following temporary complications:

•  Reduced mobility
•  Low blood pressure for a few days
•  Reduced energy for less than a week
•  Possible deep vein thrombosis
•  Increased awareness of heart action and a faster rate (+10-15 bpm) or ectopic beats
•  Need to pass a lot of urine (because of receiving a lot of fluids during the ablation procedure from the irrigated tip ablation catheter)
•  Migraine

[Although not on Dr. Keane’s list, additional temporary complications may include:

•  Chest pains (probably from an irritated pericardium due to radiated RF heat)
•  Low grade fever
•  Bruising and hematoma at the catheter insertion sites]

 Complications Rate Decreases

As Number of Ablations Triple

Dr. Keane showed that catheter-related complications from 2002 to 2010 have significantly decreased as A-Fib ablation techniques and experience have improved, while the number of ablations has more than tripled.

In 2002, catheter-related complications were nearly 7% but fell by 2010 to less than 2%. In particular, TIAs and PV stenoses complication rates were reduced to one-half or one-third.¹²

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 In-Hospital Deaths

Associated with Lower Volumes

In a study of Medicare data on catheter ablations from 2001-2006, there were 25 “in-hospital deaths” out of 6,065 cases (0.41%). This is a very high and disturbing death rate compared to most other studies.

But this finding should be interpreted with caution. Medicare data doesn’t list causes of death or whether a death was procedure related, though one would think that most of the deaths would be directly or indirectly associated with the ablation procedure, as compared to other hospital causes of death like sepsis. [Medicare also does not currently have a specific billing code for A-Fib ablation—a strange oversight considering how many people have A-Fib.] However, the study did conclude that in-hospital death was significantly associated with hospitals who performed a lower volume of catheter ablations.

There was a 3% rate of perforation/tamponade. (Of the 25 patients who died, 12% experienced perforation/tamponade and 12% experienced collapsed lung.)

Another surprising finding was that the most elderly (85 and older) had a significantly lower rate of complications (2.5%) than younger patients (in the US, patients become eligible for Medicare at age 65). “There is at present no clear explanation for this finding.”¹³ These very elderly patients were less likely to have a documented history of smoking, obesity, or hyperlipidemia (high cholesterol and lipids) and were significantly more likely to be female. [One possible explanation is that the most elderly are predominantly female who live longer than men and tend to be healthier and have more healthy life styles.]

Somewhat different results of in-hospital deaths were found in a study of California data from 2005 to 2008 of 4,156 patients who had an A-Fib ablation. There was one death and 104 cases of Perforation/Tamponade (0.02%). But 9% were readmitted within 30 days. In this study older age, female gender, prior A-Fib hospitalizations and hospitals with lower volumes of catheter ablations were associated with a higher risk of complications.¹⁴ [Female gender may be more related to age since females tend to live longer than men.]

 Age Does Matter

Dr. Keane cited another large study of 15,423 Medicare patients with A-Fib who had a PVI and were followed for a year (July 2007 through December 2009). Of the total, 1,912 of these patients were over 80 years old. All-cause mortality was significantly higher (almost 10%) in the over 80 group. Stroke rate was also higher.¹⁵ Most Ablations done by low-volume operators produced the most complications.

The biggest independent predictor of in-hospital complications was operator volume of less than 25 ablations per year.

In a study of 93,801 A-Fib ablations performed from 2000 to 2010, “more than 81% of…A-Fib ablation procedures were performed by operators with an annual A-Fib volume of less than 25.”¹⁶ In this study the overall frequency of complications was 6.29% (but this includes minor complications like bleeding at the insertion sites).

Women had higher complication rates than men (7.51% vs 5.49%). “In-hospital deaths” was 0.42% as in the previously mentioned Medicare study. The over-80 age group had more complications. The biggest independent predictor of in-hospital complications was annual operator volume of less than 25 catheter ablations per year. In this study the complication rate remained steady in low volume operators over the years.

 Take-Aways

Predictors of A-Fib Ablation Complications are:

•  age (elderly)
•  female gender (but this may be more related to age since females live longer than men)
•  diabetes mellitus
•  previous stroke
•  heart failure
•  vascular disease
•  renal disease
•  anemia
•  operator with lower procedural volume

The following technical improvements may reduce complication rates:

•  Contact Force Sensing catheters
•  Tissue temperature monitoring
•  Real time lesion formation monitoring and imaging
• Technologies for remote site supervision/interaction for start-up PVI programs

Editor’s Comments:

Danger of Low Volume Operators

We’re indebted to Dr. Keane not only for his exhaustive list of every conceivable complication from a PVI catheter ablation procedure, but more importantly for his research finding that complications come mostly from low volume operators (<25/year), and that 81% of all ablations are performed by low volume operators. As patients, we have to make an effort to find high volume operators and experienced hospitals. (I intend to try to put together such lists by state.)

Stiff Left Atrial Syndrome Identified

We’re also indebted to Dr. Keane for identifying a rare but potentially debilitating complication not even mentioned in other studies of A-Fib procedure complications—Stiff Left Atrial Syndrome. Though one tends to see this in the more extensive surgical operations for A-Fib, it can happen in RF ablation as well where many ablation lines have to be made. Patients with non-paroxysmal A-Fib who may already have a lot of scarring and fibrosis in their hearts due to long-time A-Fib, need to be warned that there is a real (1.4%) risk of weakening or even losing the function of their left atrium.

More Study Needed on “In-hospital Deaths”

“In-hospital deaths” is a statistic that needs to be much more closely examined. The various studies often indicate that the deaths were not ‘procedure’ related. Then what was the cause of the deaths? People who have A-Fib also often have accompanying health problems. Unfortunately Medicare data doesn’t list cause of death.

Ablation Safer Than Drugs

We’re also indebted to Dr. Keane’s research for reviewing the non-randomized data to suggest that a life on antiarrhythmic meds (AADs) may be more risky and cause more complications that a catheter ablation (PVI), and we eagerly await the results of the ongoing CABANA trial in this regard. The success rate for AADs is low (52%) compared to a PVI. AADs also cause more adverse events than catheter ablation (30% vs 5%), and these adverse events are often more serious and permanent. AADs often don’t work or have intolerable side effects. If they do work, they often lose their effectiveness over time. We don’t yet have a magic pill that will cure A-Fib.

Because of the above problems with AADs, according to current guidelines you don’t have to first try various antiarrhythmic meds for a year or more before proceeding to a catheter ablation (though most doctors will still recommend you do so). By spending a year or more trying various AADs, you risk remodeling your heart, developing fibrosis which is irreversible, etc. Plus your quality of life deteriorates thanks to still being in A-Fib and/or dealing with the bad side effects of the AADs.

You Can Choose Ablation as First Line Choice

You can choose ablation as a first line choice. But you may have to be assertive with your doctor. According to current guidelines, you can choose to have an ablation as your first choice of treatment. Right now catheter ablation (and the more risky and traumatic surgical approaches) is the only therapy that offers a potential hope of a cure. (The editor has been cured for 16 years. Living in normal sinus rhythm is wonderful!)

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Last updated: Monday, April 27, 2020