AF Symposium 2016

Predictors of Unsuccessful Ablations: It’s All About Remodeling

by Steve S. Ryan, PhD

If someone tells you to “Just live with A-Fib”, or “It’s no big deal,” or “A-Fib’s just a nuisance”, RUN, don’t walk, for a second opinion! Don’t wait—a long enough delay allows atrial remodeling to change your heart and makes it much more difficult to get a successful ablation (i.e. become A-Fib-free).

Predictors of Unsuccessful Persistent A-Fib Ablation

Dr Michele Haissaguerre, The Bordeaux Group

Dr. Michel Haissaguerre, in his presentation “Predictors of Clinical Outcomes in Ablation of Persistent AF Drivers”, found several predictors of unsuccessful ablation outcomes in persistent A-Fib cases. (Drum roll, please.) They are all related to atrial remodeling!

The predictors of unsuccessful outcomes are:

• A-Fib Duration (how long a patient had been in A-Fib prior to ablation)
• A-Fib Cycle Length (the faster the cycle length, the harder to achieve success)
• Number of Drivers (the more drivers mapped, the less chance of success)
• Arial Size (the more the left atrium is extended and stretched, the less chance of success)
• Fibrosis (being in A-Fib normally produces fibrosis)

Dr. Haissaguerre of Central Hospital, Bordeaux, France, used slides to explain his findings. (You may want to read this article together with Dr. Haissaguerre’s other presentation: Bordeaux New ECGI Ablation Protocol—Re-Mapping during Ablation.)

“Reentries” are Short Lived But Recur in the Same Region

Dr. Haissaguerre showed images of ECGI/ECVUE Cardio Insight mapping done either the day before the ablation or during the procedure. ECGI produces statistical density mapping of “reentries” (rotors) and focal breakthroughs. These reentries are short lived but periodically recur in the same region.

The Number of Driver Regions

The number of driver regions increases with how long a patient has been in persistent A-Fib. In cases of long-standing persistent A-Fib, he has found as many as 7 driver regions.

Fibrosis and Low Atrial Voltage

Dr. Haissaguerre cited the work of Dr. Marrouche which found decreased ablation success with the extent of fibrosis or atrial low voltage. (For more about Dr. Marrouche’s research, see: High Fibrosis at Greater Risk of Stroke and Precludes Catheter Ablation)

Characteristics of Reentries (Rotors)

Dr. Haissaguerre discovered several previously unknown characteristic of rotors:

• Driver domains are part of CFAE areas.
• Core trajectories or rotors are anchored at distinct parts of fibrosis.
• There is a strong link of A-Fib drivers to structural heterogeneities (dissimilar parts like the PVs and LAA opening).

For example, 98% of reentries are found at common points like the Left Pulmonary Vein/Left Atrial Appendage (LAA) area. Whereas focal discharges are mainly observed at the PVs (60% of patients), LAA, or Right Atrial Appendage (RAA).

A-Fib Termination Strongest Predictor of Ablation Success

After 12 months, 85% of patients with A-Fib termination were still free from A-Fib. In the small group of patients who did not achieve termination (and were electrically shocked to try to return them to sinus), 63% were A-Fib free after 12 months. The 37% who remained in A-Fib were all patients with persistent A-Fib.

Ablation Works Best if in Sinus Rhythm Before the Ablation

The A-Fib termination rate was 84% in patients in sinus rhythm at the time of the ablation (with an RF delivery time of only 22 minutes). To get persistent patients in sinus before the ablation, they often would be electrocardioverted.

Mapping of Atrial Tachycardias (ATs)

The ECGI system can also map ATs. Dr. Haissaguerre found that half the ATs found were focal ATs, “mostly localized reentry”. 68% were from driver regions previously ablated. 32% were from new sites.

The other half of the ATs were “Macroreentries” and required linear ablations to terminate.

How to Improve Ablation Outcomes

Dr. Haissaguerre stated that the key to improve ablation outcomes is to minimize atrial remodeling by:

1. Ablate earlier (after only a few months of persistent A-Fib, rather than letting patients go into long term persistent).
2. Restore patients to sinus rhythm before the ablation, especially in cases of longer lasting A-Fib.
3. Manage risk factors such as by using preventive drugs.

He showed slides of how flecainide reduced crucial driver regions, and how amiodarone both lengthened cycle length and decreased driver regions.

Dr. Haissaguerre’s Conclusions

• Noninvasive mapping visualizes AF drivers in a more specific way than other current approaches
• There’s a strong link of driver locations with structural heterogeneities (anatomical junctions and fibrosis)
• Predictors of clinical outcome—AF Duration, A-Fib Cycle Length, Number of Drivers, Atrial Size, Fibrosis―mainly relate to Atrial Remodeling with obvious practical implications

What Patients Need to Know

Don’t Live in A-Fib! The message for patients from Dr. Haissaguerre’s presentation is fairly obvious—Don’t settle for a life in A-Fib! A-Fib is a progressive disease that usually gets worse over time. It produces remodeling of the left atrium.

Danger of a Fibrotic Heart—Fibrosis: Most of the remodeling effects of living in A-Fib can be corrected or improved by a successful catheter ablation. But not fibrosis! (Which is generally considered permanent and irreversible).

Fibrosis produces collagen and scarring in the heart which is a permanent remodeling effect of A-Fib. Fibrotic tissue is scarred, immobile, basically dead tissue with reduced or no blood flow and no transport function. It results in a loss of atrial muscle mass. Over time it makes the heart stiff, less flexible and weak, overworks the heart, reduces pumping efficiency and leads to other heart problems. Read more about fibrosis in my article: A-Fib Produces Fibrosis—Experimental and Real-World Data.

Remodeling Makes Catheter Ablation More Difficult:  A successful ablation is much more difficult when your heart has been remodeled by A-Fib. Patients with Long-standing A-Fib develop as many as seven different driver regions, compared to only two in patients who were in Persistent A-Fib for only a couple of months. Even the ‘great’ Bordeaux group couldn’t cure all of these cases.

Ground-Breaking Discoveries Important for Patients

1―Ablation works best if you are in Sinus Rhythm BEFORE the ablation.
This principle is not yet generally understood and practiced by the EP community. As a patient you should seek out EPs who will try to get you back into sinus before your ablation.

Ask the EP you are interviewing, “Will you try to get me back into sinus rhythm before the ablation?” How will you do this?” They should answer that they will use Electrocardioversion and/or antiarrhythmic drugs to do this, particularly in cases of persistent A-Fib.

For example, one A-Fib patient emailed me that the Mayo Clinic Electrocardioverted her into sinus, then used Tikosyn to keep her in sinus for a month or two before her ablation.

2―A-Fib termination is the strongest predictor of ablation success.
This discovery is very important for patients. Some previous research said that it really didn’t matter if A-Fib terminated during the ablation.

Nevertheless, in Dr. Haissaguerre’s research, 84% of patients with A-Fib termination during the ablation procedure were still free of A-Fib after 12 months.

The Bottom line for Patients

A-Fib termination during the ablation procedure should be the goal of every EP. You should seek out EPs who will make that extra effort (such as replacing the CryoBalloon catheter with a RF catheter to isolate non-PV triggers). All too many EPs aren’t willing or aren’t able to do that.¹

Dr. Michel Haïssaguerre

 Dr. (Prof.) Michel Haïssaguerre, Central Hospital, Bordeaux, France, and his colleagues invented pulmonary vein catheter ablation for A-Fib (PVA/I). The Bordeaux Group is considered one of the top A-Fib centers in the world and noted for their cutting edge research in the treatment of Atrial Fibrillation. Interesting fact: I (Steve Ryan) was their first US patient in 1998.

Return to 2016 AF Symposium Reports by Steve Ryan, PhD

If you find any errors on this page, email us. Y Last updated: Saturday, February 16, 2019

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