2013 BOSTON ATRIAL FIBRILLATION SYMPOSIUM
Dr. Jais began his presentation by establishing a scientific basis in the published literature for Reverse Remodeling.
When dogs were paced into Chronic A-Fib for eight weeks, then put back into Sinus Rhythm for 7 to 14 days, complete electrical remodeling occurred rapidly; i.e., their hearts’ electrical system functioned normally. Also there were reduced Premature Atrial Contractions (PACs). But “gross and ultrastructural anatomic changes persisted.” Once the dogs’ hearts were structurally damaged by things like fibrosis, they didn’t improve by being in Sinus Rhythm. Also, they were more vulnerable to going back into A-Fib, probably due to the permanent structural abnormalities they developed from having been in Chronic A-Fib. The point that Dr. Jais established was that electrical remodeling does rapidly work in A-Fib, but not necessarily structural remodeling. And this holds true for Reverse Remodeling as well. Remodeling is a pathological process, but treatments can reverse that process. 1
In a study of goats induced into Chronic A-Fib, Dr. Allessie studied microscopic cellular changes. After four months of being back in Sinus Rhythm , there was some structural remodeling such as a reduction in left atrial diameter, “Atrial myocyte diameter and Myocytes with severe Myolisis & connexin 40 normalized.” But “Extracellular matrix fraction per myocyte remained increased (fibrosis-like structural change didn’t improve).” However, electrical remodeling almost completely reverted when the goats were put back in Sinus Rhythm. 2
In a study by Dr. Nattel of reversal of heart failure in dogs, fibrosis and “local conduction abnormalities” didn’t improve. Even after five weeks in sinus, the substantial increase in fibrosis persisted. 3
In a Japanese study in 2010, 51 people with Persistent A-Fib for more than a year received a combination of Class I & III antiarrhythmic drugs (no electrocardioversion) before ablation. 33 did revert to sinus, 18 didn’t. The only significant difference between these two groups was the prior duration of their A-Fib. The group that did revert had been in persistent A-Fib for an average of 24 months, the group that didn’t revert for an average of 52 months. For the group that did revert to sinus, the ablation procedure was shorter and easier, a lower number of cardioversions were needed during the ablation procedure, and the patients in the sinus group did much better long term than the group that wasn’t reverted to sinus.4
In 2011 Dr. Steinberg published perhaps the first study in humans of what Dr. Jais calls “Reverse Remodeling. “ 71 Persistent A-Fib patients were pretreated by Electrocardioversion (DC shock) and dofetilide for 3 months prior to having a PVI. P wave duration was shortened when persistent A-Fib patients were returned to Sinus Rhythm, and good ablation results were obtained in these patients. But some patients didn’t respond at all. 5
Dr. Jais’ Research
In a 2012 study by the Bordeaux group and two other centers, 40 persistent A-Fib patients were cardioverted at least 1 month prior to ablation. Another 40 patients matched for age, sex and A-Fib duration were not cardioverted and were in A-Fib at the time of their ablation (control group). Both groups were also taking amiodarone or dronedarone.
(The Bordeaux Group uses a five-step protocol for ablating persistent A-Fib. See http://a-fib.com/research-and-innovations-in-atrial-fibrillation/significant-research-and-scientific-studies/bordeaux-five-step-ablation-protocol-for-chronic-a-fib)
After being at least one month in Sinus Rhythm, the sinus group required 50 minutes less procedure time, their ejection fraction was significantly improved , their A-Fib cycle length was longer, their results were better—95% terminated A-Fib versus 77% in the control group, 82% converted directly to Sinus Rhythm versus only 12% in the control group, when ablating CFAEs it was only necessary to ablate 40% of CFAEs versus double that for the control group, there were 40% lower number of RF lesions needed in the sinus group versus much more in the control group.
In the persistent patients in whom they were able to use ECGI, non-PVI triggers were significantly reduced. The ECGI movies of each group were very different “like night and day.” The control group seemed to have very mixed up and clashing rotors, focal sources, etc.
In terms of overall success rate including re-dos after one year, the sinus group had an 80% success rate, while the control group had a similar 70% success rate. (This small difference can be explained by the effectiveness of the Bordeaux group’s five-step protocol which worked equally well on difficult persistent A-Fib cases, even if they weren’t in sinus before the ablation.)6
What it All Means
“Reverse Remodeling” is a major medical breakthrough for A-Fib patients in persistent A-Fib. It makes ablations shorter, easier, more effective, etc. But more importantly it significantly reduces RF lesions and damage to our hearts. A 40% reduction in burns, permanent scarring, dead fibrotic tissue, etc. is welcome news for persistent A-Fib patients. I talked with doctors at the Symposium who already are using Reverse Remodeling on their patients with good results. Reverse Remodeling is so simple to do, so effective and better for patients, that most A-Fib centers in the very near future will be using Reverse Remodeling.
Dr. Jais, in an email to the author, added, “both experimental and human data strongly advocate early ablation in persistent A-Fib, while there is no emergency in paroxysmal A-Fib. Several ongoing studies should demonstrate that in the future.” He also wrote, “I do believe we will also see studies demonstrating the benefit of A-Fib ablation on morbidity and mortality.”
Last updated: Tuesday, March 18, 2014
- Everett, T.H. et al. “Electrical, Morphological, and Ultrastructural Remodeling and Reverse Remodeling in a Canine Model of Chronic Atrial Fibrillation.” Circulation. 2000:102:1454-1460.↵
- Citation: Ausma, J et al. “Reverse Structural and Gap-Junctional Remodeling After Prolonged Atrial Fibrillation in the Goat.” Circulation. 2003; 107: 2051.↵
- Shinagawam K. et al. “Dynamic Nature of Atrial Fibrillation Substrate During Development and Reversal of Heart Failure in Dogs.” Circulation. 2002;105:2672-2678.↵
- Igarashi, M. et al. “Effect of Restoration of Sinus Rhythm by Extensive Antiarrhythmic Drugs in Predicting Results of Catheter Ablation of Persistent Atrial Fibrillation.” AJC. 2010; 106: 62↵
- Khan, A. et al. “Pulmonary Vein Isolation Alone in Patients with Persistent Atrial Fibrillation: An Ablation Strategy Facilitated by Antiarrhythmic Drug Induced Reverse Remodeling.” JCE. 2011;22: 142.↵
- Rivard, L. et al. “Improved outcome following restoration of sinus rhythm prior to catheter ablation of persistent atrial fibrillation: A comparative multicenter study.” Heart Rhythm. 2012; 9: 1025.↵