BORDEAUX, FRANCE. Although the success of antiarrhythmic drugs in the treatment of atrial fibrillation (AF) leaves a lot to be desired, it is generally accepted that therapy with 2 or more antiarrhythmics should be tried before catheter ablation is considered. A group of electrophysiologist from Australia, Canada, France and the United States now question the wisdom of continuing to try additional, different antiarrhythmics in patients who have already failed at least one such drug.
Their clinical trial involved 112 patients with paroxysmal AF (average age of 51 years, 16% women). Most (74%) had lone AF with an average (median) of 12 episodes per month lasting an average of 5.5 hours each (median). After a through medical evaluation at enrolment, the study participants were randomized into a catheter ablation (CA) group and an antiarrhythmic drug (AAD) group. Patients in the CA group underwent a standard PVI with right atrial flutter ablation and additional lesion lines as required. Up to two additional ablations were allowed within the 3 months following the initial procedure. The overall repeat rate was 80% and the rate of major complications was 1.9% (tamponade and stenosis).
Patients in the AAD group were allowed to try up to 3 different drugs during the 3 months following enrolment and were then left on the last drug tried for the remaining 9 months of the 1-year study period unless they elected to undergo an ablation after the first 3 months of trying unsuccessful antiarrhythmics (63% did so after about 6 months). Prior to enrolment, flecainide and beta-blockers were the most commonly used drugs followed by sotalol and propafenone. During the study, amiodarone was tried for the first time by 18 patients in the AAD group and failed in 12 (66%) of these patients.
All patients were monitored with 12-lead ECGs and 24-hour Holter recordings at 3, 6 and 12 months following enrolment. Any afib episode lasting longer than 3 minutes, whether picked up during monitoring or reported by the patients, was considered a treatment failure. At the end of the study (12 months after enrolment), 89% of the participants of the CA group were afib-free without the use of antiarrhythmics. In contrast, only 23% of those in the AAD group were free of afib at the end of the study and they, of course, were still taking antiarrhythmic drugs on a daily basis. The researchers observed that afibbers with a higher left ventricular ejection fraction at enrolment were more likely to have a successful ablation than were those with a lower ejection fraction (65% vs. 56%). An evaluation of exercise capacity and quality of life at the 12-month mark showed significantly greater improvement in the CA group than in the AAD group.
The authors conclude that CA is superior to further AAD treatment in patients who have previously taken and failed antiarrhythmics. NOTE: Nine of the 14 EPs reporting on the trial have financial ties to ablation catheter manufacturers.
Jais, P, et al. Catheter ablation versus antiarrhythmic drugs for atrial fibrillation. Circulation, Vol. 118, December 9, 2008, pp. 2498-2505
Callans, DJ. Apples and oranges: comparing antiarrhythmic drugs and catheter ablation for treatment of atrial fibrillation. Circulation, Vol. 118, December 9, 2008, pp. 2488-90
Editor's comment: Our LAF surveys have found generally poor efficacy of antiarrhythmic drug therapy. This study certainly confirms those findings. The seemingly inescapable conclusion is that if antiarrhythmics do not work after the first or, at the most, the second try, get in line for an ablation. An exception to this is if the drug prescribed was a beta-blocker. Beta-blockers do not prevent afib episodes they merely reduce the heart rate during an episode. Furthermore, vagal afibbers prescribed beta-blockers can expect their condition to worsen and may well succeed in eliminating their episodes altogether by discontinuing these drugs.