Atrial Fibrillation Ablation and Congestive Heart Failure: Where Are We Going?
Disclosure: Consultant and research grants from Biosense Webster, Atricure, Cryocath and Ablation Frontiers.
Pub Date: Monday, February 2, 2009
Author: Kenneth Ellenbogen, MD, FAHA
Khan MN, Jais P, Cummings J, Di Biase L, Sanders P, Martin DO, Kautzner J, Hao S, Themistoclakis S, Fanelli R, Potenza D, Massaro R, Wazni O, Schweikert R, Saliba W, Wang P, Al-Ahmad A, Beheiry S, Santarelli P, Starling RC, Dello Russo A, Pelargonio G, Brachmann J, Schibgilla V, Bonso A, Casella M, Raviele A, Haissaguerre M, Natale A., Pulmonary-vein isolation for atrial fibrillation in patients with heart failure., The New England journal of medicine, 359 (17) 1778-85. View in PubMed
The results of prior multicenter trials comparing a rate-control strategy to a rhythm-control strategy in atrial fibrillation showed no advantage of maintaining sinus rhythm with antiarrhythmic drugs, such as amiodarone, compared to heart-rate control. This hypothesis was tested in patients with congestive heart failure, and the results of this study also showed no reduction in death from cardiac causes, comparing the strategy of heart-rhythm control to a rate-control strategy.
Given the disappointing results of antiarrhythmic drug therapy in maintaining sinus rhythm and demonstrating a cardiovascular mortality benefit in clinical trials, it seems only natural that newer techniques for the treatment of atrial fibrillation should be tested in this population. The present study included a group of 81 symptomatic patients with New York Heart Association Class II or III heart failure, an ejection fraction less than 40% while taking medical therapy, and drug-resistant atrial fibrillation. The patients were randomized to undergo either pulmonary vein isolation or atrioventricular (AV) node ablation with biventricular pacing. The composite primary end point was quality of life, measured with the Minnesota Living with Heart Failure questionnaire, distance walked in the 6-minute walk test, and ejection fraction measured by echocardiography. The main results showed a greater improvement in quality of life, a longer 6-minute walk test (by a mean of 43 meters), and a higher mean increase in ejection fraction by 7% in the patients undergoing radiofrequency catheter ablation of the pulmonary veins. Episodes of recurrent atrial fibrillation were recorded by an event monitor, and routine transmission was performed 2 to 3 times per week, even if asymptomatic. In the group of patients randomized to undergo catheter ablation, sinus rhythm was maintained in 71% of patients not receiving antiarrhythmic drugs. A higher incidence of progression of atrial fibrillation was found in the patients who underwent AV node ablation and pacing.
What do these findings mean for the large population of patients with heart failure and atrial fibrillation? First, this is a small study and the results from this study should not be widely generalized to the management of atrial fibrillation in patients with heart failure. Secondly, pulmonary vein ablation was performed by extremely experienced ablationists, and these results cannot be generalized to less experienced interventional electrophysiologists. Third, follow-up was performed at 6 months, which is a short time frame and the question of whether these results can be maintained during long-term follow-up is unknown. The degree of left atrial dilation in patients in this clinical trail was relatively mild and the risks of performing ablation in sicker patients with congestive heart failure is unknown.
This important study highlights the need for future large scale studies of atrial fibrillation ablation and the potential benefit of this procedure to decrease cardiovascular morbidity and mortality as well as improve long-term cardiac function. The future of atrial fibrillation ablation will require many more well-designed clinical trials, but the present trial does show that excellent results of catheter ablation of atrial fibrillation are achievable, with excellent technical abilities of the right operators in the right patients. Future studies will better define those patient subgroups and the risks and benefits of these procedures.
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- Hsu L-F, Jais P, Sanders P, et al. Catheter ablation for atrial fibrillation in congestive heart failure. N Engl J Med 2004;351:2373-2383.
- Wood MA, Brown-Mahoney C, Kay GN, Ellenbogen KA. Clinical outcomes after ablation and pacing therapy for atrial fibrillation: a meta-analysis. Circulation 2000;101:1138-1144.
-- The opinions expressed in this commentary are not necessarily those of the editors or of the American Heart Association