Assessment of Atrioventricular Junction Ablation and VVIR Pacemaker Versus Pharmacological Treatment in Patients With Heart Failure and Chronic Atrial Fibrillation
To the Editor:
We congratulate Brignole et al1 on their study. In particular, we found ourselves in agreement with their emphasis on the requirement for a (randomized) controlled trial in this field, a void which they have sought to fill. We are somewhat puzzled by their choice of control, however, and fear that it points to a gulf between the electrophysiology community and the heart failure community.
Whilst it appears that the electrophysiologist’s reaction to the copresentation of atrial fibrillation and congestive heart failure is to reach for his ablation catheter, our reaction to the copresentation of atrial fibrillation and congestive heart failure is to book an anaesthetist and reach for the defibrillator. We were surprised that nowhere did Brignole et al even mention the word “cardioversion,” and neither did Dr Scheinman in his editorial,2 despite the fact that he drew attention to the remarkable results that can be achieved with restoration of sinus rhythm.3 It may be that cardioversion had been attempted in a number of patients (some might not even accept the diagnosis of “chronic” atrial fibrillation until electrical cardioversion has been tried and has failed), but nowhere is this information supplied. The mean duration of arrhythmia was fairly long but was exceeded by its standard deviation, so both groups must have included patients who had had atrial fibrillation for a relatively short time. We are not even told whether all the patients were still in atrial fibrillation at the end of the trial.
We are not aware of a randomized controlled trial comparing the results of electrical cardioversion and medical therapy in patients with atrial fibrillation and congestive heart failure. The safety and efficacy of electrical cardioversion are so well founded that we would consider it unethical to conduct such a trial. The safety and efficacy of ablation and pacemaker insertion are not so well founded, however, and it would appear to us that the ideal comparison would be between ablation and cardioversion, not between ablation and medication. To have randomized half their patients to medication alone under these circumstances seems to us questionable.
- Copyright © 1999 by American Heart Association
Brignole M, Menozzi C, Gianfranchi L, Musso G, Mureddu R, Bottoni N, Lolli G. Assessment of atrioventricular junction ablation and VVIR pacemaker versus pharmacological treatment in patients with heart failure and chronic atrial fibrillation: a randomized, controlled study. Circulation. 1998;98:953–960.
Scheinman MM. Atrial fibrillation and congestive heart failure: the intersection of two common diseases. Circulation. 1998;98:941–942.
We believe the electrophysiologist’s reaction to the copresentation of atrial fibrillation and congestive heart failure is the same as that of the specialist in heart failure: namely, to make every effort to restore and maintain sinus rhythm for as long as possible. However, at least 12% of paroxysmal atrial fibrillation is considered intractable despite multiple-drug therapy and repeated cardioversions.R1 Moreover, in epidemiological studies, about 60% of patients with atrial fibrillation have a chronic form. In most cases, the main problem is not converting to sinus rhythm but maintaining it for a long time and avoiding the adverse effects of therapies necessary to obtain that goal. Thus, current treatments often fail to maintain stable sinus rhythm. That was the case with our patients who underwent AV junction ablation only when reasonable attempts to restore stable sinus rhythm (including repeated cardioversions) had failed. The median duration of chronic atrial fibrillation of the enrolled patients in our study was 2.5 years, and before the development of the chronic form, most patients had had a history of paroxysmal tachyarrhythmias lasting 9±6 years (median, 7 years). Admittedly, some patients were enrolled a relatively short time after the development of chronic atrial fibrillation (minimum of 6 months) when it seemed clear that sinus rhythm could not be maintained due to frequent relapses, adverse effects of antiarrhythmic drugs, and/or severity of heart failure that required a prompt intervention. All of the patients remained in atrial fibrillation throughout the study.
We know from epidemiological studiesR2 that atrial fibrillation is associated with morbidity and mortality, and we have reason to hope that outcomes will improve if we can achieve permanent sinus or atrial paced rhythm. Nevertheless, epidemiological studies are unable to show whether a strategy aimed at preventing atrial fibrillation and maintaining sinus rhythm is better than another that allows control of the ventricular rate. New nonpharmacological therapies (which encompass surgical or catheter ablation procedures, implantable atrial defibrillator, and preventive pacemakers) are under investigation and may be able to maintain sinus or atrial paced rhythm when conventional treatments have failed. Placebo-controlled trials with warfarin have shown a substantial reduction in stroke rates, but we do not yet know enough about the risk-benefit ratio of these new therapies, which can only be determined from controlled clinical trials after they have shown promise in mechanistic and pilot studies. The benefits of sinus rhythm to reduce stroke, heart failure, hospitalization, and death and to improve symptoms, exercise capacity, and functional status should be quantified by controlled clinical trials. We hope that the National Heart, Lung, and Blood Institute will take responsibility for conducting and monitoring that trial.R3 We conclude that the best strategies for management of atrial fibrillation have yet to be defined.