Copyright © 2004 by the European Society of Cardiology.
Response to the Letter to the Editor
Prevention of atrial fibrillation after cardioversion: results of the PAFAC trial
Professor of Medicine, Cardiology, Medizinische Klinik und Poliklinik C, Universitätsklinikum Münster, Albert-Schweitzer-Straße 33, D-48149 Münster, Germany
* Tel.: +49 251 834 7617; Fax: +49 251 834 7864 (E-mail: g.breithardt{at}uni-muenster.de).
To the editor,
We share the concerns of Dr. Shelton concerning the safety of antiarrhythmic drug therapy. The intention of this trial, planned some years ago, was indeed to assess the efficacy and safety of antiarrhythmic drugs in maintaining sinus rhythm after electrical cardioversion. Therefore, we did not discuss the important and presently much debated issue of which strategy to prefer — rate control or rhythm control.
We agree that amiodarone and dofetilide are now the only drugs for which studies have demonstrated a neutral effect on survival in heart failure. However, our population was not a heart failure population. His statement that 42% had NYHA class II or above heart failure symptoms is correct but misleading since only 4% had NYHA III and none IV. Putting it differently, 50% of patients were in class I or II whereas 38% did not report any heart failure symptoms. Furthermore, the question regarding exercise capacity could only be posed to the patients at the time when they were in atrial fibrillation, as only patients with persistent atrial fibrillation were included.
Indeed, 21% of patients had angina pectoris but only 7% of all patients had confirmation of coronary artery disease by angiography and only a minority (5%) had prior myocardial infarction. Angina pectoris in atrial fibrillation is a quite non-specific symptom which is mostly not related to the presence of obstructive coronary artery disease, except for those patients who report typical angina pectoris outside episodes of atrial fibrillation.
Thus, our population is in no way comparable to, e.g., the CAST population on which the conclusion not to use class I drugs was based.1 We used sotalol as one of our drugs due to its frequent use in many countries. Data from SWORD using d-sotalol did not seem to be relevant for our study since we used dl-sotalol with its β-blocking effect and effect on cardiac repolarization. Indeed, recent data show that the mode of action of sotalol in atrial fibrillation may be more due to the β-blocking effect than the class III effect.2
We agree that present data show that amiodarone is superior to sotalol and class I antiarrhythmic drugs as shown by CTAF.3 These data were not available when we started our trial. In addition, there is great concern for long-term tolerability of amidarone especially with regard to thyroid function in countries with a high prevalence of subclinical thyroid disease.
His mentioning the very recent growing evidence for the prevention of occurrence and recurrence of atrial fibrillation in patients with systolic dysfunction by using ACE-inhibitors, angiotensin-receptor blockers and chronic β-blockade points to the importance of other mechanisms of drug action than merely antiarrhythmic ones.
We concur that if antiarrhythmic drugs are used for maintenance of sinus rhythm, their safety profile is of utmost concern. This was actually the background for setting up our trial which is the first large randomised double-blind trial which addresses the issue of safety with regard to serious adverse events but for funding reasons could not be large enough to have all-cause mortality as the primary endpoint.
References
- Akhtar M, Breithardt G, Camm AJ, et al. CAST and beyond. Implications of the Cardiac Arrhythmia Suppression Trial. Task Force of the Working Group on Arrhythmias of the European Society of Cardiology Circulation 1990;81:1123-1127.
[Free Full Text] - Plewan A, Lehmann G, Ndrepepa G, et al. Maintenance of sinus rhythm after electrical cardioversion of persistent atrial fibrillation; sotalol vs bisoprolol Eur Heart J 2001;22:1504-1510.
[Abstract/Free Full Text] - Roy D, Talajic M, Dorian P, et al. For the Canadian Trial of Atrial Fibrillation Investigators. Amiodarone to prevent recurrence of atrial fibrillation New Engl J Med 2000;342:913-920.
[Abstract/Free Full Text]
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