Inefficacy and Proarrhythmic Effects of Flecainide and Encainide for Sustained Ventricular Tachycardia and Ventricular Fibrillation
- John M. Herre, MD;
- Christina Titus, RN;
- Michael Oeff, MD;
- Michael Eldar, MD;
- Michael R. Franz, MD;
- Jerry C. Griffin, MD; and
- Melvin M. Scheinman, MD
Abstract
Objective: To assess the efficacy of encainide and flecainide in treating patients with sustained ventricular arrhythmias.
Design: Patients were treated with encainide or flecainide. Efficacy was assessed by comparing the results of programmed ventricular stimulation while patients received therapy with the results while they were drug free.
Setting: The electrophysiology laboratory of the University of California at San Francisco.
Patients: Forty-nine patients with spontaneous or inducible sustained ventricular tachycardia or ventricular fibrillation for whom treatment with at least one class IA antiarrhythmic agent had failed.
Interventions: Patients were treated with encainide, 35 to 50 mg three or four times daily, or flecainide, 100 to 200 mg twice daily.
Results: Arrhythmia worsened early in 5 of 16 patients receiving encainide and 3 of 33 patients receiving flecainide. Patients with poor left ventricular function were more likely to exhibit proarrhythmia (P = 0.02). Nine of eleven patients receiving encainide and 23 of 28 patients receiving flecainide who had repeat programmed ventricular stimulation while receiving drug therapy still had inducible, poorly tolerated ventricular tachycardia.
Conclusion: Encainide and flecainide have a low efficacy rate and a high incidence of worsening of arrhythmia in patients with sustained ventricular arrhythmias, particularly when this condition is associated with poor left ventricular function.
Article and Author Information
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From the University of California at San Francisco, San Francisco, California. For current author addresses, see end of text.
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Requests for Reprints: John M. Herre, MD, Electrophysiology Laboratory, Sentara Norfolk General Hospital, 600 Gresham Drive, Norfolk, VA 23507.
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Current Author Addresses: Dr. Herre: Electrophysiology Laboratory, Sentara Norfolk General Hospital, 600 Gresham Drive, Norfolk, VA 23507.
Ms. Titus: Pacific Coast Clinical Coordinators, Inc., 643 Bair Island Rd., Suite 106, Redwood City, CA 94062.
Dr. Oeff: Klinikum Steglitz, Hindenburg Damm 30, 1 Berlin 45, Federal Republic of Germany.
Dr. Eldar: Neufeld Cardiac Research Institute, Sheba Medical Center, Tel Hashomer 52621, Israel.
Dr. Franz: Cardiology Division, Stanford University Medical Center, Stanford, CA 94305.
Drs. Griffin and Scheinman: Room 312, Moffitt Hospital, University of California, San Francisco, CA 94143-0214.
- © 1990 American College of Physicians
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