Determinants of antiarrhythmic drug efficacy for ventricular tachyarrhythmias using ambulatory monitoring and electrophysiological techniques.

Sustained ventricular tachycardia and ventricular fibrillation are life-threatening arrhythmias with high rates of recurrence.1'2 Empiric antiarrhythmic drug therapy has a low success rate for preventing recurrences of these arrhythmias.3 Therefore, the choice of drug therapy has centered around two methodologies to predict drug efficacy: programmed ventricular stimulation with serial drug testing and suppression of ambient complex ventricular ectopy and nonsustained ventricular tachycardia detected by ambulatory monitoring recording and exercise stress testing. There is evidence that both approaches can successfully identify appropriate prophylactic antiarrhythmic drug therapy for sustained ventricular tachyarrhythmias.3-6 The study reported in this issue of Circulation7 was designed to compare the effectiveness of these two methodologies in determining antiarrhythmic drug treatment for such arrhythmias and to identify any clinical characteristic that can help predict drug efficacy in the context of these different methodologies.