Possible proarrhythmic effects of tocainide in dilated cardiomyopathy.

A patient with a dilated cardiomyopathy experienced a cardiac arrest when taking tocainide for asymptomatic nonsustained ventricular tachycardia. After successful resuscitation from ventricular fibrillation and exclusion of a myocardial infarction, an electrophysiological evaluation was performed. Drug-free study #1 revealed no induction of ventricular tachycardia. A tocainide study revealed induction of sustained monomorphic ventricular tachycardia. Drug-free study #2 revealed induction of nonsustained ventricular tachycardia. This report illustrates a possible proarrhythmic effect of tocainide.