Ventricular tachycardia-flutter associated with disopyramide therapy: a report of three cases.

Three patients developed episodes of ventricular tachycardia and/or flutter-fibrillation while receiving disopyramide (Norpace). Syncope was the presenting complaint in all of them. The arrhythmias did not recur after disopyramide was discontinued. The Q-T interval was markedly prolonged in all three patients. One patient developed syncope associated with both quinidine and Norpace therapy. It is postulated that disopyramide, like quinidine, may provoke ventricular flutter-fibrillation in sensitive patients by similar mechanisms.