Idiopathic ventricular fibrillation.

A review of the literature dealing with sudden death revealed 19 articles in which ostensibly healthy patients with documented VF unrelated to any known cardiac or noncardiac etiology are reported. Fifty-four patients fulfilling the criteria for idiopathic VF, including 14 patients investigated at our institution, are described. The mean age of patients for studies that reported age data was 36 years, with a male-to-female ratio of 2.5 to 1. Over 90% of the patients required resuscitation, while syncope due to nonsustained VF occurred in the rest. Diagnosis of VF was preceded by syncope in one fourth of the patients. Holter monitoring and exercise stress tests were often unrewarding. Available electrophysiologic data revealed a 69% inducibility rate of sustained ventricular tachyarrhythmias using nonaggressive protocols of ventricular stimulation in most cases. Induced tachyarrhythmias were poorly tolerated, and were mostly of polymorphic configuration. Class IA antiarrhythmic agents were highly effective in preventing reinduction of these arrhythmias. Available figures suggest an 11% rate of sudden death within 1 year of diagnosis. Appropriate antiarrhythmic therapy appears to improve prognosis. Reviewed data suggest that idiopathic VF represents an underestimated cause of sudden cardiac death in ostensibly healthy patients. An international registry of patients with idiopathic VF is warranted.