Persistent left superior vena cava in a man with ventricular fibrillation.

A patient who had recurrent syncope and an episode of sudden cardiac arrest due to ventricular fibrillation unassociated with acute myocardial infarction is presented. An isolated left superior vena cava was discovered during electrophysiologic study. Ventricular fibrillation was readily induced by programmed ventricular stimulation in the initial (off the drugs) and subsequent serial electropharmacologic testings. These findings suggest that ventricular fibrillation may be the cause of sudden death in patients with this congenital abnormality.