Single coronary artery, ventricular tachycardia, and a family history of sudden death.

A single coronary artery was found in a 55-year-old woman undergoing coronary angiography. The left coronary had a normal distribution, with the right coronary originating as a continuation of the distal left circumflex (L-I subtype). The patient had a 5-month history of chest pains of short duration accompanied by a feeling of tachycardia. During childhood, the patient experienced frequent episodes of syncope. The patient's brother died suddenly of an unknown cause, presumably cardiac, at the age of 42. Because of an episode of nonsustained ventricular tachycardia during an ergometer exercise test, the patient underwent a comprehensive program of diagnostic procedures but no other abnormalities were demonstrated. A cardioverter defibrillator was implanted.