During a routine physical examination, a 34-year-old man, in apparent good health, had an electrocardiogram which revealed left axis deviation. Cardiac evaluation disclosed mild aortic regurgitation and left anterior fascicular block. Nine months later, the patient was admitted to the critical care unit after he had experienced cardiac arrest while jogging. Angiograms demonstrated a large unruptured aneurysm in the right coronary sinus of Valsalva protuding into the left ventricle. Echocardiographic manifestations also suggested also suggested a sinus of Valsalva aneurysm. The defect was repaired through an aortic approach. The aneurysmal sac was emptied and the neck sutured securely. Twenty-two months postoperatively, the patient continues to be asymptomatic. We anticipate that this will decrease the threat of recurrent arrhythmias..