Sudden cardiac death caused by coronary ostial compression by an aneurysm of the sinus of Valsalva.

A 22-year-old man was asymptomatic until he died suddenly after being startled. Post-mortem examination was normal except for aneurysmal dilatation of the left Sinus of Valsalva, the upper margin of which formed a flap-like ridge, partially occluding the ostium of the left main coronary artery which arose immediately above it. Further compression of this "slit-like" orifice by aneurysmal distention was the proposed cause of myocardial ischaemia and arrhythmic death.