In young patients with unexplained ventricular fibrillation, coronary occlusion may be missed by echocardiogram and misinterpreted by CT. We report two patients presenting with ventricular fibrillation and initially negative workup, later identified to have occlusion of left main coronary artery. We demonstrate the importance of angiography to rule out coronary occlusion in patients with unexplained ventricular fibrillation.