Exertional cardiac arrest may result from ventricular standstill due to asystole or ventricular fibrillation; the literature records an instance of the former in a patient with both aortic stenosis and coronary heart disease. Without this valvular lesion, patients with marked coronary heart disease are more likely to experience ventricular fibrillation. Seven cases of sudden, unexpected syncope and cardiac arrest are cited, two during exercise testing and five during exercise training. All required and promptly responded to a single shock of a defibrillator, and only one showed evidence of possible myocardial infarction. Important implications of these observations are discussed.