Data concerning the natural history of asymptomatic coronary artery disease (CAD) has been limited to epidemiologic rather than angiographic studies, thus leading to uncertainty as to whether warning symptoms and signs will identify subjects with silent myocardial ischemia before morbid events. To address this issue, 50 apparently healthy men with angiographically proven CAD and asymptomatic exercise-induced ST depression have been followed prospectively for 15 years in the Oslo Ischemia Study. Fourteen men died. The initial presenting clinical event in these 14 men was chest pain in 4 (30%)--but in only 1 case was it recognized as typical angina--silent myocardial infarction in 5 (35%) and sudden death in 5 (35%). Thirty-six men survived, with 19 developing symptoms. Overall, chest pain was the first clinical event in 22 of the total of 33 men with symptoms (66%), whereas myocardial infarction occurred in 6 (18%) and sudden death in 5 (16%). Although chest pain occurred in 22 men, it was clinically diagnosed as typical angina pectoris in only 6. These observations suggest that there is an absence of clear-cut ischemic symptoms in many asymptomatic patients before morbid events.