Prodromal symptoms and cardiac history were examined in 227 patients with coronary artery disease who were successfully resuscitated after out-of-hospital cardiac arrest. Cardiac arrest was sudden--with either no symptoms or symptoms for less than 1 hour--in 71% of the patients. Nonsudden death--death occurring after more than 1 hour of symptoms--occurred in 29% of the patients. A history of cardiovascular disease was present in 85% of patients with sudden cardiac arrest and in 83% with nonsudden arrest. Cardiac arrest occurred without symptoms in 38% of the patients with sudden cardiac arrest and was the first expression of coronary artery disease in 4% of the entire study group. This study indicates that cardiac arrest usually occurs with symptoms and almost always in the setting of a history of cardiovascular disease.