In a prospective study we identified a group of 12 patients diagnosed as having acute myocardial infarction but with electrocardiographic features of non-transmural infarction and serological evidence of recent Coxsackie B infection favouring the possibility of myocarditis. The group included 9 females and 3 males, aged from 38-60 y. Coronary arteriography was carried out in 11 patients. Eight of the 11 patients showed no significant (greater than or equal to 50%) coronary arterial obstruction. We suggest that coronary artery disease did not contribute to the clinical presentation in the majority of these patients and that the likely diagnosis was viral myocarditis in at least 6 of them. We conclude that viral myocarditis may simulate myocardial infarction and contribute to the uncommon but controversial syndrome of myocardial infarction with a normal coronary arteriogram.