[Myocardial infarct in patients with normal coronary arteries]

Between November 1992 and April 1993, 864 coronary angiographies were performed at our institution. In 14 patients (1.6%), no significant coronary disease (> 50% stenosis) was found despite documented myocardial infarction. Of these, 2 patients (0.2%), aged 46 and 33 years, had perfectly smooth coronary arteries at angiography. The most commonly postulated mechanism of myocardial infarction in such patients is coronary spasm with superimposed thrombosis. The same risk factors as those operative in atherosclerotic coronary artery disease are thought to play a role in this setting. The prognosis is good. In one of the patients with < 50% stenosis of coronary vessels, a history of cocaine abuse could be elicited as the possible causal factor of acute myocardial infarction. Cocaine-induced coronary spasm can lead to arrhythmias, myocardial infarction or accelerated coronary atherosclerosis even in patients with normal coronary arteries. Myocarditis must be considered in the differential diagnosis of acute myocardial infarction in young patients with chest pain, typical electrocardiographic and enzymatic changes but without risk factors.