It has been recognized for many years that myocardial infarction is almost invariably associated with significant narrowing of one or more coronary arteries. However, the widespread use of selective coronary angiography has resulted in an increasing number of reports of patients with proved infarction and patent coronary arteries. The purpose of this study was to analyze whether any clinical features distinguishes patients with these findings from those having coronary arterial lesions.

The clinical association of myocardial infarction with no significant stenosis of major coronary artery on cineangiogram was analysed retrospectively. The findings on the 13 patients in this group was compared with those of myocardial infartion with significant coronary artery stenosis.

There were no significant differences in risk factors, hemodynamic findings of cardiac catheterization and the site of infarction between both groups. However, the patients with no significant stenosis of coronary artery had fewer complications during hospitalization and lesser ST segment change during exercise test before discharge.

It could be concluded that the acute myocardial infarction with no significant stenosis of coronary arteries would have the better prognosis. The mechanism of the acute myocardial infarction with no significant stenosis of coronary arteries might be studied in the aspect of the coronary artery spasm and the alternation of function of endothelial cell.