The following report concerns 6 cases (4% of a series of 142 consecutively studied patients with myocardial infarction) of myocardial infarction proved on clinical grounds with normal or near normal coronary arteries at coronary angiography obtained several months later.

The clinical data was shown in Table 1 and Table 2. All 6 patients were male.

Three were in the fifth, two in the sixth, and one in the seventh decade. Multiple risk factors were present in only one patient. Areas of localized dyskinesia or hypokinesia were demonstrated in five on the left ventricular cineangiography. The left ventricular end-diastolic pressure was greater than 12 mmHg in all 6 patients. One patient had hypertrophic cardiomyopathy and the remaining 5 patients had no underlying heart diseases. One patient had moderate congestive heart tailure. It is possible that prolonged, localized coronary artery spasm or platelet thrombi that subsequently resolved are a part of the pathogenic mechanism.