Background: Acute myocardial infarction (MI) in patients with normal coronary arteries has been recognized for several years. In most cases its etiology is unknown. The objective of the present study was to describe clinical features and medium term follow-up of those patients.
Patients and methods: Between April 1991 and December 1996, 9860 coronary angiographies were performed in our hospital. During this period 17 patients with documented myocardial infarction and completely normal coronary arteries were identified. Acute myocardial infarction was defined as the clinical event with acute angina pectoris, ST-elevation typical for myocardial infarction, and an increase in serum creatinine phosphokinase (CPK) above 125 U/l.
Results: The mean peak CPK was 675 U/l (range: 129-1760 U/l). All 17 patients revealed significant ST-segment elevation. According to the ECG criteria there was no predilection for a specific location of MI (9 anterior MIs and 8 inferior MIs). Thrombolytic therapy was performed in 9 patients. In 12 patients areas of localized hypo- or akinesia were shown on left ventricular cineangiography. The mean ejection fraction was 61.5+/-10.3%. The age and sex distribution revealed a bimodel character: there was a younger age group of 9 patients, all men with a mean age of 35.9 years (31-43) and all strong cigarette smokers (mean 28 cigarettes/day) and there was an older group of 7 patients (1 man, 6 women) with a mean age of 56,4 years (47-68) and no significant association with cigarette smoking. During a mean follow-up period of 48.6 months (31-85 months) no patient died and no patient suffered from recurrent chest pain and used nitroglycerin occasionally.
Conclusion: Patients with acute MI and angiographically normal coronary arteries show a bimodal sex and age distribution: a younger age group, all men and uniformly strong cigarette smokers and an older group predominantly women with no significant association with cigarette smoking. Both groups seem to have a favorable prognosis.