Myocardial infarction in young adults under 30 years: risk factors and clinical course.

The clinical features and course of 30 patients (26 men and 4 women) under 30 years of age (mean age 27.3 years) with an acute myocardial infarction (MI) are described. The most common risk factor among this group of patients was smoking in 20 patients (66%). The prevalence of the other risk factors was low: hyperlipidemia in four patients and family history of ischemic disease in another four patients, diabetes mellitus, hypertension, and obesity each in one patient. Seven patients (23%) had none of the conventional risk factors. Three patients were exerting themselves prior to the onset of their MI pain; all of them had normal coronaries. Five patients experienced chest pain prior to MI, among them only two experienced classical angina pectoris. Eighteen patients underwent uncomplicated MI. The complications in the other 12 during the acute MI were rhythm disturbances in eight and congestive heart failure in four. Cardiac catheterization was performed in 25 patients. The occurrence of zero, one, or multivessel disease was equal. The 30 patients were followed up from six months to 15 years (mean 7 years). In 18 patients circulating aggregated platelets were measured one year after the MI. Elevated values were found in all of them (mean +/- SD 34.9 +/- 9.1%). In 6 of the 18, all heavy smokers, extreme values were found in the range of 39-55%. Three out of the 30 patients died within five years after their first MI. The other 15 patients developed complications, most of them angina pectoris. Five patients were hospitalized for reinfarction. None of the 30 underwent aortocoronary bypass operation.(ABSTRACT TRUNCATED AT 250 WORDS)