Comparison of risk factors in acute myocardial infarction and unstable angina pectoris in patients < or =66 versus >66 years of age.

A prospective study was conducted of the differences in clinical characteristics between patients with acute myocardial infarction and those with unstable angina pectoris admitted to hospitals in the South-Osaka district of Japan. Gender and smoking were identified as discriminant risk factors for the incidence of acute myocardial infarction in patients < or =66 years with acute coronary syndromes; however, age alone affected the mode of presentation in older patients.