Aetiological and prognostic correlates of site of myocardial infarction

Abstract

This is a study of the relationship between the site of infarction and both risk factors and in-hospital outcome in 745 consecutive patients admitted with a first myocardial infarction. Patients with anterior infarctions were significantly more likely never to have smoked than patients with inferior infarctions. They had a higher prevalence of hypertension and a higher mean cholesterol level. In hospital prognosis was worse in anterior infarctions, with significantly higher rates of death and complications. Atrioventricular blocks were more common in inferior infarctions. Non-Q-wave infarctions had a lower incidence of complications than Q-wave infarctions. There was no difference in risk factor levels between Q-wave and non-Q-wave infarctions. Anterior and inferior infarctions were of similar size. Non-Q-wave infarctions were significantly smaller. A logistic regression showed a negative relationship between in-hospital mortality and smoking, and a positive one with peak cardiac enzyme levels. Any effect of site of infarction on mortality was eliminated when corrected for these factors. Our data indicate that the adverse prognosis associated with anterior myocardial infarction is related to differences in aetiology rather than to infarction size.