Correlation between electrocardiographically and enzymatically estimated infarct size and its relation to clinical course in inferior myocardial infarction.

In 194 patients with inferior wall acute myocardial infarction (MI) defined from ECG, the initial ST elevation and final Q- and R-wave changes in leads II, III and aVF were related to peak serum enzyme (heat stable lactate dehydrogenase) activity. Positive correlations were observed between initial ST elevation and peak LD (r = 0.54; p less than 0.001) and between peak LD and the final Q- and R-wave changes (r = 0.45; p less than 0.001). Peak LD activity was strongly related to the incidence and severity of congestive heart failure, and to mortality after 90 days and 2 years. A similar relationship could not be demonstrated between ECG findings and clinical outcome.