Relationship between electrocardiographically estimated infarct size and clinical findings in inferior myocardial infarction.

In 270 patients with acute inferior wall myocardial infarction (MI) and no previous MI, Q- and R-wave changes in leads II, III, and aVF in a 12-lead standard ECG were related to the clinical course during hospitalization and 3-month follow-up. Patients with ECG-defined transmural MI showed a higher incidence of tachycardia, high degree of AV block, congestive heart failure (CHF), and pericarditis than patients with nontransmural MI. In a subgroup including 226 patients, the series was divided into quartiles according to the sum of Q- and R-wave changes in leads II, III, and aVF 4 days after arrival in hospital. A weak correlation between ECG-determined infarct size and the incidence of complications such as congestive heart failure (CHF), need for furosemide, and pericarditis, as well as the duration of hospitalization was observed. It is concluded that ECG-determined infarct size from leads II, III, and aVF in inferior MI is associated with the clinical course, although it cannot predict the outcome in the individual patient.