In 587 patients with acute myocardial infarction (AMI) and no previous MI, electrocardiographically estimated infarct size was related to 1 - and 2-year mortality. The overall mortality was higher in patients with transmural MI (Q- or R-wave changes in standard ECG) than in patients with subendocardial infarction (ST-T-wave changes in standard ECG) after 1 year (18.8% compared to 6.5% p<0.001) and after 2 years (22.2% compared to 13.8%, p=0.049). When patients who were alive during primary hospitalization were analyzed separately, slightly higher mortality was found in patients with transmural MI than in subendocardial MI after 1 year (9.6% compared to 4.2%, p =0.076) while no difference was found after 2 years (13.4% as compared to 11.7%, p>0.2). In a subgroup of patients with anterior MI, precordial mapping with 24 chest leads was analyzed 4 days after arrival in hospital (n=197). Patients were divided into quartiles according to the sum of R waves, the sum of Q waves, and the number of Q waves. There was a similar overall mortality in each quartile after 1 year and after 2 years regardless of ECG parameters studied. Neither did we find any correlation between the sum of R waves in leads II, III, and a VF on the fourth day in patients with inferior MI and overall 1 - or 2-year mortality rate, although there was a trend towards higher mortality with more ECG changes.