The aim of this study was to evaluate, in a large series of patients (420 males, 104 females, mean age 59 +/- 9.4 years) with acute myocardial infarction (AMI), the role of electrocardiography and two-dimensional echocardiography in identifying the site and the extension of the necrotic area, with regard to the treatment (thrombolysis or not) and the extent of coronary artery disease. Our results have shown a good correlation between ECG and echo in evaluating the infarct size, with a larger extension in echo examinations. Regarding the infarct site, a good correlation was found in anterior AMI, but not in inferior AMI. Thrombolytic therapy does not seem to introduce significant variations in this regard. Furthermore, the results of coronary angiography have shown that two-dimensional echocardiography allows us to identify the infarct-related coronary artery in a larger number of patients (90%) compared to ECG (80%). On the contrary, the two methods are similar in evaluating the extent of coronary artery disease, with correct identification of only one third of patients, the majority of them with single-vessel disease. Finally, we observed that the presence of abnormal apical wall motion is frequent (47%), in the majority of cases associated with anterior wall motion abnormalities, while in 5% of the cases the apex alone is involved. This finding suggests an analogy between these "apex infarctions" and the non Q wave infarctions, in which necrosis is present only in a little zone of a larger area at risk.