The availability of potent, but potentially dangerous, types of reperfusion therapy for acute myocardial infarction (AMI) has forced us to refine our tools for early and accurate diagnosis and for early risk stratification of patients with evolving AMI. The estimation of risk has to be made shortly after admission, when only the history, physical examination, and the ECG are available. This study was undertaken to compare in-hospital mortality with different patterns of the ECG obtained at admission in 147 consecutive patients with an evolving first AMI of the anterior wall. By using a new classification of the admission ECG, it was possible to divide the patients into 3 groups: (1) group A contained 12 patients with tall peaked T waves in the involved leads, without ST segment elevation; (2) group B comprised 77 patients with abnormal T waves and ST elevation, but without major changes in the terminal portion of the QRS complex; and (3) group C comprised 58 patients with abnormal T waves, ST elevation, and distortion of the terminal portion of the QRS. The mortality was 0, 3 percent, and 29 percent in groups A, B, and C, respectively (χ2=22.91; p=0). By using a logistic regression model, it was found that the initial ECG pattern alone is a strong predictor of in-hospital mortality in patients with an evolving anterior wall AMI. The predicted probabilities of death in groups A, B, and C are 0.0016, 0.025, and 0.29, respectively. This simple classification of the initial ECG pattern in patients with a first AMI of the anterior wall may enable the differentiation of patients with low in-hospital mortality (groups A and B) and of those with an in-hospital mortality of almost 30 percent (group C).