Electrocardiographic body surface mapping on admission to coronary care has been shown to predict prognosis in a previous study of 100 patients with inferior wall acute myocardial infarction (AMI). A further 98 patients with first inferior wall AMI were now studied by body surface mapping on admission to coronary care to confirm that both the spatial distribution or map pattern of ST-segment potentials and the precise measurement of the maxima and minima are of prognostic significance. Each ST-segment map was compared by correlation coefficient to the average map pattern of the 4 groups derived in a previous study and placed in the group with the highest correlation coefficient. Analysis of these groups against outcome confirmed that the group dominated by a large area of marked anterior ST depression was associated with a high rate of complications and a significantly lower survival free of coronary artery bypass grafting (p less than 0.01). Patients in this group had more extensive and severe coronary artery disease than patients in the other groups. Increasing values of maximal ST depression correlated with mortality and complication rates. The extent by which the magnitude of ST-segment depression exceeded the magnitude of ST-segment elevation correlated with mortality and incidence of left ventricular failure. The results confirm the findings of the original study. Body surface mapping is of prognostic significance in inferior wall AMI.