The purpose of the present study was to use computer simulation to investigate the applicability of body surface Laplacian mapping to the diagnosis of myocardial infarction. We have further developed a computer heart model, based on a previous 3-D finite element model which was developed in our laboratory, to simulate ventricular electrical activity and the associated body surface Laplacian maps (BSLMs). The heart model utilizes some 30,000 finite elements to represent the ventricles. Acute myocardial infarctions were simulated in the right ventricular free wall and the left ventricular free wall close to the septum. During the ST segment, the simulated BSLM showed two discrete regions of activity on the anterior chest overlying the known locations of the myocardial infractions. On the other hand, the body surface potential map (BSPM) showed a widely smoothed activity over the anterior chest not identifying the locations of the infarcted regions. The present study demonstrates that body surface Laplacian mapping may provide a means of noninvasively imaging the locations of myocardial infractions.