A new experimental porcine model for creating selective ischemia of a specific part of the myocardium while the rest of the myocardium remains free of ischemia has been used to study the electrocardiographic (ECG) changes deriving from selective ischemia of the right ventricular (RV) free wall. A patch was stitched to the ventricle to produce selective myocardial ischemic injury. In a preliminary study of nine pigs, selective ischemia of the left ventricular free wall in five and of the RV free wall in four animals was induced, and a postmortem dye injection was performed to evaluate blood flow in the area of ischemia. In an ECG study of 20 pigs, the baseline ECG was recorded with use of the standard leads I-III, aVR, aVL, and aVF, left precordial leads (V1-V6), and leads V4R, V3H, and V4H and 1 hour after inducing ischemia, the ECG study was repeated. Our experimental model produced ischemic injury in which the location and surface area were known antemortem. In the 20 pigs, ST-segment changes were recorded in leads V1-V3, V3H, and V4H. In only four pigs (20%) was ST-segment elevation recorded in lead V4R. The results show that the ECG signs of selective ischemia of the RV free wall may imitate the signs of anterior or anterolateral infarction of the left ventricle. In this study, elevation of the ST-segment in lead V4R was not pathognomonic of for RV ischemia. This model is a new tool for studying hemodynamic and ECG changes of selective univentricular or biventricular ischemic injury.