Because the leads showing ST segment elevation on the body surface ECG will directly overlie the acutely ischemic myocardium, they serve as a means to identify the location of the acute transmural ischemia and, by inference, to suggest the location of the culprit lesion within the coronary circulation.
The table shown here illustrates this relationship. The leads identified as V3R and V4R are chest leads placed to the right of the sternum. These are discussed later.