The body surface isopotential maps of the non-transmural infarctions--a simulation study of excitation spread in a ventricular model.

Simulation by a digital computer of excitation spread in a human ventricular model produced displays of body surface isopotential maps. Localization of model myocardial infarctions to non-transmural and transmural sites produced distinctive differences in these displayed isopotential maps. The body surface directly over the infarcted lesion was negative in potential only in the first half period of the QRS complex and then became positive. The model demonstrated that this later positive potential was due to delayed arrival of excitation to the subepicardial layer outside of the subendocardial lesion. While, in transmural infarction, the overlying body surface remained negative in potential throughout the QRS complex. It is expected that body surface isopotential maps will become clinically available and will permit helpful differential diagnoses between non-transumral and transmural myocardial infarctions.