Changes in the precordial electrocardiogram produced by extension of anteroseptal myocardial infarction

Abstract

Electrocardiographic studies are reported on two patients, each of whom had anteroseptal infarction, followed in a few days by lateral extension of the initial lesion. The worth of multiple precordial leads in the diagnosis of extension of such infarcts is illustrated.Evidence is again presented that infarcts which are anteroseptal in location, as shown by diagnostic changes in leads from the right precordial area, often fail to produce equally significant changes in the limb leads.It is suggested that, in cases of coronary arterial disease, some of the attacks of pain which have usually been considered prodromal symptoms of myocardial infarction, actually represent the development of a small, anteroseptal infarct, and that the more characteristic symptoms of acute coronary thrombosis which often occur later are due to an extension of this initial lesion. The true situation must be recognized, if such patients are to be properly treated.We do not wish to convey the impression that we are convinced that all attacks of so-called prodromal pain represent actual myocardial infarction. The data, at present available, bearing on this problem are inadequate to justify this conclusion. Some attacks of this character appear to be due to acute processes developing in the coronary arteries or to transient myocardial ischemia associated with such processes.