Successive changes in the electrocardiogram following acute coronary artery occlusion.

Abstract

By the use of the portable electrocardiograph 1 it has been possible to secure a series of electrocardiograms in four patients soon after the onset of symptoms diagnostic of coronary artery occlusion. As none of these patients died, there was no opportunity to confirm the diagnosis by a pathological examination of the coronary arteries, but the diagnosis is justified by considerable experience in similar cases in which one or two characteristic electrocardiograms were obtained, which also presented typical symptoms and associated phenomena, and in which necropsy confirmed the diagnosis of acute coronary artery closure. The subsequent course in these four patients was also consistent with the original diagnosis.

In general, the electrocardiographic changes may be divided into two stages. The first stage, which was seen as early as 6 1/2 hours after the onset of original pain, consists of a well-defined deviation from the normal electrocardiogram, namely, the R-T transition, is abnormally elevated above the base line. In other words, after the completion of the R wave, the curve fails to return to the base line until the completion of the T wave. This is illustrated in Fig. 1. Indications of the electrocardiographic second stage appeared as early as 32 hours after the onset of clinical symptoms, but the change was not fully developed until the lapse of at least 12 days in one instance, and of 2 or more weeks in the others. The second stage (illustrated in Fig. 3) consists of a change in the T wave. The T wave is more definitely separated from R, due to the fact that the R-T transition approaches the base line; the T wave may be inverted, and assumes a characteristic form; i. e., the first limb is curved, the apex peaked and the second limb is rather straight.