Electrocardiographic diagnosis of myocardial infarction in cases of complete left bundle branch block

Abstract

The electrocadiograms of 13 patients with myocardial infarction and left bundle branch block are analyzed. The diagnosis of the infarction was based on autopsy (6 cases), on typical electrocardiographic changes in some records without the disturbance in conduction (3 cases), and on the typical clinical syndrome and evolutive changes of the S-T segment and T wave (4 cases). The electrocardiographic changes were compared to those of 87 patients with complete left bundle branch block in whom there was no reason to suspect a myocardial infarction (autopsy in 20 cases), and also to those of 27 patients who were suffering from typical or probable angina pectoris. All the signs described in the literature as indicating a myocardial infarction in the presence of a left bundle branch block were considered. The conclusion is that only some changes in the S-T segment and the T wave (particularly if they are evolutive and not explained by the administration of digitalis) indicated with certainty a