The Concept of "Masquerading" Bundle-Branch Block

Abstract

This is a clincopathologic study of 2 patients who presented so called "masquerading" bundle-branch block in their ecgs. The conduction systems and the entire hearts of these patients were studied pathologically by methods especially devised by Lev for ecg correlation. In each case, bilateral bundle-branch lesions of considerable intensity were demonstrated which did not completely disrupt the continuity of the branches. Each case revealed extensive destruction of the interventricular septum, the free walls of the left ventricle, and marked bilateral ventricular hypertrophy. It is suggested that the ecg complex "masquerading", bundle-branch block is the result of partial bilateral bundle-branch block, and that the term "masquerading" bundle-branch block be discarded.