The effect of ligation of posterior coronary vessels on the electrocardiogram in experimental bundle‐branch block

Abstract

IT has been reported by Averbuck and Rachmilewitz [1931] that in dogs in which the branches descending from the circumflex ramus of the left coronary artery on the posterior surface of the heart had been ligated, section of the right branch of the His bundle no longer gave electrocardiograms typical of bundle-branch block. It is of note that an anuscesophagus lead alone was employed, and that although section of the branch was performed sometimes before, sometimes after tying the vessels, the electrocardiographic observations were always made within a few minutes or at most an hour of the ligation. The authors discussed their results, which they admitted to be surprising, at some length, and came to the conclusion that the absence of the typical picture of branch block was due to interference with the blood supply of a part of the specific conducting tissue in the left ventricle, brought about by the coronary ligatures, and that their curves were comparable to those obtained by Rothberger and Winterberg [1917] after section of the right branch and posterior division of the left branch of the His bundle.During the course of an experimental study in which the writer was associated, carried out by Wilson and his co-workers on the results of coronary ligation in the dog, the opportunity was taken to repeat the section of the right branch in dogs with various infarcts Grout, 1933a, 1933c]. The section was made always after an interval of 36-48 hours from the time of ligature, and fairly