The Electrocardiographic Sequelae of Right Ventriculotomy in Patients with Ventricular Septal Defect

Abstract

The electrocardiograms of 90 patients with ventricular septal defects before and after the repair of septal defects were comparatively studied from the standpoint of possible ill effect of open heart surgery on the heart. Right bundle branch block appeared frequently after the closure of ventricular septal defects (51%), particularly in those patients who also had infundibular stenosis and in whom some of the infundibular muscle was resected. The magnitude of the postoperative changes of right bundle branch block indicate that a conduction disturbance was produced, as a result of interruption of pathways in the septum. These alterations are in contrast to the postoperative disappearance or regression of secondary R wave in rSR' complex in other patients (15.5%) whose preoperative interpretations included incomplete right bundle branch block. Regression of these abnormalities supports the view that right ventricular hypertrophy or bundle branch block rather than delayed conduction through the septum was fault in the beginning. In connection with appearance and disappearance of right bundle branch block, the mechanism of appearance of rSR' complex in the right ventricular leads was discussed.
The appearance of extensive T wave changes in the precordial leads after right ventriculotomy and closure of ventricular septal defects indicate a significant alteration in ventricular repolarization. The extent and duration of these abnormalities cannot be explained by surgical pericarditis, myocardial infarction, or the occasional development of left ventricular hypertrophy secondary to aortic insufficiency from an unsupported aortic cusp. T wave abnormalities were more common than in a smaller group of patients in whom bubble oxygenator were used for other operations which did not include injury to septal muscle from sutures, coronary air embolism, and trauma from the cardiotomy itself. Induced cardiac arrest, whether anoxic or drug induced, does not have a direct relationship to these changes. The clinical course of these patients thus far indicates that these electrocardiographic changes have no prognostic significance.