Electrocardiographic Sequelae of Right Ventriculotomy in Patients with Ventricular Septal Defects

Abstract

Right bundle-branch block appeared frequently after closure of ventricular septal defects, 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 indicates that a conduction disturbance was produced, probably as a result of interruption of pathways in the septum. These alterations are in contrast to the postoperative disappearance or regression of secondary R waves in rSR' complexes in other patients whose preoperative interpretation included incomplete right bundle-branch block. Regression of these abnormalities supports the view that right ventricular hypertrophy rather than delayed conduction through the septum was at fault in the beginning. Extensive T-wave changes in precordial [see figure in the PDF file] leads after right ventriculotomy and closure of ventricular septal defects indicate a significant alteration ventricular repolarization. The extent and duration of these abnormalities cannot be explained by 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 oxygenators were used for other operations, which did not include right ventriculotomy. Possible mechanisms for the production of the T-wave changes include injury to septal muscle from sutures, coronary air embolism, and muscle damage from the ventriculotomy itself.⁵ 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.