The Influence of the Ventriculotomy Site

EXPERIENCES in the surgical research laboratory and in the operating room have served to refine the technic of open cardiotomy for the repair and correction of anomalies involving the ventricular septum, the right ventricular outflow tract, and the pulmonary valve. These refinements have been reflected in a steadily declining mortality following the repair of ventricular septal defects and the correction of Fallot 's tetralogy.1 2 There remains, however, a group of patients with these lesions in whom surgery continues to be hazardous. In this group right ventricular pressures are high preoperatively and right ventricular work burden remains increased postoperatively. This includes patients with ventricular septal defects in whom the pulmonary artery pressure preoperatively was 70 per cent or more of the systemic pressure, particularly when this was associated with high pulmonary vascular resistance.3 It embraces some of those with Fallot's tetralogy in whom, because of incomplete relief of outflow tract obstruction, the right ventricular pressure remains elevated.4 And, finally, there should be included certain patients who had incomplete repairs of ventricular septal defects in association with infundibular stenosis.5 One factor that these patients have in common is the persistence postoperatively of increased right ventricular work loads. Clinical observations and physiologic considerations suggest that postoperative morbidity