Physiologic Studies Following Surgical Correction of Ventricular Septal Defect

Abstract

Sixteen patients were studied immediately and for 3 days following surgical closure of ventricular septal defect. In eight patients with absent or mild pulmonary vascular disease, convalescence was uneventful and only small deviations from normal in cardiac output, blood gas levels, and acid-base profile were observed. The remaining eight patients had pre-existing moderate or severe pulmonary vascular disease. Values for cardiac output were abnormally low at some time in the postoperative period in all but two of these eight patients. Failure to survive was clearly related to a low cardiac output in four of the five nonsurvivors. Reduction in cardiac output observed in this group of patients is believed to be based in major part on the pre-existing increased resistance to blood flow through the pulmonary vascular bed and also to impaired right ventricular function following operation. No evidence was obtained to suggest that major changes in pulmonary vascular resistance occurred in the immediate postoperative period in patients with moderate or severe pulmonary vascular disease following closure of ventricular septal defect. Right ventricular function following atriotomy or transverse ventriculotomy was less impaired than after vertical ventriculotomy.