THE NATURAL HISTORY OF VENTRICULAR SEPTAL DEFECT

Abstract

Seventy-five patients were studied in whom the diagnosis of ventricular septal defect was accepted after cardiac catheterization. Approximately 1/3 had central cyanosis even at rest with an arterial O2 saturation under 90%. These tended to be evenly distributed by decades from infancy to 40 years of age. In acyanotic patients, the heart was enlarged in the presence of a raised pulmonary pressure and a large or moderate shunt. This was much less common among cyanotic cases. Pulmonary regurgitation was diagnosed in 20% of the patients. The pulmonary blood flow in the 51 patients whose data were available ranged from below normal (in patients with veno-arterial shunts) to values that were too large to be accurately measured. The pressure differential between the ventricles was generally small (10-20 mm Hg) enabling the heart to maintain a reasonable systemic flow despite a large shunt. The right ventricular and pulmonary artery pressures were already high in small children probably from birth[long dash]the systolic pressure tended to increase with age more than the diastolic pressure. It is believed that the classification of ventricular septal defects should depend on the size and direction of the shunt and the level of the pulmonary arterial resistance.