Creation of a Ventricular Septal Defect

Abstract

Defects in the ventricular septum may be in either the muscular or the membranous portion. The membranous defects are more common and occur when the membranous portion of the ventricular septum fails to fuse properly with the muscular portion in the developing embryo. The functional result of interventricular defects is a left-to-right shunt, with a large portion of the blood from the left ventricle going directly into the right ventricle. Over a period of time the right ventricle undergoes hypertrophy, and pulmonary hypertension develops. Late in the course of the disease cardiac failure occurs, and cyanosis may develop as a result of the reversal of flow.