Ventricular Septal Defect (VSD) means there is a hole in the heart. The hole occurs in the wall (septum) that separates the heart's lower chambers (ventricles) and allows blood to pass from the left to the right side of the heart. The oxygen-rich blood then gets pumped back to the lungs instead of out to the body.
A ventricular septal defect happens during pregnancy if the wall that forms between the two ventricles does not fully develop, leaving a hole. A ventricular septal defect is one type of congenital heart defect.
In a baby without a congenital heart defect, the right side of the heart pumps oxygen-poor blood from the heart to the lungs, and the left side of the heart pumps oxygen-rich blood to the rest of the body.
In comparison, in a baby with a ventricular septal defect, blood often flows from the left ventricle through the ventricular septal defect to the right ventricle and into the lungs.
This extra blood being pumped into the lungs forces the heart and lungs to work harder.
Over time, if not repaired, this defect can increase the risk for other complications, including heart failure, high blood pressure in the lungs (called pulmonary hypertension), irregular heart rhythms (called arrhythmia), or stroke.