ventricular septal defect

ventricular septal defect A hole in the wall (septum) between the lower chambers of the heart (ventricles). Abbreviated VSD. VSDs are the most common birth defect that involves malformation of the heart. At least 1 baby in every 500 is born with a VSD. A VSD shunts blood from the left ventricle, where it is under relatively high pressure, into the right ventricle, which has to do extra work to handle the additional blood. The right ventricle may have trouble keeping up with the load, enlarge, and fail. The lungs also receive too much blood under too great pressure. The small arteries (arterioles) in the lungs thicken up in response, and permanent vascular damage can be done to the lungs. VSDs that are small permit only minimal shunting of blood, so the pressure in the right ventricle remains normal and the heart and lungs function normally. Surgical repair is not recommended for small VSDs since many close on their own over time. With a large VSD there is a significant shunt into the right ventricle, excessive blood flow into the lungs, and elevated pressure in the arteries to the lungs (pulmonary hypertension). Surgery should be done to close a large VSD. The prognosis for patients with VSD is generally excellent.