Ventricular septal defect

(VSD); a hole (defect) in the wall that separates the lower chambers of the heart

Description
The lower chambers of the heart are called the ventricles and the wall between them the ventricular septum. In the normal heart, the septum prevents blood from flowing directly from one ventricle to the other. In a heart with a VSD, blood can flow directly between the two ventricles, lowering the efficiency of blood circulation and oxygen transport from the lungs to the periphery.