Atrioventricular septal defect

Atrioventricular septal defect, also called atrioventricular canal defect, common atrioventricular canal or endocardial cushion defect, is a heart defect in which a deficiency of the atrioventricular septum creates connections between all four chambers of the heart. It is a specific combination of three defects: an atrial septal defect, a hole in the wall between the right and left atria; a ventricular septal defect, a hole in the wall between the ventricles; and abnormalities of the mitral or tricuspid valves. It is caused by abnormal or inadequate fusion of the superior and inferior endocardial cushions with the atrial septum and the muscular part of the ventricular septum. Unlike some heart defects it does not resolve over time, and most infants need open heart surgery, which is usually successful.