Complete atrioventricular canal defect (CAVC) is a heart condition in which there is a large hole in the center of the heart and only one heart valve. Normally, the heart is divided into four chambers, and there is one valve on each side of the heart. The chambers on the right side of the heart receive blood from the body and pump it to the lungs where the blood gets oxygen. The chambers on the left side of the heart get the oxygen-rich blood from the lungs and pump it back out to the body. In CAVC, the blood in the chambers mix, and the heart valve may not close tightly. This makes the heart work much harder than normal.
CVAC is a problem that is present at birth (congenital heart defect). Children with CAVC usually start to have