In a normal heart, oxygen-rich blood travels from the lungs back to the left side of the heart through the pulmonary veins. From there, the blood is pumped through the aorta to nourish the tissues and organs of the body. Oxygen-poor blood is then pumped to the right side of the heart, where it is sent through the pulmonary artery to the lungs to receive oxygen.

Total anomalous pulmonary venous return (TAPVR) is a congenital heart defect in which one or all of the pulmonary veins between the lungs and heart are not connected properly. Instead of going to the left side of the heart, these veins return oxygen-rich blood back to the right side of the heart, where the blood is once again pumped back into the lungs. As a result of this cycle, oxygen–rich blood is unable to reach the tissues and organs of the body. 

TAPVR is a serious malformation that results in death if untreated. For most babies, survival with TAPVR depends on the presence of other heart defects that allow some mixing of oxygen-rich and oxygen-poor blood in the right and left sides of the heart. This allows at least some oxygen-rich blood to reach the body, although not usually enough to prevent serious complications.

TAPVR is treated with open-heart surgery. In most cases, this surgery will be performed as rapidly as possible, although there are some instances in which TAPVR does not present symptoms until later in childhood.

Surgical repair consists of reconnecting the pulmonary veins to their normal position in the left atrium and repairing any other heart defects that may be present. Early surgical repair usually gives excellent results, provided there are no additional heart defects.