Total anomalous pulmonary venous return

Definition:

A congenital condition (birth defect) in which one of the four veins from the lungs to the heart (pulmonary veins) is not connected to the left side of the heart. In total anomalous pulmonary venous return (TAPVR), there is no connection of the pulmonary vein outflow to the left atrium of the heart.

Causes, incidence, and risk factors:

In normal circulation, blood is oxygenated in the lungs and then returns to the left atrium, flowing from there to the left ventricle, through the aorta, and around to the body. In total anomalous pulmonary venous return (TAPVR), oxygenated blood returns to the right atrium instead. From there it goes to the right ventricle, through the pulmonary artery and back to the lungs. In other words, blood simply circles to and from the lungs and never gets out to the body. This condition is incompatible with life.

If the infant is to live, a large atrial septal defect (ASD) or patent foramen ovale (passage between the left and right atria) must exist to allow oxygenated blood to flow to the left side of the heart and subsequently the body.

The severity of this condition depends on where the pulmonary vein connects before reentering the right atrium. Symptoms vary from severe cyanosis and heart failure to milder symptoms that do not appear until later childhood.