Total anomalous pulmonary venous return is a structural problem
with the heart that causes oxygen-poor blood. It is a type of congenital heart
defect, which means it develops before a baby is born.
With this defect, all the pulmonary veins from the lungs do not
connect with the left side of the heart as they should. Instead, they connect
to veins or structures that drain into the right side of the heart. This
results in oxygen-rich blood flowing back into the right side of the heart.
The left side of the heart and the body get some oxygen-rich blood
because of other defects that are usually present, including:
Atrial septal defect, which is an opening in
the wall (septum) between the upper chambers (atria) of the heart.
Foramen ovale, which is an opening between the two upper chambers
(atria) of the heart. This opening (which is present in the fetus but normally
closes at birth) remains open in total anomalous pulmonary venous
John Pope, MD - Pediatrics & Larry A. Latson, MD - Pediatric Cardiology