Total anomalous pulmonary venous return

Total anomalous pulmonary venous return

In total anomalous pulmonary venous return, the pulmonary veins attach to the heart in incorrect places, instead of attaching correctly to the heart's left atrium. This causes oxygen-rich blood returning to the heart from the pulmonary veins to flow into the heart's right atrium, and mix with oxygen-poor blood either before entering the heart or in the right atrium. In a normal heart, as shown on the left, oxygen-rich blood from the pulmonary veins returns to the left atrium.