Total anomalous pulmonary venous return

Total anomalous pulmonary venous drainage is a cyanotic condition with intracardiac mixing in which the pulmonary veins collect in a confluence behind the heart but then fail to drain into the left atrium. Drainage occurs either directly or indirectly to the right side of the heart. This anomalous venous drainage may occur via a variety of routes:

• supracardiac - drainage is to the innominate vein or the right superior vena cava.
• cardiac - drainage is to the coronary sinus or the right atrium directly.
• infracardiac - anomalous drainage is to the portal vein or the inferior vena cava.

This condition is always associated with an atrial septal defect.