Supra-cardiac total anomalous pulmonary venous drainage with the four pulmonary veins are draining into a confluent chamber behind the left atrium which opens into a vertical vein that opens into the left innominate vein which opens into the markedly dilated superior vena cava (SVC).
Supracardiac type is the commonest type (50%) of the TAPVR and usually non-obstructive. Plain radiograph typically shows snowman heart (figure-of-eight heart) with the supracardiac shadow is attributed to dilated right SVC, vertical vein, and brachiocephalic vein.
Total anomalous pulmonary venous drainage is a left to right shunt and patent foramen ovale or ASD is invariably present.
The case is courtesy of Dr. Mohammad A. ElBeialy, and Dr. Heba Kamal.