The most common types include Return via an ascending left vertical vein that drains to the innominate vein or to the superior vena cava (supracardiac TAPVR) A descending vein that drains infradiaphragmatically to the portal circulation (infracardiac TAPVR) Connection of the pulmonary vein confluence to the coronary sinus (cardiac TAPVR) The infradiaphragmatic drainage type is invariably severely obstructed, leading to dramatic pulmonary edema and cyanosis unresponsive to supplemental oxygen that manifest shortly after birth.