Total anomalous pulmonary venous connection classifications

Associate Editors-In-Chief: ; Keri Shafer, M.D. [mailto:kshafer@bidmc.harvard.edu]

Classifications
There are four variants:
 * Supracardiac (50%): blood drains to one of the innominate veins (brachiocephalic veins) or the superior vena cava
 * Cardiac (20%): blood drains into coronary sinus or directly into right atrium
 * Infradiaphragmatic (20%): blood drains into portal or hepatic veins
 * Mixed (10%)

TAPVC can occur with obstruction, which occurs when the anomalous vein enters a vessel at an acute angle and can cause pulmonary venous hypertension and cyanosis because blood cannot easily enter the new vein as easily.