Biatrial drainage of right superior caval vein with preferential streaming into the left atrium.

Biatrial drainage of the right superior caval vein is an extremely rare cardiac anomaly that generally presents in childhood. We present a case of anomalous connection of the right superior caval vein with superior sinus venosus atrial septal defect and partial anomalous pulmonary venous return in a 5-month-old male presenting with unexplained cyanosis and hypoxia.