Unusual right-to-left shunt by single-sided bilateral inferior vena cava.

Anomalous drainage of an inferior vena cava to the left atrium is a rare congenital cardiac anomaly that might lead to significant clinical implications. This report describes a 21-year-old male with an anomalous connection between one part of a single sided double inferior vena cava and the left atrium documented with cardiac imaging, including angiography. This rare congenital disorder should be considered in the differential diagnosis in patients with cyanosis and/or a history of paradoxical embolism. Interventional catheterization was the chosen method of intervention.