Drainage of right superior vena cava into both atria. Review of the literature and description of a case presenting with polycythemia and paradoxical embolization.

An unusual cause of polycythemia, cyanosis and paradoxical embolus is described in a 37-year-old man, consisting of a rare congenital anomaly of the superior vena cava (SVC). The right-sided SVC received pulmonary venous drainage from the right lung and drained, through two channels, into both atria with the left atrium receiving the larger of the two channels. The atrial septum was intact. Corrective surgery and postoperative cardiac catheterization are described and the literature concerning anomalies of the right superior vena cava is reviewed.