Left-to-right shunt via left superior vena cava communication with left atrium.

The findings in a 22-year-old man with Ebstein's anomaly of the tricuspid valve, Wolff-Parkinson-White syndrome, and a persistent left superior vena cava are reported. This is the first reported case of this combination of anomalies in which the atrial septum was intact and the left superior vena cava communicated with the left atrium. Uniquely, blood was shunted left to right via the left superior vena cava from the left atrium. Only one previous case of left-to-right shunting via a left superior vena cava (in the absence of mitral valvular disease or cor triatriatum) has been reported (associated with aortic coarctation). Angiograms demonstrated the left atrial connection of the left superior vena cava to be at the entrance of the right superior pulmonary vein into the left atrium. In the absence of demonstrable left-sided heart disease, this anatomic juxtaposition is suggested as a possible explanation for the direction of shunting.