Left-Sided Superior Vena Cava

A left-sided superior vena cava is the result of a persistent left common cardinal vein. The left SVC originates from junction of left internal jugular and subclavian veins and travels along the left side of the mediastinum to (usually) drain into the coronary sinus. On rare occasions, the drainage may be to the left atrium, in which case multiple severe cardiac anomalies are also seen.

The majority of cases are associated with an absent left brachiocephalic vein. A smaller-than-normal, or, less commonly, an absent right SVC may also be seen.