Left Atrial Drainage of a Persistent Left Superior Vena Cava.

Although the most common form of the persistent left superior vena cava anomaly is usually clinically silent and often discovered incidentally, the risk of developing cyanosis, heart failure, and embolic cerebrovascular events is high among cases where the anomaly causes a right to left shunt. A rare case of persistent left superior vena cava draining into the left atrium through the superior left pulmonary vein is presented with a discussion of the embryology, morphologic forms, and clinical significance of the persistent left superior vena cava.