Persistent left superior vena cava: an intensivist's experience and review of the literature.

Persistent left superior vena cava is a relatively rare vascular anomaly. It is, however, the most common variation in the thoracic venous system. The anomaly is typically detected on chest x-ray after the placement of a pulmonary artery catheter or pacemaker leads. This report describes a case of persistent left superior vena cava detected after successful placement of a pulmonary artery catheter.