Persistent left superior vena cava: multi-slice CT images and report of a case.

Abnormalities of the vena cava system are usually asymptomatic and discovered incidentally during catheter placement or pacemaker implantation. Persistent left superior vena cava (PLSVC) is caused by failure of involution of the left anterior cardinal vein caudal to the left brachiocephalic vein during embryonic development. It is a benign condition, but becomes dangerous during pacemaker lead implantation, especially in emergency situations and when the right superior vena cava is absent. This is brought about by difficulty in pacemaker lead maneuvering into the right ventricle. A 64-cut multi-slice computed tomographic (MSCT) scan can show clear spatial relationship of the heart with its surrounding structures. We present a case of PLSVC discovered during pacemaker implantation, and viewed by 64-cut MSCT scan.