Central venous catheterization via persistent left superior vena cava.

We describe the problems of clinical assessment of subclavian catheter placement whose course was noted to be along the left lateral border of the heart, suggesting malposition. After the catheter's position in a persistent left superior vena cava was confirmed by blood gas analysis, lateral chest X-ray film, and venography, the catheter was used to provide total parenteral nutrition without complications. The evaluation and workup of seeming malposition of central venous catheters and the embryologic development of a left-sided vena cava are discussed.