Transvenous pacemaker implantation via a unilateral left superior vena cava.

A 72-year-old man with a unilateral left superior vena cava and anomalous drainage of the inferior vena cava required permanent pacing. The anomalies were verified by venography and cardiac catheterization. Difficulties in implantation of a temporary and permanent pacemaker are described. A transvenous endocardial lead was placed in a stable position in the right ventricle. The pacemaker system has now functioned normally for 32 months.