Implantation of a biventricular pacing system in a patient with a persistent left superior vena cava.

The presence of a persistent left superior vena cava was encountered in a 64-year-old man undergoing implantation of a biventricular pacing system. Leads with active fixation were positioned in the right atrium and right ventricle, through the persistent left superior vena cava and the proximal segment of the coronary sinus. For left ventricular pacing, a standard bipolar lead was positioned directly in the posterior branch of the coronary sinus without the use of special guiding catheters.