Pacemaker electrode implantation in patients with persistent left superior vena cava.

Four out of 661 consecutive patients with permanent endocardial VVI pacing had the pacing lead introduced through a persistent left superior vena cava. It was difficult to introduce the lead from the right atrium into the right ventricle because the tip of the lead tended to be deflected away from the tricuspid orifice. This difficulty was overcome by shaping the lead into a pigtail with 3-4 cm wide loop. This avoided the risk of entering a branch of the coronary sinus in order to reach the right atrium. This technique made it easier to position the lead in the right ventricular apex. There were no complications in these four patients during a mean follow up of three years.