Biventricular pacing via a persistent left superior vena cava: report of four cases.

Persistence of left superior vena cava (LSVC) is an uncommon finding during pacemaker implantation, which may be particularly relevant in performing LV transvenous pacing. Rarely, it is further complicated by the presence of atresia of the coronary sinus ostium (CSO). This article reports the authors experience with biventricular pacing (Biv-P) in this unusual clinical setting. From October 1999 to April 2002, 158 patients underwent biventricular pacing. In four of them (mean age 62.2 years), the presence of a persistent LSVC draining into the coronary sinus (CS) was detected at implantation, associated with atresia of the CSO in two patients. A common characteristic was the angiographic finding of a large CS with few tributaries. The LV leads were successfully positioned in the middle cardiac vein in three patients and in a posterolateral vein in one patient. All vessels were large and their cannulation via downstream CS catheterization required the lead to be manipulated through sharp angles. Mean fluoroscopic exposure and procedural times were not significantly different from the overall Biv-P population. In all patients, at a mean follow-up of 11 months, sensing and capture threshold remained stable and a significant decrease in NYHA functional class and increase in LVEF were noted. The direct lead placement in large CS tributaries in the presence of persistent LSVC was feasible and safe. The leads remained stable up to a mean follow-up of nearly 1 year.