Catheter ablation of atrial fibrillation in patients with persistent left superior vena cava is associated with major intraprocedural complications

BACKGROUND A persistent left superior vena cava (PLSVC) is an uncommon cardiac anomaly. OBJECTIVE The purpose of this study was to assess the complication rate and procedural outcome in patients with PLSVC who were referred for catheter ablation of atrial fibrillation (AF). METHODS Between September 2006 and February 2009, seven patients referred for circumferential pulmonary vein (PV) isolation (PVI) demonstrated a PLSVC. PVI was confirmed by spiral catheter recording within the respective PVs. Ablation within the PLSVC was performed using an irrigated-tip catheter (energy settings 20 W, 43 C, flow rate 17 mL/min) or, alternatively, a cryoballoon catheter (28 mm balloon, 300-second energy application). Patients were analyzed according to procedural outcome and rate of complications. RESULTS Among seven patients (three female, mean age 57 +/- 8 years, two paroxysmal, five persistent AF, structural/congenital heart disease present in three patients, mean left atrial size 43 +/- 6 mm), 14 ablation procedures were performed. Two major complications (left phrenic nerve injury and cardiac tamponade) occurred in two of four patients undergoing PLSVC ablation. Of four of seven patients undergoing PLSVC ablation, two patients needed one and one patient needed two redo PLSVC ablation procedures. The first-time procedural success rate was 29%, while the overall success rate reached 86% after a median follow-up period of 621 (339-1,289) days. CONCLUSION In patients with ectopic activity from a PLSVC, the ablative strategy should include isolation of the PLSVC as a procedural endpoint, although multiple ablation procedures may be necessary to achieve stable sinus rhythm. Contrary to previous reports, complications are common if the PLSVC is targeted for ablation.