Remote-controlled magnetic pulmonary vein isolation combined with superior vena cava isolation for paroxysmal atrial fibrillation: a prospective randomized study.

BACKGROUND: Radiofrequency ablation (RFA) of paroxysmal atrial fibrillation (PAF) has focused on pulmonary vein isolation (PVI). However, despite initial positive results, significant recurrences have occurred, partly because of pulmonary vein (PV) reconnection or non-PV ectopic foci, including the superior vena cava (SVC).

OBJECTIVES: This prospective, randomized study sought to investigate the efficacy of additional SVCI combined with PVI in symptomatic PAF patients referred for ablation.

METHODS: From November 2011 to May 2013, RFA was performed remotely using a CARTO(®) 3 System in patients randomized to undergo PVI for symptomatic drug-refractory PAF, with (PVI+SVCI group) or without (PVI alone group) SVCI. PVI and SVCI were confirmed by spiral catheter recording during ablation. Procedural data, complications and freedom from atrial tachycardia (AT) and atrial fibrillation (AF) were assessed.

RESULTS: Over an 18-month period, 100 consecutive patients (56±9years; 17 women) with symptomatic PAF were included in the study (PVI+SVCI, n=51; PVI, n=49); the CHA2DS2-VASc score was 0.9±1. Median duration of procedure (±interquartile), 2.5±1hours; total X-ray exposure, 13.3±8minutes; transseptal puncture and catheter positioning, 8±5minutes; left atrium electroanatomical reconstruction, 3±2minutes; and catheter ablation, 3.7±3minutes. After a median follow-up of 15±8months, and having undergone a single procedure, 84% of patients were symptom free, while 86% remained asymptomatic after undergoing two procedures. The cumulative risks of atrial arrhythmias (AT or AF) were interpreted using Kaplan-Meier curves and compared using the log-rank test. Long-term follow-up revealed no significant difference between groups, with atrial arrhythmias occurring in six (12%) patients in the PVI+SVCI group and nine (18%) patients in the PVI alone group (P=0.6). One transient phrenic nerve palsy and one phrenic nerve injury with partial recovery occurred in the PVI+SVCI group.

CONCLUSIONS: SVCI combined with PVI did not reduce the risk of subsequent AF recurrence, and was responsible for two phrenic nerve injuries. Accordingly, the benefit-to-risk ratio argues against systematic SVCI.