Duty-cycled bipolar/unipolar radiofrequency ablation for symptomatic atrial fibrillation induces significant pulmonary vein narrowing at long-term follow-up

Abstract

A novel duty-cycled bipolar/unipolar ablation catheter pulmonary vein ablation catheter (PVAC) has been developed to achieve pulmonary vein (PV) isolation in patients with atrial fibrillation (AF). Ablation with PVAC was recently found to induce PV narrowing at 3 months follow-up. The long-term effects of this catheter on PV dimensions are however unknown and were evaluated with this study. Patients (n = 62, 71% male, age 60 ± 7 years) with drug-refractory AF scheduled for a first ablation procedure were evaluated. A multi-slice computed tomography (MSCT) scan was performed before and 1 year after the initial procedure. Pulmonary vein dimensions and left atrial (LA) volume were measured on MSCT. To correct for reverse remodelling of the LA, the ostial area/LA volume ratio before and after PVAC was calculated. As reverse remodelling may depend on procedural outcome, patients were divided in two groups depending on sinus rhythm (SR) maintenance or AF recurrence 1 year after ablation. Baseline characteristics were comparable between the SR group (n = 41) and the AF recurrence group (n = 21). At one year follow-up, ostial area of the PVs (n = 219) was significantly reduced from 236 ± 7.0 to 173 ± 7.4 mm(2) (27% narrowing, P < 0.01), independent of ablation outcome. Pulmonary vein narrowing was mild in 37% of PVs (25-50%), 9% was moderate (50-70%), and 3% severe (>70%). Left atrial volumes were found to be significantly reduced after ablation (14 and 5% for the SR group and AF recurrence group, respectively, P < 0.01). After adjustment for LA volume reduction, narrowing of PV ostial area remained significant in these patients (P < 0.01). Ablation with PVAC results in a significant decrease in PV dimensions after long-term follow-up. In line with previous literature, PV narrowing was mild and patients did not develop any clinical symptoms.