Novel cryoballoon technology for atrial fibrillation ablation: Impact of pulmonary vein variant anatomy, cooling characteristics, and 1-year outcome from the CHARISMA registry

Abstract

BackgroundNo data have been reported on cooling characteristics and the impact of variant pulmonary vein (PV) anatomy on atrial fibrillation (AF) recurrences after POLARx cryoballoon (CB) ablation. ObjectiveThe purpose of this study was to analyze the impact of PV anatomy variants and cooling characteristics after CB ablation from a large multicenter prospective registry. MethodsThe primary end point was defined as 1-year absence of any atrial tachyarrhythmias (ATAs: AF/atrial flutter/atrial tachycardia). Correlation between ATA recurrences and anatomy variants/cooling characteristics were evaluated. The secondary outcome was the rate of major periprocedural complications. ResultsA total of 429 consecutive patients diagnosed with paroxysmal AF (83.4%) or persistent AF (peAF; 16.6%) were enrolled. Twenty-eight patients (6.6%) exhibited an anatomical variant (common ostium: 4.0%; adjunctive PV: 2.6%). Nadir temperature, thaw time, and total deflation time were different between standard PVs and PV variants. After the blanking period, over a mean of 431 ± 99 days of follow-up, 63 patients (14.7%) suffered an ATA recurrence. Patients with recurrences had both a shorter thaw time (18.5 ± 7 seconds vs 19.8 ± 7 seconds; P = .0012) and a shorter total deflation time, whereas time to isolation was longer (57.4 ± 42 seconds vs 49.1 ± 33 seconds; P = .04). Patients with anatomy variants showed a similar ATA recurrence rate (5 of 28 [17.9%]) to the standard anatomy group (58 of 401 [14.5%]) (P = .584), with a hazard ratio (HR) of 1.43 (95% confidence interval [CI] 0.49–4.13; log-rank, P = .4384). After adjusting for confounders, heart failure (HR 4.12; 95% CI 1.75–9.73; P = .0013) and peAF (HR 1.81; 95% CI 1.03–3.18; P = .0433) remained associated with ATA recurrence during follow-up. ConclusionThe POLARx CB system demonstrated long-term efficacy, along with a safe profile, in both patients with paroxysmal AF and those with peAF, regardless of the presence PV variants. Time to isolation was longer in patients with ATA recurrences during follow-up. Clinical Trial RegistrationCatheter Ablation of Arrhythmias with a High-Density Mapping System in Real-World Practice (CHARISMA). ClinicalTrials.gov identifier: NCT03793998. Registration date: January 4, 2019.