Long-term outcomes of a time to isolation - based strategy for cryoballoon ablation compared to radiofrequency ablation in patients with symptomatic paroxysmal atrial fibrillation.

Background: Cryoballoon ablation (CBA) is one of the most commonly used technologies designed for pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF), although the dosing of CBA remains controversial. We evaluated the long-term efficacy and safety of a novel individualized strategy of CBA compared to radiofrequency ablation (RFA) for patients with PAF.

Methods: In this observational study, symptomatic patients with drug-refractory paroxysmal AF were prospectively consented and enrolled in four centers, being assigned either to the CBA or RFA arm for ablation. In the CBA group, we used a time to isolation (TTI) - based dosing protocol. The primary endpoint was the recurrence of atrial arrhythmia >30 s following a 90-day blanking period. The secondary endpoint was procedure-related complications and procedure parameters.

Results: A total of 500 patients were recruited in either the CBA group (n = 247) or the RFA group (n = 253) between January 2017 and July 2018. After a median follow-up of 778 days, the atrial tachyarrhythmia-free survival was 71.7% in the CBA group and 67.0% in the RFA group. CBA and RFA displayed similar major or minor complication occurrence, while the former had a significantly shorter procedure duration (82.5 min vs. 141.1 min, p < .001) and left atrial dwell time (60.1 min vs. 109.9 min, p < .001) but longer fluoroscopy exposure (13.8 min vs. 8.1 min, p < .001).

Conclusion: Compared to RFA, our TTI-based CBA dosing protocol showed comparable efficacy and safety, with a significantly reduced procedure duration in patients with PAF.