Atrial fibrillation progression after cryoablation versus radiofrequency ablation: the CIRCA-DOSE trial

Abstract

Background and aims: Atrial fibrillation (AF) is a chronic, progressive disorder. Persistent forms of AF are associated with increased rates of thromboembolism, heart failure, and death. Catheter ablation modifies the pathogenic mechanism of AF progression. No randomized studies have evaluated the impact of the ablation energy on progression to persistent atrial tachyarrhythmia.

Methods: 346 patients with drug-refractory paroxysmal AF were enrolled and randomized to contact-force guided radiofrequency ablation (CF-RF ablation, n = 115), 4-minute cryoballoon ablation (CRYO-4, n = 115), or 2-minute cryoballoon ablation (CRYO-2, n = 116). Implantable cardiac monitors placed at study entry were used for follow-up. The main outcome was the first episode of persistent atrial tachyarrhythmia. Secondary outcomes included atrial tachyarrhythmia recurrence, and arrhythmia burden on implantable monitor.

Results: At a median of 944.0 (interquartile range [IQR], 612.5-1104) days, 0 of 115 patients (0.0%) randomly assigned to CF-RF, 8 of 115 patients (7.0%) assigned to CRYO-4, and 5 of 116 patients (4.3%) assigned to CRYO-2 experienced an episode of persistent atrial tachyarrhythmia (P = 0.03). A documented recurrence of any atrial tachyarrhythmia ≥30 seconds occurred in 56.5%, 53.9%, and 62.9% of those randomised to CF-RF, CRYO-4, and CRYO-2, respectively (P = 0.65). Compared to the pre-ablation monitoring period, AF burden was reduced by a median of 99.5% (IQR 94.0-100.0%) with CF-RF, 99.9% (IQR 93.3-100.0%) with CRYO-4, and 99.1% (IQR 87.0-100.0%) with CRYO-2 (P = 0.38).

Conclusions: Catheter ablation of paroxysmal AF using radiofrequency energy was associated with fewer patients developing persistent AF on follow-up.

Keywords: Ablation; Atrial fibrillation; Cryoablation; Insertable cardiac monitor; Pulmonary Vein Isolation; Radiofrequency Ablation; implantable loop recorder.