Cryoballoon or Radiofrequency Ablation for Paroxysmal Atrial Fibrillation

TLDR

Current guidelines recommend pulmonary‑vein isolation by catheter ablation for drug‑refractory paroxysmal atrial fibrillation. This multicenter, randomized trial tested whether cryoballoon ablation is noninferior to radiofrequency ablation in symptomatic patients with drug‑refractory paroxysmal atrial fibrillation. The study enrolled 762 patients, randomized 378 to cryoballoon and 384 to radiofrequency, and used a time‑to‑event analysis of first clinical failure after 90 days with a noninferiority margin of a hazard ratio of 1.43, also assessing a composite safety endpoint of death, cerebrovascular events, or serious adverse events. Over a mean 1.5‑year follow‑up, the cryoballoon group had a 34.6% event rate versus 35.9% for radiofrequency (hazard ratio 0.96, 95% CI 0.76–1.22, P<0.001 for noninferiority), and safety rates were 10.2% versus 12.8% (hazard ratio 0.78, 95% CI 0.52–1.18, P=0.24), indicating noninferiority with no significant safety difference. The trial was funded by Medtronic and registered under ClinicalTrials.gov NCT01490814.

Abstract

Current guidelines recommend pulmonary-vein isolation by means of catheter ablation as treatment for drug-refractory paroxysmal atrial fibrillation. Radiofrequency ablation is the most common method, and cryoballoon ablation is the second most frequently used technology.We conducted a multicenter, randomized trial to determine whether cryoballoon ablation was noninferior to radiofrequency ablation in symptomatic patients with drug-refractory paroxysmal atrial fibrillation. The primary efficacy end point in a time-to-event analysis was the first documented clinical failure (recurrence of atrial fibrillation, occurrence of atrial flutter or atrial tachycardia, use of antiarrhythmic drugs, or repeat ablation) following a 90-day period after the index ablation. The noninferiority margin was prespecified as a hazard ratio of 1.43. The primary safety end point was a composite of death, cerebrovascular events, or serious treatment-related adverse events.A total of 762 patients underwent randomization (378 assigned to cryoballoon ablation and 384 assigned to radiofrequency ablation). The mean duration of follow-up was 1.5 years. The primary efficacy end point occurred in 138 patients in the cryoballoon group and in 143 in the radiofrequency group (1-year Kaplan-Meier event rate estimates, 34.6% and 35.9%, respectively; hazard ratio, 0.96; 95% confidence interval [CI], 0.76 to 1.22; P<0.001 for noninferiority). The primary safety end point occurred in 40 patients in the cryoballoon group and in 51 patients in the radiofrequency group (1-year Kaplan-Meier event rate estimates, 10.2% and 12.8%, respectively; hazard ratio, 0.78; 95% CI, 0.52 to 1.18; P=0.24).In this randomized trial, cryoballoon ablation was noninferior to radiofrequency ablation with respect to efficacy for the treatment of patients with drug-refractory paroxysmal atrial fibrillation, and there was no significant difference between the two methods with regard to overall safety. (Funded by Medtronic; FIRE AND ICE ClinicalTrials.gov number, NCT01490814.).