The efficacy at 1 year of pulmonary vein isolation (PVI) after atrial fibrillation (AF) ablation was found to be comparable when using radiofrequency ablation guided by tissue contact-force (CF-RF) and cryoballoon ablation, according to study results published in Circulation.

In this multicenter prospective single-blinded randomized CIRCA-DOSE study ( identifier: NCT01913522), adult patients with symptomatic paroxysmal n AF refractory to ≥1 class I or class III antiarrhythmic drug and who were referred for a first catheter ablation procedure were enrolled. All study participants underwent continuous arrhythmia monitoring with an implantable loop recorder.

Patients were randomly assigned to receive standard CF-RF (n=115), a 2-minute cryoballoon ablation duration (CRYO-2; n=115), or a standard 4-minute cryoballoon ablation duration (CRYO-4; n=116). The study’s primary outcome was time to first documented recurrence of symptomatic or asymptomatic atrial tachyarrhythmia (including AF, atrial flutter, and atrial tachycardia) between days 91 and 365 after ablation or the occurrence of a repeat ablation procedure during the 12-month follow-up. Freedom from symptomatic arrhythmia and AF burden during follow-up were the study’s secondary outcomes.

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The 1-year freedom from atrial tachyarrhythmia (CF-RF, 53.9%; CRYO-4, 52.2%; and CRYO-2, 51.7%; P =.87) and the 1-year freedom from symptomatic atrial tachyarrhythmia (CF-RF, 79.1%; CRYO-4, 78.2%; and CRYO-2, 73.3%; P =.26) were comparable in the 3 groups.

The median reduction in AF burden at follow-up was comparable between groups (CF-RF, 99.3%; interquartile range, [IQR], 67.8-100.0%; CRYO-4, 99.9%; IQR, 65.3-100.0%; CRYO-2, 98.4%; IQR, 56.2-100.0%; P =.36). The percentage of patients who experienced serious adverse events was 2.6% in the CF-RF group, 5.3% in the CRYO-4 group, and 6.0% in the CRYO-2 group (P =.24). Although patients in the CR-RF group had a longer procedure, they also had a shorter exposure to fluoroscopy compared with patients in the cryoballoon groups (P <.001).

Study limitations include its lack of generalization to patients with more advanced and non-paroxysmal forms of AF.

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 “PVI performed by cryoballoon ablation or by contact-force guided radiofrequency ablation results in comparable freedom from recurrent atrial tachyarrhythmia,” concluded the study authors.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Andrade JG, Champagne J, Dubuc M, et al; CIRCA-DOSE Study Investigators. Cryoballoon or radiofrequency ablation for atrial fibrillation assessed by continuous monitoring: a randomized clinical trial. Circulation. 2019;140(22):1779-1788.