Bonus-freeze: benefit or risk? Two-year outcome and procedural comparison of a “bonus-freeze” and “no bonus-freeze” protocol using the second-generation cryoballoon for pulmonary vein isolation

Background: Second-generation cryoballoon based pulmonary vein isolation has demonstrated encouraging acute and mid-term clinical outcome. Customarily, a bonus-freeze is applied after successful pulmonary vein isolation. Objective: To compare the long-term clinical outcome and safety profile of a bonus-freeze and a no bonus-freeze protocol. Methods: A total of 120 consecutive patients with paroxysmal [95/120 (79 %)] or persistent atrial fibrillation [25/120 (21 %)] underwent CB2-based PVI. Freeze-cycle duration was 240 s. In the first 60 patients a bonus-freeze was applied after successful PVI (group 1), while in the following 60 patients the bonus-freeze was omitted (group 2). Results: Procedure and fluoroscopy times were significantly shorter in group 2 [113.8 ± 32 vs 138.2 ± 29 min (p = 0.03) and 19.2 ± 6 vs 24.3 ± 8 min (p = 0.02)]. No differences in procedural complications were found. During a mean follow-up of 849 ± 74 (group 1) and 848 ± 101 days (group 2, p = 0.13) 69 % of patients (group 1) and 67 % of patients (group 2) remained in stable sinus rhythm without any differences between the groups (p = 0.69). Conclusions: Freedom from atrial fibrillation after second-generation cryoballoon based pulmonary vein isolation and a follow-up of >2 years is comparable when applying a bonus- and a no bonus-freeze protocol, while procedure and fluoroscopy times are significantly shorter when omitting the bonus-freeze. No differences in periprocedural complications were identified.