Single 3-Minute versus Double 4-Minute Freeze Strategy for Second-Generation Cryoballoon Ablation: A Single-Center Experience.

Introduction: Second-generation cryoballoon (CB-Adv) ablation is highly effective in achieving pulmonary vein isolation (PVI) with promising mid-term clinical outcome. However, the ideal freezing strategy is still under debate. The aim of this study was to assess the efficacy of a single 3-minute approach compared to the conventional 4-minute plus bonus application using CB-Adv.

Methods And Results: One hundred and sixty patients (67% male; mean age 58.0 ± 13.3 years) underwent PVI using CB-Adv for paroxysmal atrial fibrillation (PAF). Among 160 patients, 80 received a single 3-minute approach (3-mns group), while the remaining 80 conventional 4-minute plus bonus-freeze (4-mns group). Mean procedure and fluoroscopy times were 90.6 ± 15.8 and 18.3 ± 6.9 in the 4-mns group, 75.2 ± 17.1 and 13.5 ± 8.7 in the 3-mns group (P < 0.001, respectively). First-freeze isolation rate was 91.6% in the 4- versus 90.6% in the 3-mns group (P = 0.78). Persistent phrenic nerve palsy (PNP) occurred in 6/80 (3.5%) in the 4-mns group and 4/80 in the 3-mns group (P = 0.75). The overall freedom from ATas 2 years after the procedure was 78.1% (125/160): 77.5% (62/80 patients) in the 3-mns and 78.8% (63/80 patients) in the 4-mns group (P = 0.82). In multivariate analysis, time to PVI and nadir temperature independently predicted ATa recurrences (P < 0.001).

Conclusions: CB-Adv ablation for PAF is highly effective, resulting in 78% 2-year freedom from arrhythmic recurrences. A "single 3-minute strategy" showed equal efficacy as compared to the conventional 4-minute plus bonus freeze approach at 2-year follow-up, providing shorter procedure and fluoroscopy time. Nadir temperature and time to PVI were predictors of arrhythmic recurrences. "Bonus-freeze" strategy might be unnecessary.