Key result
Additional 3-minute freeze cycles after achieving pulmonary vein isolation with cryoballoon ablation did not improve freedom from atrial tachyarrhythmia at 1 year (87.3% vs 89.1%; P=0.78).
Why the study?
Although second-generation cryoballoon ablation is effective for paroxysmal AF, the ideal number of freeze cycles remains debatable.
Does an additional 3-minute freeze cycle after achieving pulmonary vein isolation with second-generation cryoballoon ablation improve freedom from atrial tachyarrhythmia in patients with paroxysmal atrial fibrillation?
RCT (n=110)
randomized
Yes
Does an additional 3-minute freeze cycle after achieving pulmonary vein isolation with second-generation cryoballoon ablation improve freedom from atrial tachyarrhythmia in patients with paroxysmal atrial fibrillation?
Absolute Event Rate: 87.3% vs 89.1%
p-value: p=0.78
An additional 3-minute insurance freeze after achieving pulmonary vein isolation with second-generation cryoballoon ablation does not improve 1-year freedom from atrial tachyarrhythmia and is unnecessary.
Additional freezes after PVI are unnecessary and can be omitted; confirms no 1-year benefit from extended cryoballoon protocols.
BACKGROUND: Pulmonary vein isolation (PVI) is a cornerstone of catheter ablation in patients with paroxysmal atrial fibrillation, and balloon-based ablation has been recently performed worldwide. The second-generation cryoballoon (CB2) ablation has proven to be highly effective in achieving freedom from paroxysmal atrial fibrillation. However, there are some debatable questions, including the ideal number of freeze cycles. METHODS: The AD-Balloon study (Multicenter Study of the Validity of Additional Freeze Cycles for Cryoballoon Ablation) was designed as a prospective, multicenter, and randomized clinical trial for investigation of the optimal strategy of freeze cycles for the CB2 ablation. One hundred and ten consecutive patients (aged 64±11 years) were randomly assigned to 2 groups after achieving a PVI by the CB2 ablation: 3-minute freeze cycles were added to each pulmonary vein (AD group: n=55) or not (non-AD group: n=55). Delayed-enhancement magnetic resonance imaging was also performed 1 to 2 months after the PVI to assess the ablation lesions. RESULTS: The patient characteristics did not differ between the 2 groups. A complete PVI was achieved in all patients. The total number of freeze cycles and durations for all pulmonary veins were significantly shorter in the non-AD group than in the AD group (5.7±1.6 versus 9.1±1.6 cycles, P<0.0001, and 932±244 versus 1483±252 seconds, P<0.0001). The cumulative freedom from any atrial tachyarrhythmia at 1 year was 87.3% in the AD group and 89.1% in the non-AD group (log-rank test P=0.78). There was no significant difference in the frequency of gaps on the PVI lines in the delayed-enhancement magnetic resonance imaging (46% in the AD group versus 36% in the non-AD group; P=0.38). CONCLUSIONS: No benefit was found in the patients receiving additional 3-minute freeze cycles after the complete PVI with the CB2 ablation, suggesting that an insurance freeze after achieving a PVI with the CB2 may be unnecessary and time consuming.
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Miyamoto et al. (2019) conducted an RCT in Paroxysmal Atrial Fibrillation (n=110). Additional 3-minute freeze cycles vs. No additional freeze cycles was evaluated on Cumulative freedom from any atrial tachyarrhythmia at 1 year (p=0.78). Additional 3-minute freeze cycles after achieving pulmonary vein isolation with cryoballoon ablation did not improve freedom from atrial tachyarrhythmia at 1 year (87.3% vs 89.1%; P=0.78).
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