Thawing plateau time indicating the duration of phase transition from ice to water is the strongest predictor for long-term durable pulmonary vein isolation after cryoballoon ablation for atrial fibrillation—Data from the index and repeat procedures

Introduction This study aimed to clarify the relationship between the durability of pulmonary vein (PV) isolation and the time of phase transition from ice to water indicated by thawing plateau time in a cryoballoon ablation for atrial fibrillation (AF). Methods and results In this retrospective study, 241 PVs from 71 patients who underwent a repeat AF ablation 526 (IQR: 412, 675) days after a cryoballoon ablation were analyzed. Reconnection was observed in 101 (41.9%) PVs of 53 patients (74.6%). Thawing plateau time (Time TP ) was defined as the time from 0°C to 10°C inside the balloon in the thawing period. Durable PV isolation was associated with significantly longer Time TP compared with PV reconnection (26.0 vs. 11.0 s, P < 0.001). The proportion of durable PV isolations increased with Time TP in a dose-proportional manner. The cut point for PV reconnection was Time TP <15 s with a positive predictive value of 82.1% (sensitivity = 63.4%, specificity = 90.0%) while for durable PV isolation the cut point was Time TP >25 s with a positive predictive value of 84.6% (sensitivity = 55.0%, specificity = 86.1%). In the analysis of multivariable logistic regression, location of PV reconnection ( P < 0.01), Time TP ( P < 0.05) and thawing plateau integral ( P < 0.01) were shown as independent predictors for durable PV isolation. Conclusion Time TP is an independent predictor for the durability of PV isolation, and it presents in a dose-proportional manner. Time TP <15 s predicts long-term reconnection while Time TP >25 s predicts durable PV isolation.