Pulmonary veins anatomical determinants of cooling kinetics during second-generation cryoballoon ablation

Aim: The aim of the study was to investigate the role of anatomical characteristics of the pulmonary veins (PVs) determining cooling kinetics during second-generation cryoballoon ablation (CbA). Methods and Results: we enrolled all consecutive patients who underwent CbA for symptomatic atrial fibrillation in our center from January 2019 to March 2019. All patients had complete computed tomography scans of the heart before the ablation. Anatomical characteristics were tested for prediction of a nadir temperature (NT) ≤ −48°C. Significant differences were noted among PV max diameter (20.8 ± 2.8 vs 18.5 ± 2.5 mm; P <.001); PV minimum diameter (15.2 ± 3.0 vs 13.0 ± 3.1 mm; P <.001); PV area (268.1 ± 71.9 vs 206.2 ± 58.7 mm ²; P <.001); PV ovality (1.4 ± 0.3 vs 1.5 ± 0.3; P =.005); and PV trunk length (27.4 ± 7.4 vs 21.3 ± 6.5 mm; P <.001). A scoring system was created by assigning one point each ranging from 0 (best anatomical combination) to 5. In the group with a score of 0, 94.0% of the CbA could reach a NT ≤ −48°C whereas with a score of 5, only 29.0% (P <.001). Left superior pulmonary vein with short trunk length and acute angle of PV branch was significantly associated with warmer NT (11.8% satisfactory CbA; P =.003). Regarding right inferior pulmonary vein, trunk length (P =.004), maximum diameter (P =.044), and transverse angle (P =.008) were independently associated with good NT. Conclusion: Anatomical PV features are associated with cooling kinetics and an anatomical score could predict lower NT during second-generation CbA. Specific characteristics were identified for inferior PV. Although heart imaging is not mandatory prior CbA, it can be a useful tool to predict cooling kinetics.