Comparison of Single-Freezing Temperature-Guided and Conventional Time-to-Isolation-Guided Protocols of Cryoballoon...

The study aimed to compare the efficacy and safety of simplified single-freezing protocol with achieving -40 °C within 60 s of freezing as the observation index and the conventional time-to-isolation (TTI)-guided double-freezing protocol using second-generation cryoballoon in the treatment of atrial fibrillation (AF).

A retrospective analysis was performed. After propensity score matching, 146 patients who underwent conventional TTI-guided protocol freezing (conventional group) and 146 patients who underwent single-freezing temperature-guided protocol freezing (simplified group) using second-generation cryoballoon were included. Procedure time, X-ray time and dose, complications, success rate, and recurrence rate during follow-up were analyzed.

Compared with the conventional group, the simplified group showed a significant reduction in procedure time (98.8 ± 16.3 vs. 79.4 ± 12.7 min, P < 0.001), and X-ray time (24.3 ± 6.8 vs. 17.8 ± 4.9 min, P < 0.001) and dose (681.1 ± 337.8 vs. 540.1 ± 343.7 mGy, P < 0.001). There was no significant difference in the success rate of acute pulmonary vein isolation between the two groups of patients (145/146 vs. 146/146, P = 0.975) and the proportion of maintaining sinus rhythm during follow-up (114/146 vs. 109/146, P = 0.842). Cox regression analysis showed that simplified protocol is not a predictive factor for recurrence in AF cryoablation.

In summary, the single-freezing temperature-guided protocol demonstrates comparable efficacy and safety to conventional TTI-guided protocol of second-generation cryoballoon in the AF ablation with the advantages of reducing procedure time and radiation exposure.