Three-year follow-up results of cryoablation of atrial fibrillation patients：A comparison of 1st-generation and 2nd-generation cryoballoons

objective: Both first and second generation cryoballoons (CB1 and CB2) are efficient and safe treatments for patients with atrial fibrillation (AF). However, the superiority of CB2 over CB1 remains controversial. Our purpose was to compare ablation outcomes and complications between two generation CB especially in the long-term follow-up and in Chinese population. Methods: 278 consecutive patients underwent CB ablation were included, with 139 cases of 1st and 2nd generation CB respectively. Patients profiles, periprocedural details and clinical events were recorded and compared between two cohorts. Results: Baseline characteristics were similar. 1st generation CB group showed more overall times of freeze per vein (1.8±1.0 vs 1.6±0.8, p＜0.01) and longer time-to-isolation in left superior pulmonary vein (91.0 ±49.1s vs 54.1±32.4 p=0.01). After three-years follow-up, the procedure complications had no difference between two groups. Through a mean follow-up period of 19.00±10.66 months, overall recurrence was comparable（62.4% vs 74.2%, p=0.13）and the survival analysis shows no difference either (Logrank P = 0.1807). The complications during follow-up showed no differences, including stroke events [3/133 vs 1/128, p=0.62], major hemorrhagic events [3/133 vs 1/128, p=0.62] and death of any cause [5/133 vs 2/128, p=0.25]. Conclusions: 1st and 2nd generation CBs are equally efficient and safe for PV ablation procedure and they are both suitable for Chinese population