Electrophysiology Service, Department of Cardiology, Montreal Heart Institute, Université de Montréal, Montreal, Canada.
J Cardiovasc Electrophysiol. 2013 Jun;24(6):692-8. doi: 10.1111/jce.12114. Epub 2013 Mar 13.
Optimal cryoballoon ablation parameters for pulmonary vein (PV) isolation remain to be defined. We conducted a randomized preclinical trial to compare 2- versus 4-minute ablation lesions and assess the safety of active (forced) cryoballoon deflation.
Thirty-two dogs underwent PV isolation with a second-generation 23 mm cryoballoon catheter. The left superior (LSPV) and inferior (LIPV) PVs were randomized in a factorial design to (1) a single 2- versus 4-minute cryoapplication, and (2) passive versus active cryoballoon deflation. Animals were survived for 30 days, after which histopathologic analysis was performed. Acute PV isolation was attained in 89.8% of PVs after a single application (93.8% LSPV, 85.2% LIPV; P = 0.2823). Mean time to PV isolation was 29.5 ± 18.5 seconds. Although 4-minute lesions were associated with a thicker neointima than 2-minute lesions (223.8 μm versus 135.6 μm; P = 0.007), no differences were observed in procedural characteristics (freezing temperature, rewarming time), rates of acute PV isolation, or the achievement of complete circumferentially transmural lesions at 30 days (78.7% overall; 86.2% for 2 minutes vs 70.0% for 4 minutes; P = 0.285). Active deflation was associated with faster balloon rewarming but not with significant differences in mean or maximum neointimal thickness.
A single application with the second-generation cryoballoon catheter results in a high rate of PV isolation. The degree of vascular injury was not increased by active balloon deflation and no differences in acute efficacy or mature transmural circumferential lesions were observed with 2- versus 4-minute applications.
肺静脉（PV）隔离的最佳冷冻球囊消融参数仍有待确定。我们进行了一项随机的临床前试验，比较了 2 分钟与 4 分钟的消融损伤，并评估了主动（强制）冷冻球囊放气的安全性。
32 只狗接受了第二代 23mm 冷冻球囊导管的 PV 隔离。左肺上静脉（LSPV）和左肺下静脉（LIPV）按照两因素设计随机分为（1）单次 2 分钟与 4 分钟冷冻球囊应用，以及（2）被动与主动冷冻球囊放气。动物存活 30 天后进行组织病理学分析。单次应用后，89.8%的 PV 实现了急性 PV 隔离（93.8%的 LSPV，85.2%的 LIPV；P = 0.2823）。PV 隔离的平均时间为 29.5 ± 18.5 秒。虽然 4 分钟的损伤与较厚的新生内膜有关（223.8μm 与 135.6μm；P = 0.007），但在操作特性（冷冻温度、复温时间）、急性 PV 隔离率以及 30 天内实现完全环形透壁损伤方面没有差异（总发生率为 78.7%；2 分钟组为 86.2%，4 分钟组为 70.0%；P = 0.285）。主动放气与更快的球囊复温有关，但与平均或最大新生内膜厚度无显著差异。
第二代冷冻球囊导管单次应用可实现较高的 PV 隔离率。主动球囊放气并未增加血管损伤程度，与 2 分钟与 4 分钟应用相比，急性疗效或成熟的环形透壁损伤无差异。
