Background:The use of iodine contrast agents is one possible limitation in cryoballoon ablation (CBA) for atrial fibrillation (AF). This study investigated intracardiac echography (ICE)-guided contrast-free CBA.

Methods and Results:The study was divided into 2 phases. First, 25 paroxysmal AF patients (Group 1) underwent CBA, and peri-balloon leak flow velocity (PLFV) was assessed using ICE and electrical pulmonary vein (PV) lesion gaps were assessed by high-density electroanatomical mapping. Then, 24 patients (Group 2) underwent ICE-guided CBA and were compared with 25 patients who underwent conventional CBA (historical controls). In Group 1, there was a significant correlation between PLFV and electrical PV gap diameter (r=–0.715, P<0.001). PLFV was higher without than with an electrical gap (mean [±SD] 127.0±28.6 vs. 66.6±21.0 cm/s; P<0.001) and the cut-off value of PLFV to predict electrical isolation was 105.7 cm/s (sensitivity 0.700, specificity 0.929). In Group 2, ICE-guided CBA was successfully performed with acute electrical isolation of all PVs and without the need for “rescue” contrast injection. Atrial tachyarrhythmia recurrence at 6 months did not differ between ICE-guided and conventional CBA (3/24 [12.5%] vs. 5/25 [20.0%], respectively; P=0.973, log-rank test).

Conclusions:PLFV predicted the presence of an electrical PV gap after CBA. ICE-guided CBA was feasible and safe, and could potentially be performed completely contrast-free without a decrease in ablation efficacy.

背景：碘造影剂的使用是心房颤动 (AF) 冷冻球囊消融 (CBA) 的一种可能限制。本研究调查了心内超声 (ICE) 引导的无造影剂 CBA。

方法和结果：该研究分为2个阶段。首先，25 名阵发性 AF 患者（第 1 组）接受 CBA，并使用 ICE 评估球囊周围泄漏流速（PLFV），并通过高密度电解剖标测评估电肺静脉（PV）病变间隙。然后，24 名患者（第 2 组）接受了 ICE 引导的 CBA，并与 25 名接受常规 CBA 的患者（历史对照）进行了比较。在第 1 组中，PLFV 与电 PV 间隙直径之间存在显着相关性（r=–0.715，P<0.001）。PLFV 在没有电气间隙的情况下高于没有电气间隙的情况（平均 [±SD] 127.0±28.6 vs. 66.6±21.0 cm/s; P<0.001），PLFV 预测电气隔离的截止值为 105.7 cm/s（灵敏度0.700，特异性 0.929）。在第 2 组中，ICE 引导的 CBA 成功地执行了所有 PV 的急性电隔离，并且无需“救援”造影剂注射。6 个月时房性快速心律失常复发在 ICE 引导和常规 CBA 之间没有差异（分别为 3/24 [12.5%] 和 5/25 [20.0%]；P=0.973，对数秩检验）。

结论： PLFV 预测 CBA 后电 PV 间隙的存在。ICE 引导的 CBA 是可行且安全的，并且可能在不降低消融效果的情况下完全无造影剂进行。