Section of Cardiac Electrophysiology, Division of Cardiology, University of Colorado, Aurora, Colorado.
Section of Cardiac Electrophysiology, Division of Cardiology, University of Colorado, Aurora, Colorado.
JACC Clin Electrophysiol. 2018 Apr;4(4):491-500. doi: 10.1016/j.jacep.2017.10.003. Epub 2017 Nov 29.
Given a paucity of data, the aim of this study was to define predictors of steam pops (SPs) during open-irrigated radiofrequency ablation (RFA).
SPs during RFA can lead to dire consequences, including perforation and stroke.
In an ex vivo bovine myocardium model, open-irrigated RFA was applied at 50 W for 60 s; intracardiac echocardiographic images for RFA with and without SPs was compared. Using an in vivo porcine model, open-irrigated RFA was applied at 50 W for 60 s, and RFA parameters of SPs were analyzed. A retrospective analysis was performed of recorded SPs during clinical ablation procedures over a 1-year period.
For RFA SPs, there was 32% greater intracardiac echocardiographic tissue echogenicity than for RFA without SPs (p < 0.001). In addition, RFA SPs had more rapid increases of tissue echogenicity, particularly in the last 5 s before SPs. Compared with RFA without SPs, RFA SPs had larger impedance reductions (33.0 ± 16.0 Ω vs. 23.0 ± 10.8 Ω; p = 0.032). SPs were also associated with more rapid initial impedance reduction (1.40 Ω/s vs. 0.38 Ω/s for RFA without SPs; p = 0.001). Clinical SPs during ablation procedures had a significantly faster impedance reduction during the first 5 s of ablation compared with matched control ablations (15.7 ± 6.7 Ω vs. 8.1 ± 4.7 Ω; p < 0.0001).
Certain echocardiographic and biophysical parameters during open-irrigated RFA are associated with increased SP risks. These include greater tissue echogenicity, larger total impedance reduction, rapid rate of initial impedance reduction, and rapid increase in tissue echogenicity.
鉴于数据匮乏，本研究旨在确定开放式射频消融（RFA）过程中出现蒸汽 pops（SPs）的预测因素。
RFA 过程中出现 SPs 可能导致严重后果，包括穿孔和中风。
在牛离体心肌模型中，以 50 W 行 60 s 的开放式射频消融；对比有和无 SPs 时的 RFA 心内超声图像。在猪的体内模型中，以 50 W 行 60 s 的开放式射频消融，分析 SPs 的 RFA 参数。对一年内记录的临床消融过程中的 SPs 进行回顾性分析。
与无 SPs 的 RFA 相比，SPs 时心内超声组织回声增强 32%（p < 0.001）。此外，SPs 时 RFA 组织回声增强更快，尤其是在 SPs 出现前的最后 5 s。与无 SPs 的 RFA 相比，SPs 时阻抗降低幅度更大（33.0 ± 16.0 Ω vs. 23.0 ± 10.8 Ω；p = 0.032）。SPs 时阻抗的初始降低也更快（1.40 Ω/s 比无 SPs 的 RFA 时的 0.38 Ω/s；p = 0.001）。与匹配的对照消融相比，消融过程中临床 SPs 时的阻抗在消融的前 5 s 内降低速度明显更快（15.7 ± 6.7 Ω vs. 8.1 ± 4.7 Ω；p < 0.0001）。
在开放式射频消融过程中，某些超声心动图和生物物理参数与 SPs 风险增加相关，包括组织回声增强程度更大、总阻抗降低幅度更大、初始阻抗降低速度更快、组织回声增强速度更快。
