Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan.
Royal Papworth Hospital, Cambridge University, Cambridge, UK.
J Cardiovasc Electrophysiol. 2023 Aug;34(8):1671-1680. doi: 10.1111/jce.15964. Epub 2023 Jun 19.
Little is known about the impact of blood-pool local impedance (LI) on lesion characteristics and the incidence of steam pops.
Radiofrequency applications at a range of powers (30, 40, and 50 W), contact forces (CF) (5, 15, and 25 g), and durations (15, 30, 45, and 120 s) using perpendicular/parallel catheter orientation were performed in 40 excised porcine preparations, using a catheter capable of monitoring LI (StablePoint©, Boston Scientific). To simulate the variability in blood-pool impedance, the saline-pool LI was modulated by calibrating saline concentrations. Lesion characteristics were compared under three values of saline-pool LI: 120, 160, and 200 Ω.
Of 648 lesions created, steam pops occurred in 175 (27.0%). When power, CF, time, and catheter orientation were adjusted, ablation at a saline-pool impedance of 160 or 200 Ω more than doubled the risk of steam pops compared with a saline-pool impedance of 120 Ω (Odds ratio = 2.31; p = .0002). Lesions in a saline-pool impedance of 120 Ω were significantly larger in surface area (50 [38-62], 45 [34-56], and 41 [34-60] mm for 120, 160, and 200 Ω, p < .05), but shallower in depth (4.0 [3-5], 4.4 [3.2-5.3], and 4.5 [3.8-5.5] mmfor 120, 160, and 200 Ω, respectively, p < .05) compared with the other two settings. The correlation between the absolute LI-drop and lesion size weakened as the saline-pool LI became higher (e.g., 120 Ω group (r = .30, r = .18, and r = .16, respectively for 120, 160, and 200 Ω), but the usage of %LI-drop (= absolute LI-drop/initial LI) instead of absolute LI-drop may minimize this effect.
In an experimental model, baseline saline-pool impedance significantly affects the lesion metrics and the risk of steam pops.
关于血池局部阻抗（LI）对病变特征和蒸汽 pops 发生率的影响知之甚少。
使用可监测 LI（StablePoint©，Boston Scientific）的导管，在 40 个离体猪制剂中进行功率（30、40 和 50W）、接触力（CF）（5、15 和 25g）和持续时间（15、30、45 和 120s）范围的射频应用，采用垂直/平行导管方向。为了模拟血池阻抗的可变性，通过校准盐水浓度来调制盐水池 LI。在三种盐水池 LI 值（120、160 和 200Ω）下比较病变特征。
在创建的 648 个病变中，发生了 175 个蒸汽 pops（27.0%）。当调整功率、CF、时间和导管方向时，与 120Ω盐水池阻抗相比，160 或 200Ω盐水池阻抗的消融使蒸汽 pops 的风险增加了一倍以上（优势比=2.31；p=0.0002）。在 120Ω盐水池阻抗下，病变的面积明显更大（50[38-62]、45[34-56]和 41[34-60]mm 分别为 120、160 和 200Ω，p<0.05），但深度较浅（4.0[3-5]、4.4[3.2-5.3]和 4.5[3.8-5.5]mm 分别为 120、160 和 200Ω，p<0.05）与其他两个设置相比。随着盐水池 LI 的升高，绝对 LI 下降与病变大小之间的相关性减弱（例如，在 120Ω 组中（r=0.30、r=0.18 和 r=0.16，分别为 120、160 和 200Ω），但使用 %LI 下降（=绝对 LI 下降/初始 LI）代替绝对 LI 下降可能会最小化这种影响。
在实验模型中，基础盐水池阻抗显着影响病变指标和蒸汽 pops 的风险。
