Nonuniform heating during radiofrequency catheter ablation with long electrodes: monitoring the edge effect.
Nonuniform heating during radiofrequency catheter ablation with long electrodes: monitoring the edge effect.
复制标题
使用长电极进行射频导管消融期间的不均匀加热：监测边缘效应。
DOI：
10.1161/01.cir.96.11.4057
复制
发表时间：
1997
期刊：
影响因子：
37.8
通讯作者：
D. E. Haines
中科院分区：
文献类型：
--
作者：
I. McRury;Dorin Panescu;Mark A. Mitchell;D. E. Haines
背景
长而窄的电极正在考虑用于心房颤动的射频消融；然而，初步工作显示电极上形成凝块并且缺乏病变连续性。这可能是由于“边缘效应”，它将辐射能量集中在尖锐的几何梯度上。建议在温度反馈和长电极几何形状监测方面，电极边缘的温度传感器优于单个中心传感器。
方法和结果
有限元模型用于预测新型长电极几何形状的加热特性。使用带有多个 12.5 毫米线圈电极的导管对 16 只患有心房颤动的狗进行左心房和右心房消融术。将具有单个热敏电阻的电极与具有放置在电极的相对端和相对侧的双热电偶的电极进行比较。记录所有损伤的功率、温度和阻抗，并记录损伤子集中的凝块粘附和强度。有限元分析显示加热不均匀，主要加热集中在电极边缘，并且在单热敏电阻反馈控制下温度倾向于 >100 摄氏度。与使用单热敏电阻电极的消融相比，使用双热电偶电极的消融以较低的功率水平实现了更高的测量温度。双热电偶电极比单中心热敏电阻电极出现阻抗升高和凝块粘附的频率较低（分别为 395 个病变中的 176 个与 425 个病变中的 9 个；P<.0001；98 个病变中的 46 个与 150 个病变中的 7 个；P<.0001）。
结论
射频能量产生的最大热量发生在电极边缘，尤其是长电极。通过监测边缘温度，可以显着提高使用这些电极进行温度反馈心房消融的安全性。
BACKGROUND
Long, narrow electrodes are being considered for radiofrequency ablation of atrial fibrillation; however, preliminary work revealed coagulum formation on the electrodes and lack of lesion continuity. This may be due to the "edge effect," which concentrates radiated energy at sharp geometric gradients. It is proposed that temperature sensors at electrode edges are preferable to a single centered sensor for temperature feedback and monitoring of long electrode geometries.
METHODS AND RESULTS
A finite element model was used to predict the heating properties of new long electrode geometries. Sixteen dogs with atrial fibrillation underwent left and right atrial ablation using catheters with multiple 12.5-mm coil electrodes. Electrodes with a single thermistor were compared with electrodes with dual thermocouples placed at opposite ends and on opposing sides of the electrode. Power, temperature, and impedance were recorded for all lesions, and coagulum adhesion and magnitude were noted in a subset of lesions. Finite element analysis shows uneven heating, with the main heating concentrated at the electrode edges and a propensity toward temperatures >100 degrees C with single-thermistor feedback control. Ablations with dual thermocouple electrodes achieved higher measured temperatures at lower power levels than those that used single-thermistor electrodes. Impedance rises and coagulum adherence occurred less frequently with dual thermocouple electrodes than with single, centered thermistor electrodes (176 of 395 versus 9 of 425 lesions; P<.0001; 46 of 98 versus 7 of 150 lesions; P<.0001, respectively).
CONCLUSIONS
Maximum heating from radiofrequency energy occurs at the electrode edges, particularly with long electrodes. The safety of temperature-feedback atrial ablation with these electrodes is significantly improved by monitoring temperatures at the edges.