Langberg J J, Lee M A, Chin M C, Rosenqvist M
Department of Medicine, University of California, San Francisco 94143.
Pacing Clin Electrophysiol. 1990 Oct;13(10):1242-8. doi: 10.1111/j.1540-8159.1990.tb02022.x.
Radiofrequency current is a promising alternative to high voltage direct current defibrillator discharges for catheter ablation of arrhythmias. However, lesions produced with radiofrequency current are relatively small and use of high power is limited by the impedance rise that occurs with desiccation of tissue and coagulum formation. The effect of electrode size on radiofrequency ablation was assessed by comparing results of radiofrequency application using a standard 6 French electrode catheter (distal electrode 2 mm in length) to those using catheters modified with longer distal electrodes (3, 4, 6, 8, and 10 mm in length). Radiofrequency ablation was performed at 47 left ventricular endocardial sites in 20 anesthetized dogs. A constant power of 13.3 +/- 1.3 watts at 550 kHz was applied between the distal catheter electrode and a skin electrode until a total of 500 joules had been delivered or a rise in impedance occurred. Increasing electrode length from 2 to 4 mm more than doubled lesion volume from a mean of 143 to 326 mm3 (P = 0.025). Increasing electrode length beyond 4 mm produced progressively smaller lesions (157 mm3, 155 mm3, and 67 mm3 for 6-, 8-, and 10-mm electrode lengths, respectively). Impedance rise was significantly less likely with larger electrodes and took longer to occur. Increasing the size of electrodes used for radiofrequency ablation allows application of higher power without an impedance rise. Optimizing electrode size (3 or 4 mm in this study) results in larger lesions and may improve the effectiveness of radiofrequency ablation of arrhythmias.
对于心律失常的导管消融，射频电流是一种很有前景的替代高电压直流电除颤器放电的方法。然而，射频电流产生的损伤相对较小，并且高功率的使用受到组织干燥和凝块形成时阻抗升高的限制。通过比较使用标准6法国电极导管（远端电极长度为2毫米）与使用远端电极更长（长度分别为3、4、6、8和10毫米）的改良导管进行射频应用的结果，评估了电极尺寸对射频消融的影响。在20只麻醉犬的47个左心室心内膜部位进行了射频消融。在远端导管电极和皮肤电极之间施加550 kHz时13.3±1.3瓦的恒定功率，直到总共输送了500焦耳或出现阻抗升高。将电极长度从2毫米增加到4毫米，损伤体积从平均143立方毫米增加到326立方毫米以上（P = 0.025）。电极长度超过4毫米时，产生的损伤逐渐变小（6毫米、8毫米和10毫米电极长度对应的损伤体积分别为157立方毫米、155立方毫米和67立方毫米）。较大电极的阻抗升高明显不太可能发生，并且发生的时间更长。增加用于射频消融的电极尺寸可以在不出现阻抗升高的情况下应用更高的功率。优化电极尺寸（本研究中为3或4毫米）会导致更大的损伤，并可能提高心律失常射频消融的有效性。
