Frohner K J, Podczeck A, Hief C, Nurnberg M, Steinbach K K
Department of Cardiology, Wilhelminen Hospital, Vienna, Austria.
Pacing Clin Electrophysiol. 1990 Jun;13(6):719-23. doi: 10.1111/j.1540-8159.1990.tb02097.x.
Radiofrequency ablation of the atrioventricular conduction system was attempted in a 63-year-old man with drug refractory atrial fibrillation. A total of 5 radiofrequency pulses (750 kHz, power setting: 25-50 W, pulse duration: 9-20 sec) were delivered in a unipolar fashion via the distal electrode of a 7 Fr bipolar electrode catheter without induction of permanent AV block. No direct measurements of current (I) and voltage (U) were made. During the fifth pulse catheter disruption occurred at the interface of the shaft and the proximal electrode. Inspection of the catheter shaft revealed carbonized insulation material indicating overheating of the catheter tip. Overheating was presumably due to an impedance rise with unrecognized clot formation on the distal electrode. This led to progressive melting of insulation material during repeated radiofrequency applications and short circuiting of current flow to the proximal ring electrode that resulted in catheter disruption. This case report is the first to describe a serious complication of radiofrequency ablation. The complication might have been prevented by measurements of U and I, reflecting changes in impedance or by measurements of catheter tip temperature (T). It is concluded that measurements of U, I, and/or T are necessary to control the coagulation process thereby reducing the risk of serious complications during transcatheter radiofrequency ablation.
对一名63岁药物难治性心房颤动男性患者尝试进行房室传导系统的射频消融。通过一根7F双极电极导管的远端电极以单极方式总共输送了5个射频脉冲（750kHz，功率设置：25 - 50W，脉冲持续时间：9 - 20秒），未诱发永久性房室传导阻滞。未进行电流（I）和电压（U）的直接测量。在第五个脉冲期间，导管在杆身与近端电极的交界处发生断裂。检查导管杆身发现绝缘材料碳化，提示导管尖端过热。过热可能是由于远端电极上形成未被识别的血栓导致阻抗升高。这导致在重复进行射频应用期间绝缘材料逐渐熔化，电流流向近端环形电极短路，从而导致导管断裂。本病例报告首次描述了射频消融的一种严重并发症。通过测量反映阻抗变化的U和I或通过测量导管尖端温度（T），这种并发症可能得以预防。得出结论，测量U、I和/或T对于控制凝固过程是必要的，从而降低经导管射频消融期间严重并发症的风险。
