Wittkampf Fred H M, Nakagawa Hiroshi, Foresti Sarah, Aoyama Hiroshi, Jackman Warren M
Department of Cardiology, Heart Lung Center Utrecht, The Netherlands.
J Cardiovasc Electrophysiol. 2005 Mar;16(3):323-8. doi: 10.1046/j.1540-8167.2005.40629.x.
Open flush, irrigated ablation electrodes may improve the safety of radiofrequency catheter ablation by preventing protein aggregation and coagulum formation. This is particularly important in left-sided procedures like catheter ablation of atrial fibrillation. Electrode cooling and the inherent loss of temperature feedback, however, grossly reduce the ability to monitor tissue heating. Intimate contact may not be recognized and the delivery of nominal RF power levels may then lead to excessive tissue heating, steam explosions, and even tamponade.
Standard, open flush, irrigated catheters (Sprinklr, Medtronic Inc, Minneapolis, MN) were modified by thermally insulating the irrigation channels inside the ablation electrode. Using the thigh muscle preparation, multiple lesions were created with standard and modified catheters using 60 s, 20-50 Watt applications and a constant saline flush rate of 20 cc/min. A total of 57 lesions were created on five thigh muscles of three dogs. Lesion dimensions were not significantly different between both types of catheter, but the maximum electrode temperature rise during ablation was significantly higher with the modified catheter. Insulation of the irrigation channels improved the correlation coefficient between maximum electrode temperature rise and lesion volume from 0.38 (ns) to 0.62 (P < 0.001).
Thermal insulation of the irrigation channels facilitates temperature feedback during radiofrequency ablation and controllability of lesion formation.
开放式冲洗、灌注消融电极可通过防止蛋白质聚集和凝块形成来提高射频导管消融的安全性。这在诸如房颤导管消融等左侧手术中尤为重要。然而，电极冷却和温度反馈的固有损失极大地降低了监测组织加热的能力。可能无法识别紧密接触，此时标称射频功率水平的输送可能导致组织过度加热、蒸汽爆炸甚至心包填塞。
通过对消融电极内部的灌注通道进行隔热处理，对标准的开放式冲洗、灌注导管（Sprinklr，美敦力公司，明尼阿波利斯，明尼苏达州）进行了改良。使用大腿肌肉制备模型，使用标准导管和改良导管，以60秒、20 - 50瓦的功率施加以及20毫升/分钟的恒定盐水冲洗速率创建多个病变。在三只狗的五条大腿肌肉上共创建了57个病变。两种类型导管之间的病变尺寸无显著差异，但改良导管在消融期间的最大电极温度升高显著更高。灌注通道隔热处理将最大电极温度升高与病变体积之间的相关系数从0.38（无显著性差异）提高到了0.62（P < 0.001）。
灌注通道隔热处理有助于在射频消融期间进行温度反馈以及控制病变形成。
