Dorwarth Uwe, Fiek Michael, Remp Thomas, Reithmann Cristopher, Dugas Martin, Steinbeck Gerhard, Hoffmann Ellen
Medizinische Klinik I, Klinikum Grosshadern, Muenchen, Germany.
Pacing Clin Electrophysiol. 2003 Jul;26(7 Pt 1):1438-45. doi: 10.1046/j.1460-9592.2003.t01-1-00208.x.
The success and safety of standard catheter radiofrequency ablation may be limited for ablation of atrial fibrillation and ventricular tachycardia. The aim of this study was to characterize and compare different cooled and noncooled catheter systems in terms of their specific lesion geometry, incidence of impedance rise, and crater and coagulum formation to facilitate appropriate catheter selection for special indications. The study investigated myocardial lesion generation of three cooled catheter systems (7 Fr, 4-mm tip): two saline irrigation catheters with a showerhead-type electrode tip (sprinkler) and a porous metal tip and an internally cooled catheter. Noncooled catheters (7 Fr) had a large tip electrode (8 mm) and a standard tip electrode (4 mm). RF energy was delivered on isolated porcine myocardium superfused with heparinized pig blood (37 degrees C) at power settings of 10-40 W. Both irrigated systems were characterized by a large lesion depth (8.1 +/- 1.6 mm) and a large lesion diameter (13.8 +/- 1.6 mm). In comparison, internally cooled lesions showed a similar lesion depth (8.0 +/- 1.0 mm), but a significantly smaller lesion diameter (12.3 +/- 1.2 mm,P = 0.04). Large tip lesions had a similar lesion diameter (14.5 +/- 1.6 mm), but a significantly smaller lesion depth (6.3 +/- 1.0 mm,P = 0.002) compared to irrigated lesions. However, lesion volume was not significantly different between the three cooled and the large tip catheter. To induce maximum lesion size, power requirements were three times higher for the irrigation systems and two times higher for the internally cooled and the large tip catheter compared to the standard catheter. Impedance rise was rarest with irrigated and large tip ablation. In case of impedance rise crater formation was a frequent observation (61-93%). Irrigated catheters prevented coagulum formation most effectively. Irrigated rather than internally cooled ablation appears to be most adequate for the induction of deep and long lesions at a low rate of impedance rise and thrombus formation. Large tip ablation may be feasible for the creation of long linear lesions, however, with an increased risk of thrombus formation.
标准导管射频消融治疗心房颤动和室性心动过速的成功率及安全性可能存在一定局限。本研究旨在对不同的冷却式和非冷却式导管系统进行特性分析和比较，内容包括其特定的损伤几何形状、阻抗升高发生率以及火山口和凝块形成情况，以便为特殊适应证选择合适的导管。该研究调查了三种冷却式导管系统（7F，4mm尖端）产生心肌损伤的情况：两种带有喷头型电极尖端（喷淋头）和多孔金属尖端的盐水灌注导管以及一种内部冷却导管。非冷却式导管（7F）有一个大的尖端电极（8mm）和一个标准尖端电极（4mm）。在功率设置为10 - 40W的情况下，将射频能量施加于用肝素化猪血（37℃）灌注的离体猪心肌上。两种灌注系统的特点是损伤深度大（8.1±1.6mm）且损伤直径大（13.8±1.6mm）。相比之下，内部冷却损伤的深度相似（8.0±1.0mm），但损伤直径明显较小（12.3±1.2mm，P = 0.04）。与灌注损伤相比，大尖端损伤的直径相似（14.5±1.6mm），但损伤深度明显较小（6.3±1.0mm，P = 0.002）。然而，三种冷却式导管和大尖端导管之间的损伤体积并无显著差异。为诱导最大损伤尺寸，与标准导管相比，灌注系统的功率需求高出三倍，内部冷却导管和大尖端导管的功率需求高出两倍。灌注消融和大尖端消融时阻抗升高最为罕见。在出现阻抗升高的情况下，经常观察到火山口形成（61 - 93%）。灌注导管最有效地防止了凝块形成。与内部冷却消融相比，灌注消融似乎最适合以低阻抗升高率和血栓形成率诱导深而长的损伤。大尖端消融对于创建长线性损伤可能是可行的，然而，血栓形成风险会增加。
