Reithmann Christopher, Remp Thomas, Hoffmann Ellen, Matis Tomas, Wakili Reza, Steinbeck Gerhard
Medizinische Klinik I, Klinikum Grosshadern, Universität München, München, Germany.
Pacing Clin Electrophysiol. 2005 Dec;28(12):1282-91. doi: 10.1111/j.1540-8159.2005.00269.x.
A variety of strategies have been proposed to avoid the risks of pulmonary vein ablation for atrial fibrillation. The fall of impedance during radiofrequency catheter ablation can be used as a real time measure of tissue heating. The aim of this study was to analyze the impedance fall during ostial pulmonary vein ablation and to evaluate whether adjusting power to the fall of impedance may contribute to a reduction of the risk of complications.
Analysis of biophysical parameters of ablation and determination of ostial diameters during follow-up were performed in 70 patients undergoing impedance-guided segmental ostial pulmonary vein ablation. Repeat radiographic angiography, local electrograms, and baseline impedance were the criteria to define the position of the 4-mm electrode tip at atrial sites or inside the proximal pulmonary veins.
Energy application inside the proximal pulmonary veins led to an increased impedance fall inside the first 5-10 mm of the pulmonary veins (1.1 +/- 0.5 Omega/W) as compared to ablation at atrial sites (0.7 +/- 0.3 Omega/W) (P < 0.01). The analysis of temperature and impedance fall during ostial ablation demonstrated an increased impedance fall with heating at sites inside the proximal pulmonary veins (1.5 +/- 0.6 Omega/ degrees C) as compared to atrial sites (1.2 +/- 0.5 Omega/ degrees C) (P < 0.001). The regression lines analyzing these correlations indicated that adjusting power to a maximum impedance fall of 20 Omega would limit heating at pulmonary venous sites to lower temperatures (average maximum temperature: 48 degrees C) than at atrial sites (average maximum temperature: 63 degrees C). The ablation strategy used for segmental ostial ablation in 70 patients, which involved power limitation to a maximum impedance fall of 20 Omega, allowed isolation of 89% of targeted pulmonary veins with a low rate of impedance rises (0.3% of applications). No pulmonary vein stenoses >30% were detected by follow-up computed tomography analysis.
An increased impedance fall as the result of heating during ostial ablation was found inside the proximal pulmonary veins as compared to atrial sites. Adjusting power to the fall of impedance during segmental ostial pulmonary vein ablation contributes to the prevention of overheating inside the pulmonary veins and may lower the risk of coagulum formation and pulmonary vein stenosis.
已提出多种策略来规避心房颤动肺静脉消融的风险。射频导管消融期间阻抗的下降可作为组织加热的实时测量指标。本研究的目的是分析肺静脉口部消融期间的阻抗下降情况，并评估根据阻抗下降调整功率是否有助于降低并发症风险。
对70例行阻抗引导下节段性肺静脉口部消融的患者进行消融生物物理参数分析及随访期间口部直径测定。重复血管造影、局部电图和基线阻抗是确定4毫米电极尖端在心房部位或肺静脉近端内部位置的标准。
与在心房部位消融相比，在肺静脉近端内部施加能量导致肺静脉前5 - 10毫米内的阻抗下降增加（1.1±0.5Ω/W），而在心房部位为（0.7±0.3Ω/W）（P < 0.01）。口部消融期间温度和阻抗下降分析表明，与心房部位（1.2±0.5Ω/℃）相比，肺静脉近端内部部位加热时阻抗下降增加（1.5±0.6Ω/℃）（P < 0.001）。分析这些相关性的回归线表明，将功率调整至最大阻抗下降20Ω会将肺静脉部位的加热限制在比心房部位更低的温度（平均最高温度：48℃）（平均最高温度：63℃）。用于70例患者节段性肺静脉口部消融的消融策略，即将功率限制在最大阻抗下降20Ω，可隔离89%的目标肺静脉，阻抗上升率较低（0.3%的应用）。随访计算机断层扫描分析未检测到>30%的肺静脉狭窄。
与心房部位相比，在肺静脉口部消融期间加热导致肺静脉近端内部的阻抗下降增加。在节段性肺静脉口部消融期间根据阻抗下降调整功率有助于预防肺静脉内部过热，并可能降低血栓形成和肺静脉狭窄的风险。
