射频消融术中内部灌注与开放灌注在电极冷却方面对消融灶深度、血栓形成发生率及蒸汽泡的比较
Comparison of electrode cooling between internal and open irrigation in radiofrequency ablation lesion depth and incidence of thrombus and steam pop.
作者信息
Yokoyama Katsuaki, Nakagawa Hiroshi, Wittkampf Fred H M, Pitha Jan V, Lazzara Ralph, Jackman Warren M
机构信息
Cardiac Arrhythmia Research Institute, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
出版信息
Circulation. 2006 Jan 3;113(1):11-9. doi: 10.1161/CIRCULATIONAHA.105.540062. Epub 2005 Dec 27.
BACKGROUND
Electrode cooling by circulating fluid within the electrode (closed loop) or open irrigation facilitates radiofrequency (RF) ablation. This study compared lesion parameters between closed loop and open irrigation with the use of a canine model.
METHODS AND RESULTS
In 8 anesthetized dogs, the skin over the thigh muscle was incised and raised, forming a cradle superfused with heparinized blood (activated clotting time >350 seconds) at 37 degrees C. A 7F 4-mm closed loop electrode (irrigation 36 mL/min) and 7.5F 3.5-mm open irrigation electrode (irrigation 17 mL/min) were positioned perpendicular to the thigh muscle at 10 g contact weight. RF was applied (n=121) at 20 or 30 W for 60 seconds in low (0.1 m/s) or high (0.5 m/s) pulsatile blood flow. Temperatures were measured in the electrode, electrode-tissue interface, and within the tissue at 3- and 7-mm depths. After each RF, the cradle was emptied to examine the electrode and interface for thrombus. There was no difference between closed loop and open irrigation in impedance, lesion depth, or tissue temperature at 20 or 30 W. Interface temperature and electrode temperature were greater in the closed loop application. Thrombus occurred in 32 of 63 closed loop versus 0 of 58 open irrigation RF applications (P<0.05) with interface temperature > or =80 degrees C in all 32 (electrode temperature <40 degrees C in 1, 40 degrees C to 50 degrees C in 26, and >50 degrees C in 5). With closed loop, interface temperature and thrombus incidence were greater at 30 W and low blood flow. With open irrigation, interface temperature remained low (< or =71 degrees C) with no difference between 20 and 30 W or between low and high blood flow. Steam pop occurred at 20 W in 4 of 35 closed loop and 0 of 30 open irrigation and at 30 W in 15 of 28 closed loop and 4 of 28 open irrigation applications (P<0.05).
CONCLUSIONS
Lower interface temperature, thrombus, and steam pop, especially in low blood flow, indicate greater interface cooling with open irrigation.
背景
通过电极内循环流体（闭环）或开放式冲洗进行电极冷却有助于射频（RF）消融。本研究使用犬类模型比较了闭环和开放式冲洗之间的损伤参数。
方法与结果
在8只麻醉犬中，切开大腿肌肉上方的皮肤并掀起，形成一个在37℃下用肝素化血液（活化凝血时间>350秒）进行灌注的支架。将一个7F 4毫米的闭环电极（冲洗速度36毫升/分钟）和一个7.5F 3.5毫米的开放式冲洗电极（冲洗速度17毫升/分钟）以10克的接触重量垂直放置于大腿肌肉处。在低（0.1米/秒）或高（0.5米/秒）搏动血流状态下，以20或30瓦的功率施加RF 60秒（n = 121）。在电极、电极 - 组织界面以及组织内3毫米和7毫米深度处测量温度。每次RF施加后，排空支架以检查电极和界面是否有血栓形成。在20或30瓦时，闭环和开放式冲洗在阻抗、损伤深度或组织温度方面无差异。闭环应用时界面温度和电极温度更高。在63次闭环RF应用中有32次出现血栓，而58次开放式冲洗RF应用中无血栓形成（P<0.05），所有32次出现血栓的情况中界面温度≥80℃（电极温度1次<40℃，26次在40℃至50℃之间，5次>50℃）。对于闭环，在30瓦和低血流状态下界面温度和血栓发生率更高。对于开放式冲洗，界面温度保持较低（≤71℃），在20和30瓦之间或低血流和高血流之间无差异。在20瓦时，35次闭环中有4次出现蒸汽爆发现象，30次开放式冲洗中无；在30瓦时，28次闭环中有15次出现蒸汽爆发现象，28次开放式冲洗中有4次出现（P<0.05）。
结论
较低的界面温度、血栓形成和蒸汽爆发现象，尤其是在低血流状态下，表明开放式冲洗具有更好的界面冷却效果。
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