Langberg J J, Gallagher M, Strickberger S A, Amirana O
Department of the Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0022.
Circulation. 1993 Jul;88(1):245-9. doi: 10.1161/01.cir.88.1.245.
Previous studies have shown that the size of lesions produced by radiofrequency catheter ablation correlates with the temperature and surface area of the electrode-tissue interface. The purpose of the present study was to compare the effects of ablation using very large distal electrodes (8F, 8 and 12 mm long) with those made by a conventional radiofrequency ablation catheter (distal electrode 8F, 4 mm long).
Each catheter had a thermistor in the tip of the distal electrode. Radiofrequency energy (500 kHz) was supplied by a generator that continuously monitored temperature and produced up to 100 W. In 10 dogs, each of the three ablation catheters were introduced percutaneously and positioned under fluoroscopic guidance at disparate left ventricular endocardial sites. Radiofrequency power output was titrated to achieve a temperature of 80 degrees C for 60 seconds at each ablation site. The power required to produce a steady-state temperature of 80 degrees C was directly proportional to electrode size (15 +/- 7, 46 +/- 15, and 62 +/- 32 W using the 4-mm-, 8-mm-, and 12-mm-long electrodes, respectively). Lesions produced by the 8-mm electrode were nearly twice as deep (11 +/- 2.4 versus 6 +/- 1.2 mm, P < .001) and four times as large (905 +/- 410 versus 210 +/- 100 mm3, P < .001) as those made with a conventional 4-mm electrode. Lesions produced by the 12-mm electrode were intermediate in size (depth, 8 +/- 1.2 mm; volume, 465 +/- 225 mm3) and sometimes were associated with charring and crater formation. Ablation with the larger electrodes caused a drop in arterial pressure and more ventricular ectopy than ablation using a 4-mm distal electrode.
Thermistor-equipped elongated ablation electrodes coupled to high-power outputs can reproducibly produce lesions approximately 1 cm in diameter. This system may prove useful for ablation of ventricular tachycardias in patients with coronary artery disease.
先前的研究表明，射频导管消融产生的损伤大小与电极-组织界面的温度和表面积相关。本研究的目的是比较使用非常大的远端电极（8F，8和12毫米长）与传统射频消融导管（远端电极8F，4毫米长）进行消融的效果。
每个导管在远端电极尖端都有一个热敏电阻。射频能量（500千赫）由一台连续监测温度并能产生高达100瓦功率的发生器提供。在10只狗身上，经皮插入三种消融导管中的每一种，并在透视引导下将其放置在不同的左心室心内膜部位。在每个消融部位将射频功率输出调整至在60秒内达到80摄氏度。产生80摄氏度稳态温度所需的功率与电极大小成正比（分别使用4毫米、8毫米和12毫米长的电极时，功率分别为15±7瓦、46±15瓦和62±32瓦）。8毫米电极产生的损伤深度几乎是传统4毫米电极的两倍（11±2.4毫米对6±1.2毫米，P<.001），大小是其四倍（905±410立方毫米对210±100立方毫米，P<.001）。12毫米电极产生的损伤大小居中（深度，8±1.2毫米；体积，465±225立方毫米），有时会伴有炭化和火山口形成。与使用4毫米远端电极进行消融相比，使用较大电极进行消融导致动脉压下降和室性早搏更多。
配备热敏电阻的细长消融电极与高功率输出相结合能够可重复地产生直径约1厘米的损伤。该系统可能对冠心病患者室性心动过速的消融有用。
