Curtis A B, Mansour M, Friedl S E, Tomaru T, Barbeau G R, Normann S J, Abela G S
Department of Medicine, University of Florida, Gainesville 32610.
Pacing Clin Electrophysiol. 1994 Mar;17(3 Pt 1):337-48. doi: 10.1111/j.1540-8159.1994.tb01396.x.
Ablation of the AV junction is an accepted technique for the management of selected supraventricular tachyarrhythmias. Radiofrequency ablation appears to be safe and effective for AV junction ablation in most patients, but the need for firm tissue contact may make it less effective for ventricular tachycardia and certain ectopic/atrial tachycardias. Laser energy can also be delivered through a catheter, and thus it may be an attractive alternative energy source for ablation. A new laser-electrode catheter was developed for modification of conduction through the AV node as a model for ablation of an arrhythmia substrate. A window for delivery of continuous-wave Nd:YAG laser energy was placed between the two electrodes of a bipolar electrode catheter. In vitro studies using a matrix of power versus time were performed to determine the energy that would create lesions of the appropriate size in vivo. Using this information, advanced AV block was successfully created in 16 of 17 dogs (94%) with the laser-electrode catheter. Advanced AV block was successfully created in all four dogs in the chronic study, and it persisted for 1-24 weeks of follow-up until sacrifice of the animals. Histologic examination demonstrated discrete thermal damage at the AV junction with no instances of septal perforation in the acute studies or progressive necrosis in chronically maintained dogs. Advanced AV block may be produced consistently and safely in dogs using a combined laser-electrode catheter.
房室结消融是治疗特定室上性快速心律失常的一种公认技术。对于大多数患者，射频消融用于房室结消融似乎安全有效，但由于需要紧密的组织接触，对于室性心动过速和某些异位/房性心动过速可能效果较差。激光能量也可通过导管传递，因此它可能是一种有吸引力的替代消融能量源。为了通过改变房室结传导作为心律失常基质消融的模型，研发了一种新型激光电极导管。在双极电极导管的两个电极之间设置了一个用于传输连续波钕：钇铝石榴石激光能量的窗口。进行了功率与时间矩阵的体外研究，以确定在体内能产生适当大小损伤的能量。利用这些信息，使用激光电极导管在17只犬中的16只（94%）成功造成了高度房室传导阻滞。在慢性研究的所有4只犬中均成功造成了高度房室传导阻滞，并且在后续1至24周的随访中一直持续，直至处死动物。组织学检查显示，在急性研究中房室结处有离散的热损伤，未出现间隔穿孔情况；在长期维持的犬中也未出现进行性坏死。使用联合激光电极导管可在犬中持续且安全地产生高度房室传导阻滞。
