抄録
Recently, a surgical procedure has been employed for treatment of ventricular tachycardia, that paroxysmal supraventricular tachycardia due to atrio-ventricular (A-V) nodal reentry is refractry to medical therapy. We have studied for inducing the complete A-V block with application of Argon-laser and Nd-YAG laser without extracorporeal circulation.[Methods]Twenty mongorel dogs were used in this study. Under general anesthesia, the laser-probe was guided to the A-V node from their right auricule, with monitoring electrogram of His bundle. Laser power was set up from 6W to 10W, and the time of ablation between 3 and 5 secs. Therafter, the laser-ablation was initiated, and its hemodinamics were observed and recorded.[Results]The complete A-V block was produced in all dogs. Total laser energy for inducing of the complete A-V block by Nd-YAG-laser was in average of 68.2 J. And, in case of Argon-laser it was 224 J in average. In this study it could be recognized that, Nd-YAG-laser reached more deeper region of myocardium than that of Argon-laser. The histological findings at the site of the endocardium induced by laser ablation showed the coaglation necrosis with vacuolization, and the borderline between the coagulation necrosis and the native myocardium was completely demarcated.
[Conclusions]1) The complete A-V block could be easily achieved by laser ablation without extracorporeal circulation. 2) Nd-YAG-laser was more effect to induce the complete A-V block than Argon-laser.
