OPTIMAL TEMPERATURE AND ACUTE EFFECT ON SINUS NODE OF ABLATION AT JUNCTION BETWEEN SUPERIORVENA CAVA AND RIGHT ATRIUM;ELECTROPHYSIOLOGICAL AND HISTOLOGICALEVALUATION USING OUR THERMAL BALLOON CATHETER

摘要

We sought to determine the optimal temperature for the electrical isolation (El) between the superior vena cava (SVC) and the right atrium (RA) of 10 pigs by radiofrequency catheter ablation (RFA) and to histologically and electrophysiologically evaluate an acute thermal effect on the sinus node (SN) by RFA using our original thermal balloon catheter (TBC). Group-1 (#1-5) belonged to the initial ablative temperature at <55(deg)C, and group-2 at >55(deg)C (#6-10), The setting of the temperature was carried out in a step-up of 2-5(deg)C until the elimination of the SVC potentials (SVCPs) or occurrence of sinus arrest >2sec (endpoint). Successful El was achieved in all cases. Group-1 necessitated more Sequent attempts of the energy delivery than group-2 (2.8+-0.4 vs. 1.2+-0.4; p=0.0005). Moreover, a new atrial tachycardia associated with the conduction delay between the SVC and the RA was induced in 3 cases of the group-1 after the ablation at <55(deg)C. Contrariwise, sinus arrest had appeared in one case of each group during the ablation at 60(deg)C. Although there was no difference between before and after the ablation in corrected SN recovery time, the heat injury in the SN was histologically certified. The optimal temperature for the El is considered approximately 55(deg)C.