Modification of atrioventricular conduction in dogs by laser irradiation of Koch’s triangle guided by balloon-tipped cardioscope

Abstract

This study assessed the feasibility of modification of atrioventricular (AV) conduction under direct vision with a new ablation system using laser energy. In 23 anesthetized dogs, a combined laser and balloon-tipped endoscope was introduced into the right atrium after right thoracotomy. Koch's triangle was easily identified in all dogs endoscopically. Nd:YAG laser energy was delivered through an optical fiber positioned inside the saline-filled balloon to the middle portion of Koch's triangle in eight dogs (mid-Koch group) and to the posterior portion in 12 dogs (postero-Koch group). Complete AV block was achieved in five of eight dogs in the mid-Koch group. In the postero-Koch group, anterograde Wenckebach cycle length increased significantly from 178+/-23 ms to 202+/-37 ms (P = 0.008). Selective laser ablation of Koch's triangle is feasible with a combined laser and balloon-tipped endoscope.