Abstract 19861: Spatial Thermodynamics and Characteristics of Cavo-Tricuspid Isthmus and Mitral Isthmus Lesions Created by a Novel Cryo Linear Ablation Catheter in a Canine in Vivo Model

Introduction: Cryo energy balloon catheters have been widely accepted as a tool for isolation of the pulmonary veins. However, mitral annulus and tricuspid annulus have never been assessed for cryo ablation. This study was conducted to investigate spatial thermodynamics and lesions created by a newly developed linear cryo energy ablation catheter. Methods: Fourteen normal dogs underwent catheter ablation using a novel cryo linear ablation catheter which has cooling elements and a length of 35mm. Cryo ablation for cavo-tricuspid isthmus (CTI) and the mitral isthmus (MI) were performed using deliveries of 180 sec and 300 sec freeze. Catheter position was assessed by intracardiac ultrasound (ICE). The tissue temperature was monitored during cryo ablation using thermocouples implanted to the epicardium of the ablation site. Gross and microscopic pathologic characteristics of the lesions were examined. Results: The lesion characteristics was not different between 180 and 300sec freezes (Table), however, the gap sites were consistent with poor catheter contact on ICE. The lowest temperature of a site, located 10mm 35.3±1.3 °C (30.4 to 36.7 °C) (Figure). Three collateral lesions in right lungs, where just next to CTI region, were observed. Conclusions: This study showed feasibility to create continuous, transmural lesions for CTI, and MI ablation using this novel cryo catheter. ICE imaging is helpful to achieve lesion transmurality and continuity. The safety margin for ablation should be about 10mm to avoid collateral damage.