B-PO03-139 AN EVALUATION OF FUNCTIONAL MAPPING TECHNIQUES FOR AVNRT

Abstract

Identification of the correct ablation site for treatment of AV-nodal re-entrant tachycardia (AVNRT) has historically been determined by local electrogram appearance. We investigated whether activation mapping of the triangle of Koch improves identification of the correct ablation site for slow pathway modification. To determine if Ripple or isochronal activation mapping can accurately identify successful sites of slow pathway modification. We performed a retrospective analysis of all adult patients at our center who underwent an electrophysiology study and ablation with CARTO electroanatomic mapping for management of AVNRT from January 1, 2015 to October 31, 2019. Ripple (Biosense Webster) and isochronal mapping was applied to each map. The region of critical slowing was then identified on each map without knowledge of the successful ablation sites. We then measured the distance and orientation between the sites on the Ripple and isochronal maps with the successful ablation site. Sixty-seven patients underwent AVNRT ablation with CARTO, of which 18 cases had maps with sufficient point density for activation mapping. Mean age was 51y (20-76) with 72% typical AVNRT, 17% atypical, and 11% with dual features. All included cases used radiofrequency ablation as opposed to cryoablation. There were no episodes of complete heart block or acute damage to the AV node. The area of slowing on Ripple mapping was within an average of 5.7 mm (range 1.8-10.9, SD 2.5) of the successful ablation site, with 5 cases within 4 mm. Slowed conduction identified with isochronal mapping was on average 6.4 mm (range 2.7-12.5, SD 2.6) from the successful ablation site, with 5 cases within 4 mm. There was no statistical difference between the two methods (p-value = 0.51). There was no tendency towards any one direction for these measurements. Both Ripple and isochronal mapping accurately localized to the previously identified sites of successful ablation in the vast majority of cases, with a small range of error. There was no statistical difference between the accuracy of these two techniques. Prospective, multicenter trials are necessary to confirm whether activation mapping can enhance ablation in patients with AVNRT.