247 Propagation Mapping (PM) in Atrioventricular Nodal Reentry Tachycardia to Identify Wave Collision (WC) and Its Proximity to Successful site of Ablation

Abstract

Voltage mapping is an important guide in slow-pathway ablation for AVNRT. PM of a collision wave front within the triangle of Koch (TK) has been described in children to optimise slow pathway localisation. Blinded assessment of PM in an adult AVNRT population. We evaluated PM in patients who underwent voltage guided AVNRT ablation. Patients had (Ensite 3D NAVX; Abbott) guided voltage maps performed, then reevaluated with PM offline. Atrial propagation evaluation during sinus rhythm (SR) was used to identify the wave collision (WC) site. Intersection of the two wave fronts within TK was identified. The proximity of WC to successful site of ablation was evaluated in a blind fashion. Analysis of the distance between the successful ablation site (AS) and site of WC, measured as the distance from the AS centre identified as a 3D lesion to the nearest WC point. 23 patients (39% male) were 45±19 yrs. PM mapping was feasibile in 100%, as during SR, WC was identified on PM in all patients. Atrial signals conducted in a line from mid-CS in 74% of patients in both a superior-to-inferior and inferior-to-superior pattern and collide in the mid TK. Mean absolute distance between WC and ablation site was 3.7±3.9mm. Inter-observer (n=20; 2nd observer identifying site of WC) analysis found mean differences (absolute, relative) of 0.6±0.6mm, 17±24% respectively. PM demonstrates WC close to the successful ablation site. A prospective trial of the role of propagation mapping in AVNRT is needed.