Spatiotemporal dispersion characterization in persistent and long-standing persistent atrial fibrillation patients, insights from the TAILORED-AF trial

Abstract Background/Introduction The TAILORED-AF trial (NCT04702451) was the first randomized, superiority trial demonstrating that artificial intelligence (AI)-guided ablation of persistent atrial fibrillation (AF) patients targeting spatiotemporal dispersion in addition to pulmonary vein isolation (PVI) is superior to PVI alone after one year of follow-up. Purpose This TAILORED-AF sub-analysis aims to characterize spatiotemporal dispersion regions in relation to atrial regions where AF terminated during an AI-guided tailored ablation procedure. Methods Spatiotemporal dispersion maps were built during index ablation procedures with an artificial intelligence-guided spatiotemporal dispersion software. Dispersion atrial extent was defined as the ratio of dispersion surface area in a chamber over its total chamber surface area quantified with an in-house algorithm. The algorithm estimates pixel surface area values from 2D snapshots collected from 3D navigation maps. After (i) conversion of antero-posterior and postero-anterior 2D view snapshots into grayscale-transformed images, (ii) the background was removed and the atria were segmented. Then, (iii) tags were detected, segmented and (iv) connected to remnant regions. Finally, spatiotemporal dispersion region locations and extent were superimposed with tags corresponding to AF termination locations in patients in whom AF was terminated. This corresponded to a location where AF terminated by ablation into sinus rhythm/atrial tachycardia or where the AF cycle length increased by a minimum of 20ms. Results The Tailored arm population included 187 persistent and long-standing persistent AF patients. The dispersion extent was higher in the left atrium (LA) compared to the right atrium (RA) (14.7% [8.1%-24.5%] vs 0.6% [0.0%-2.5%], p<0.0001). All patients (100%) had dispersion in the LA, whereas dispersion was only detected in the RA in 79% of the patients. The most frequent regions in LA exhibiting dispersion were the LA posterior wall with 20% [8%-31%] extent, LA anterior wall with 15% [8%-25%] extent and the LA roof with 10% [4%-19%] extent. The acute AF termination rate was 66%. All AF termination locations (100%) were found within dispersion regions: 25% in the lower quartile dispersion extent, 26% in the medium quartile and 49% in the higher quartile. In 81% of the patients, AF termination occurred in the LA, from which 20% located in the PV region and 80% outside the PV region. AF terminated in the RA in 19% of the patients (Figure). Conclusion(s) While pursuing an AI-guided ablation of persistent atrial fibrillation, spatiotemporal dispersion and AF termination predominantly occurs in the left atrium. Still, 19% of termination is observed after ablation in minimally extended regions of the RA. These findings highlight the importance of mapping and ablating in the RA when conducting a spatiotemporal dispersion-based ablation.