P991Pattern of rapid activity is preserved in persistent AF in selected locations after pulmonary vein isolation

Abstract Funding Acknowledgements Our research group receives an educational grant from Abbott Inc. Introduction. There is evidence to suggest that structural remodelling in psAF potentially gives rise to areas of rapid cycle length activity that may act as driving mechanisms. We describe a new method to compare rapid activity (RA) in psAF prior to and after pulmonary vein isolation, in extended AF segments (EAFS). We focus on patterns of RA, based on the hypothesis that AF drivers are transient but recur in the same locations. Methods. Five patients (61 ± 8 years of age, 3 male) for catheter ablation of psAF were included. 3D maps were collected with a double spiral 20 pole catheter. In stable locations, pre and post PVI, 37s EAFS were recorded using 8s segments, automatically every 1s, creating a 7s overlap between segments. Dominant cycle length (DCL) was determined for every 8s segment by a fully automated algorithm. RA was defined as the rapidest 20th percentile for each patient. RA episodes consisted of continuous segments with rapid DCL (black lines in Fig 1) and terminated with a non-rapid segment (red lines on Fig 1). Episodes were truncated where overlap occurred (Box 1 and Box 2 in Fig 1). The pattern of RA was assessed by the number, cumulative duration and mean duration of RA episodes within an EAFS pre and post PVI. Results. Mean DCL of EAFS increased significantly in 4/5 patients after PVI, the number of EAFS with rapid activity showed a reduction in all patients. The percentage of new sites with RA post PVI was 27%. The number of sites that retained RA post PVI was 14 ± 11.3 (58.3%; Table 1). Of these, number and cumulative duration of RA did not change in 4/5 patients, and mean duration of RA remained stable in 5/5. Conclusion. An automated DCL algorithm shows that, in most cases, global AFCL prolongs significantly with PVI overall, but selected foci retain RA and RA patterns. These may represent active drivers, as their activity appears to be independent of their surroundings. Table 1 Patient ID Number of segments Mean AFCL ± SD of all segments Number of EAFS with rapid activity Pre-PVI Post-PVI P Pre-PVI Post-PVI New sites 1 145 135 ± 8.9 141 ± 9.8 <0.001 94 62 15 2 121 154 ± 12.9 162 ± 15.0 <0.001 94 72 11 3 172 148 ± 13.7 160 ± 16.6 <0.001 108 82 25 4 301 172 ± 22.9 174 ± 21.5 0.418 198 189 58 5 200 177 ± 9.9 215 ± 18.1 <0.001 87 43 14 Pre and Post PVI cycle length and EAFS with rapid activity. (AFCL: AF cycle length; EAFS: Extended AF segments; PVI: Pulmonary vein isolation) Abstract Figure.