B-PO02-110 MIND THE GAP: ADVANCED MAPPING CAPABILITIES TO BETTER UNDERSTAND PULMONARY VEINS GAPS DURING REPEAT ATRIAL FIBRILLATION ABLATION

Abstract

Detailed characterization of pulmonary veins (PV) reconnection during repeat AF ablation through high-density mapping (HDM) and automated algorithms is still lacking. To characterize PV gaps and underlying electrical activity during and after ablation of PVs in AF patients (pts). Consecutive pts undergoing repeat AF ablation from the CHARISMA registry with complete characterization of PV gaps (PVG) at 6 centers were included. We performed a complete map of the left atrium and PVs through the Rhythmia HDM system. A novel map analysis tool (Lumipoint) that automatically identifies split potentials and continuous activation was used sequentially on each PV component, in order to better assess PVG. Local impedance (LI) characteristics were retrieved through a dedicated algorithm (DirectSense). The ablation endpoint was PVI as assessed by entrance and exit block. Thirty-eight PVGs were automatically identified through the Lumipoint tool in 18 cases, mostly at anterior sites (16, 42.1%) (median number of signal peaks = 5[3-7] peaks). The mean LI and LI drop at gap sites were 111±12Ω and 17±5Ω, respectively. The mean linear extension of PVGs detected through Lumipoint was significantly lower than the one recognized through voltage map (12.2±8 mm vs 14.9±9 mm, p=0.004) whereas was comparable to the one identified through conventional activation map (13.0±7 mm, p=0.3377 vs Lumipoint). Both LI and LI drop were correlated with the number of signal peaks (R=-0.66, 95%CI: -0.81 to -0.44, p<0.0001 for LI; R=-0.43, 95%CI: -0.66 to -0.13, p=0.0068 for LI drop, respectively). Stratifying PVGs through ><5 signal peaks (median value), both LI and LI drop values at PVGs were lower when the number of peaks at each spot was higher (LI: 117±11Ω with <5 peaks vs 103±8 >5 peaks, p=0.0002; LI drop: 18±4Ω with <5 peaks vs 15±5Ω >5 peaks, p=0.0357). At the end of the procedures, all PVs had been successfully isolated in all study pts. Advanced mapping capabilities were useful to pinpoint the search for PVGs, enabling a more targeted ablation approach vs relying on voltage mapping. LI values correlated well with PVGs characteristics.