Po-03-103 omnipolar voltage mapping during af effectively overcomes the impact wavefront collision and fractionation has on bipolar voltage maps and more effectively identifies sites of pv reconnection at previous wide area circumferential lines compared to bipolar voltage maps

Voltage maps are used to assess atrial scar in patients undergoing ablation for atrial fibrillation (AF) but optimal methodology for assessing voltage is undefined. Evaluate different methods for assessing atrial voltage, and their accuracy in identifying pulmonary vein reconnection sites in AF. Patients undergoing ablation for persistent AF were included. Those undergoing first time ablation had omnipolar voltage (OV) and bipolar voltage (BV) maps collected in AF and a BV map in sinus rhythm (SR). AF OV and BV maps were compared. Activation vector and fractionation maps were reviewed at voltage discrepancy sites. AF maps were compared to SR BV maps. In patients undergoing redo ablation, the ability of OV and BV maps in AF to detect gaps in wide area circumferential ablation (WACA) lines were assessed and correlated with pulmonary vein (PV) reconnection sites. Forty patients were included (61.3±10.6 yrs., 85.0% male). Twenty patients undergoing initial ablation were assessed. Sixty voltage maps were reviewed (20 OV maps in AF, 20 BV maps in AF and 20 BV maps in SR). Across 17333±4233 points, comparing OV and BV maps in AF, there was 0.20±0.36 mV difference in voltage and 13.2±5.3% difference in the proportion of low voltage points (<0.5mV). The proportion of LA body occupied by low voltage zones (LVZ) was lower on OV maps (27.7±11.9% OV vs. 50.4±14.8% BV; p<0.001) (Figure 1A-B). In LVZ identified on BV maps and not on OV maps, 96.4±12.4% correlated to wavefront collision and fractionation sites (Figure 1C-D). Comparing co-registered points between the AF and SR maps, OV maps showed a lower discrepancy in voltage compared to BV maps (0.14±0.05mV vs. 0.31±0.07mV; p<0.001) (Figure 1E). Whilst BV maps in AF showed a disagreement with BV maps in SR by Bland-Altman analysis, OV maps did not. In the 20 patients undergoing redo ablation a total of 68 (3.5±1.1 per patient) and 42 gaps (2.1±0.7 per patient) were identified on OV and BV maps respectively. Of the 62 PV reconnection sites, 58 (93.5%) and 38 (61.3%) correlated to gaps on OV and BV maps respectively (Figure 1F-H). OV maps showed a high accuracy in identifying gaps in WACA lines that correlated to PV reconnection sites (AUC=0.89, p<0.001). OV AF maps improve voltage assessment by overcoming the impact of wavefront collision and fractionation. OV AF maps correlate better to BV maps in SR and better identify gaps on WACA lines that correlate to PV reconnection sites.