PO-02-172 CONDUCTION VELOCITY AND CONDUCTION VELOCITY DYNAMICS IN THE LEFT ATRIUM ARE IMPACTED BY STRUCTURAL AND AUTONOMIC MODULATION AND SITES OF CONDUCTION VELOCITY HETEROGENEITY CORRELATE TO RE-ENTRY ACTIVITY IN ATRIAL FIBRILLATION

Structural and autonomic remodelling is proposed to drive atrial fibrillation (AF). Conduction velocity (CV) heterogeneity predisposes cardiac tissue re-entry mechanisms. The impact of structural on CV dynamics formation unclear. Evaluate the modulation has activity in AF. Local activation times (LATs), voltage geometry data were obtained from 20 patients undergoing catheter ablation for persistent LATs at 3 pacing intervals (PI) (600, 400 250ms) with two sites. used determine their relationship using an automated algorithm. Relationship between sites enhanced defined as rate dependent slowing (RDCV) (sites exhibiting difference (CVd) PI=600ms PI=250ms ≥20% mean CVd seen these PIs that zone) AF was evaluated. Re-entry identified algorithm ≥1.5 rotations 360 degrees. both pharmacologically ganglionated plexi stimulation assessed. A total 512,082 LAT points analysed. Voltage impacts (1.36±0.98 nLVZ ≥0.5mV, 1.05±1.03 LVZ 0.2-0.49mV 0.58±0.37 vLVZ <0.2mV) (Figure 1A-B) dynamics, whereby curves are steeper (0.03±0.02ms PI 600-400ms, 0.54±1.1ms 400-250ms), broader (0.16±0.09ms 0.23±1.1ms 400-250ms) flat (0.04±0.01ms 0.05±0.02ms 1C). Per patient, 5.6±1.1 RDCV 3.4±1.3 identified. Of sites, 72.3% (81/112) correlated 94.1% (64/68) which mainly confined LVZs (59/68, 86.8%). Autonomic affected dynamic through increasing dependency 1D). number following (3.4±1.2 increase per patient). CVs impacted by influenced enhances heterogeneity. correlate Assessment heterogenity may help mechanistic importance LVZs.