PO-04-030 PREDICTORS OF LOW VOLTAGE IN POSTERIOR WALL AND ASSOCIATION WITH ABLATION OUTCOMES

Abstract

Areas of low voltage electrograms (<0.5 mV) (LVA) are known to correlate with areas of atrial fibrosis and are related to clinical outcomes after ablation for atrial fibrillation (AF). To identify predictors of posterior wall (PW) LVA and associate PW LVA with ablation outcomes. Patients with AF who underwent PW and PVI ablation were included. Pre-ablation voltage map data was obtained from CARTO and LVA was recorded. Patients were considered to have LVA if there was any voltage <0.5 mV in the PW. Patient characteristics and outcomes were also recorded. Time to ablation was defined as time from AF diagnosis to ablation. Recurrence <1 year was noted if AF was detected between 3 months and 1 year, to allow for 3-month blanking period. A total of 80 patients were included: 38 (47.5%) had PW LVA with a mean area of 3.54 + 5.76 cm2 (median 1.1, IQR .5-3.6), 42 (52.5%) had no PW LVA. Duration of AF was associated with presence of PW LVA: 18.42% of patients with paroxysmal AF had low voltage area, 21.05% for persistent AF, 60.53% for longstanding persistent (p = 0.036). Predictors of PW LVA are included in figure 2. Patients who sought ablation greater than 1 year after diagnosis of AF had larger PW LVA (2.2 + 5.19 cm2 vs 0.67 + 1.2, p = 0.13). Seventy-five patients had 1-year follow up at 366.52 + 69.23 days after ablation. Mean follow up was 899.98 + 453.72 days. Recurrence rates were higher in those with PW LVA compared to those without PW LVA at both <1 year (26.32% vs 9.52%, p = 0.048) and >1 year (42.11% vs 23.81%, p = 0.08). Respective odds ratios for recurrence at <1 year and >1 year based on presence of PW LVA was 3.39 (p = 0.05) and 2.32 (p = 0.08). Patients without PW LVA had higher incidence of atrial flutter before 1-year follow up (21.43% vs 5.26%, p = 0.036). CHADS2-VAsc score, vascular disease and duration of AF are positive predictors of PW LVA. Presence of PW LVA is associated with higher recurrence rates after ablation, however lower incidence of atrial flutter.