Po-01-163 characterization of atrial substrate using close-coupled paced electrogram feature analysis (pefa) in patients with non-valvular atrial fibrillation

Mapping strategies that lead to a better understanding and therapy for persistent atrial fibrillation (AF) are urged. Paced electrogram feature analysis (PEFA) exposes slow conduction zones as substrate for ventricular arrhythmias and previous studies support its efficacy for guiding ablation. PEFA has not been studied in the left atrium (LA). Our goal was to demonstrate that PEFA exposes slow conduction areas in the LA that may trigger and perpetuate AF. Prospective exploratory cohort study. The intervention group was formed by patients with paroxysmal AF undergoing catheter ablation (Group A), compared to a control group of patients without AF and structurally normal heart presenting for left-sided electrophysiological procedures (Group B). Antiarrhythmic drugs were discontinued at least five half-lives before the study and amiodarone, at least 3 months LA effective refractory period (AERP) was defined while pacing from the LA appendage (LAA). PEFA protocol consisted of a paced (S1) at 600 ms with an extra stimulus (S2) at a fixed coupling interval of AERP+30ms. EGM conduction time (time from pacing artifact to first deflection), EGM latency (conduction time from pacing artefact to local activation time of the S2 less same value for S1), EGM duration (first deflection to last deflection), EGM propagation time (latency + EGM duration), and last deflection (sum of CT + EGM duration) were defined (Figure 1). Group B data was used as the reference values, the percentage of abnormal EGM features in group A compared to group B were calculated. Twenty-four AF and 8 control patients were included. EGM features were evaluated in 13 different locations of the LA with a total of 12,291 EGMs to analyze (Table 1). Compared to non-AF controls, AF patients had a higher percentage of abnormal latency (10.43%, p<0.001), propagation time (12.04%, p<0.001), and last deflection (10.49%, p<0.001) for all locations evaluated together, however, the LA roof expressed more remarkable abnormal EGM properties than other areas (Table 1). There was no statistically significant difference in EGM duration between groups (p=0.83). PEFA exhibits abnormal conduction properties (latency, propagation time and last deflection) in certain areas of the LA. This may be used in the future to characterize AF substrate; objective assessment of these responses may inform ablation sites in patients with atrial fibrillation and warrants further study.Tabled 1Paced electrogram fractionation characteristics in patients with AF (Group A) and controls (Group B)EGM characteristicLatency (CT in S2 less CT in S1)Propagation (latency + EGM duration)Last deflection (sum of CT + EGM duration)Group A (N=9823)Time in ms (SD)Group B (N=2464)Time in ms (SD)% Abnormalp-valueGroup A (N=9823)Time in ms (SD)Group B (N=2464)Time in ms (SD)% Abnormalp-valueGroup A (N=9359)Time in ms (SD)Group B (N=2468)Time in ms (SD)% Abnormalp-valueAll54.7 (27.7)45.4 (21.9)10.43%<0.001*111.1 (35.9)101.6 (25.7)12.04%<0.001*172.0 (43.0)157.7 (31.5)10.49%<0.001*Anterior wall51.3 (28.4)45.1 (18.1)11.17%<0.001*113.2 (35.7)98.1 (22.3)19.39%<0.001*158.9 (34.7)154.5 (33.3)6.195%0.057Floor52.9 (27.2)36.6 (22.3)18.06%<0.001*109.2 (35.5)96.6 (28.3)10.31%<0.001*168.2 (44.7)149.8 (32.8)11.30%<0.001*LAA43.6 (40.5)32.7 (24.6)2.80%0.001*106.7 (48.2)100.4 (32.5)6.54%0.1192138.8 (48.2)131.0 (28.3)9.91%0.047*Left anterior wall55.0 (22.6)45.3 (18.0)14.34%<0.001*109.5 (29.5)104.4 (23.6)7.46%0.005*175.4 (38.4)153.6 (22.6)14.14%<0.001*LIPV33.8 (30.3)52.8 (14.4)6.94%<0.001*79.3 (36.7)96.9 (18.8)7.67%0.009*151.7 (34.5)161.0 (17.8)6.99%0.1470LSPV44.6 (34.7)54.4 (17.3)9.38%0.011*101.7 (44.3)102.7 (24.2)13.13%0.8265173.9 (33.8)169.0 (23.3)6.25%0.2189Mitral isthmus46.0 (26.0)43.6 (26.1)0.94%0.3334105.5 (35.0)101.3 (29.8)5.82%0.19137.5 (38.7)128.0 (29.2)7.36%0.006*Posterior wall53.9 (23.6)41.7 (16.7)19.26%<0.001*108.8 (33.2)92.5 (16.8)25.64%<0.001*178.6 (38.0)151.8 (21.4)27.61%<0.001*Right anterior wall62.1 (26.4)55.5 (15.8)17.47%<0.001*112.6 (33.7)109.3 (24.9)11.43%0.01191.6 (46.5)179.4 (24.7)14.08%<0.001*RIPV53.8 (13.1)60.3 (12.3)4.00%<0.001*97.1 (33.2)98.4 (18.1)6.4%0.01182.8 (32.8)184.5 (16.2)3.01%0.0682Roof57.1 (22.5)46.9 (17.3)26.63%<0.001*117.3 (30.3)100.2 (28.3)39.95%<0.001*175.5 (34.3)154.0 (49.5)36.96%<0.001*RSPV72.6 (27.0)63.5 (15.1)18.47%0.003*128.8 (46.3)113.4 (28.6)16.30%0.003*199.3 (29.5)200.4 (23.1)4.324%0.7597Septum61.7 (27.7)44.4 (28.0)10.64%<0.001*118.3 (37.7)106.4 (28.2)15.51%<0.001*184.6 (37.6)161.7 (30.2)12.61%<0.001**Statistically significant, CT: Conduction time, EGM: Electrogram, LAA: Left atrium appendage, LIPV: Left inferior pulmonary vein, LSPV: Left superior pulmonary vein, RIPV: Right inferior pulmonary vein, LIPV: Left inferior pulmonary vein. Open table in a new tab