P318 Left atrial dysfunction assessed by echocardiography in relation to left atrial fibrosis in patients undergoing ablation for atrial fibrillation

Abstract

Abstract PURPOSE Left atrial (LA) fibrosis is the hallmark of LA remodeling in atrial fibrillation (AF), alters LA function and may predict poor catheter ablation (CA) outcome. LA fibrosis may be assessed invasively using electroanatomical mapping (EAM) during electrophysiological study. The aim was to assess LA function parameters in relation to degree of LA fibrosis derived from EAM in patients with AF. METHODS Patients (pts) n = 39 (79% males, mean age 56+/-10) with non-valvular AF were studied with TTE and TEE before first CA during sinus rhythm. LA strain (LAS) and strain rate (LASR) were analyzed in reservoir (r), conduit (cd) and contractile (ct) phases. The velocities of mitral A, E" and A" were measured with Doppler. E/E" and LA stiffness index - the ratio of E/E" to LASr were assessed. LA appendage flow velocity (LAAv) was measured in TEE. LA volume using biplane area-length method was calculated. The EAM of LA was build using Carto System before CA. Low amplitude potentials area (LAPA) was quantitatively analyzed and expressed as a percentage of LA surface using the cut-off <0.5 mV to detect sites of fibrosis. LA parameters were compared between mild (LAPA <10%) moderate (LAPA 10-40%) and extensive degree of LA fibrosis (LAPA >40%) (table). RESULTS The mean LA volume was 35 ± 11 mL/m². The LAPA ranged from 2 to 78 % of LA surface. Reduced LA function was observed in the LAPA >40% group. Extensive LAPA altered mainly LA compliance parameters. Traditional LA systolic function parameters did not differ in relation to degree of LAPA. CONCLUSION LA compliance is mostly affected by LA fibrosis, thus LA diastolic parameters may be useful in the noninvasive assessment of LA fibrosis. Whether these parameters should be a part of the proper selection of candidates for CA requires further studies. LA function parameters LA parameters Group 1 LAPA <10% n = 13 Group 2 LAPA >10% <40% n = 13 Group 3 LAPA >40% n = 13 P-value Group 1 + 2 vs 3 Mitral A 0.55 ± 0.10 0.55 ± 0.24 0.73 ± 0.32 0.077 A" 9.19 ± 1.74 7.85 ± 1.43 7.92 ± 2.40 0.376 LASr 31.48 ± 4.52 26.48 ± 8.79 19.63 ± 6.76 <0.001 LAScd 17.30 ± 3.05 15.44 ± 6.93 10.91 ± 4.04 0.003 LASct 14.18 ± 5.36 11.05 ± 3.67 8.72 ± 4.78 0.024 LASRr 1.22 ± 0.19 1.24 ± 0.21 0.92 ± 0.20 <0.001 LASRct -1.71 ± 0.46 -1.37 ± 0.34 -1.04 ± 0.33 <0.001 LA stiffness 0.20 ± 0.07 0.34 ± 0.17 0.63 ± 0.29 <0.001 LAAv 0.83 ± 0.18 0.55 ± 0.17 0.60 ± 0.16 0.178