Left atrial morpho-functional remodeling in atrial fibrillation assessed by three dimensional speckle tracking echocardiography and its value in atrial fibrillation screening

Abstract

Background: Three dimensional speckle tracking echocardiography (3D STE) is a novel technique combining 3D echocardiography and speckle tracking analysis. 3D STE software dedicated to the left atrium (LA) was recently available. Our study aimed to assess (1) atrial fibrillation (AF) related LA morpho-functional remodeling using 3D STE and (2) value of LA function parameters in identifying paroxysmal AF (PAF).

Methods: One hundred thirty-nine PAF, 109 persistent AF (Per-AF) and 59 non-AF subjects underwent 3D STE. LA phasic volumes and total LA emptying fraction (LAEF) were obtained and used to calculate passive (pLAEF) and active LA emptying fraction (aLAEF) based on atrial contraction. LA longitudinal and circumferential strain representing reservoir (LASr/LASrc), conduit (LAScd/LAScdc) and pump (LASct/LASctc) function were also assessed.

Results: 3D STE was found to have good reproducibility. Increase of LA volumes and decrease of parameters representing LA reservoir and pump function were independently associated with AF as well as AF burden. The correlations between LA emptying fraction and LA circumferential strain representing the same function were always stronger than those with LA longitudinal strain (p < 0.001). Minimal LA volume, LAEF, aLAEF, LASrc and LASctc can be used to accurately differentiate PAF from non-AF subjects (AUC > 0.8) with great sensitivity and specificity.

Conclusions: Assessing LA remodeling in AF using 3D STE was feasible. AF and AF burden were independently associated with LA enlargement and impairment of reservoir and pump function but not conduit function. LA function parameters can indicate underlying PAF and thus can guide AF screening strategy.

Keywords: Atrial fibrillation; Left atrial function; Left atrial strain; Remodeling; Three dimensional speckle tracking echocardiography.

Fig. 1

An example of motion tracking analysis of LA using 4D Auto LAQ, Echopac, GE Health. A Display of acquired LA 3D images showing apical four-chamber, two-chamber, three-chamber plane on the left and 9 slices of short-axis views from mitral annular plane to the atrial roof. B Landmark setting stage with three landmarks set at proper places according to the instruction. C Review stage with the LA endocardial contour traced. D A simulated model of reconstructed LA and output parameters. E LA strain/volume-time curve

Fig. 2

An example of the (longitudinal/circumferential) LA strain-time curve. ED = end ventricular diastole, ES = end ventricular systole, PreA = pre atrial contraction