Abstract
AIMS: Left atrial strains [reservoir (LASr), conduit (LAScd), and contractile (LASct)] are increasingly utilized, primarily in the areas of heart failure and valvulopathy. Commercially available software to measure strain are marketed as imaging machine vendor independent, although the normal ranges of their performance and external validation studies are lacking. We evaluated and compared LAS values, reference ranges, and associated factors using contemporary strain software. METHODS AND RESULTS: Healthy subjects (n = 100) undergoing transthoracic echocardiography during January to April 2023 were studied, with equal number by age groups, sex, and GE vs. Philips equipment. LASs were quantified using TomTec version 51.02 (AutoStrain LA), EchoPAC version 206 (AFILA), velocity vector imaging (VVI) version 2.00, and Epsilon version 5.0.2.11295 software. Means and lower limits of normal [95% confidence interval (CI)] of LASr (%) were 44.1 (41.9, 46.3) and 30.3 (26.4, 34.1) for TomTec; 34.8 (33.6, 36.0) and 26.3 (24.2, 28.4) for EchoPAC (on GE scans only); 42.5 (40.2, 44.8) and 28.4 (24.4, 32.4) for VVI; and 37.0 (34.9, 39.1) and 25.2 (21.5, 28.8) for Epsilon. Factors significantly associated with variability in LASr measurements and their beta-coefficients (95% CI) were age -2.37 (-3.41, -1.33) per 10 years, EchoPAC (vs. TomTec) -9.63 (-12.75, -6.51), and Epsilon (vs. TomTec) -7.04 (-9.40, -4.67). Reference ranges and factors significantly associated with LAScd and LASct were reported. LAS measurements and normal ranges by strain software and associated clinical and echocardiographic factors were determined. CONCLUSION: EchoPAC and Epsilon have lower magnitude mean LAS values compared with TomTec and VVI, and all software were vendor neutral except EchoPAC.