Normal reference values for left atrial strains and strain rates in school children assessed using two-dimensional speckle-tracking echocardiography

Left atrium (LA) function is a known predictive marker of heart failure in adults. Few reports of LA function analyses using LA strain ( ɛ ) and strain rate (SR) measurements in children exist. Thus, this study aimed to determine normal reference values for LA ɛ and SR in healthy school children and to investigate methods of interpreting LA function data based on maturational changes using two-dimensional speckle-tracking echocardiography (2DSTE). We recruited 112 healthy school children (median age 12.0 years; range 6–16 years). LA ɛ and SR were investigated using 2DSTE multi-vendor analysis software (TomTec Imaging Systems, Germany) and compared to Doppler parameters and LA volumes measured by the conventional method. The onset of the P wave was selected as the reference point for the LA ɛ analysis. Normal ranges of LA ɛ [reservoir ( ɛ RS), conduit ( ɛ CD), or contractile ( ɛ CT)] and positive SR (SR POS ), early negative SR (SR EN ), and late negative SR (SR LN ) were obtained using Z -score models via the lambda-mu-sigma method. According to the Z -score curves, all ɛ showed slight falling or continuous flat lines against age, body surface area (BSA), or heart rate (HR); however, ɛ CT showed modestly positive associations with HR. As for SR, the Z -score curves showed falling lines against age and BSA. In contrast, Z -score curves for SR EN and SR LN showed rising lines against HR. SR EN was independent of E / e ′ and was negatively correlated with LA volume indexed against BSA. This study demonstrated the normal reference values for LA ɛ and SR using 2DSTE in school children. The present results recommended that LA ɛ should be evaluated together with changes in LA SR for accurate assessment, considering maturational changes including age, BSA, and HR in school children.