Normal values and distribution of ventricular global longitudinal strain in 513 healthy fetuses measured by two-dimensional speckle-tracking echocardiography: a multi-institutional cohort study.

This study aimed to determine the normal reference values and distribution of global longitudinal strain (GLS) in the right and left ventricles of healthy Japanese fetuses during pregnancy. This multi-institutional cohort study included healthy Japanese fetuses during normal pregnancies without maternal or fetal complications between 18 and 40 weeks of gestation. Two-dimensional fetal echocardiographic images of the four-chamber view with a high frame rate were acquired and stored as DICOM clips. Data were collected and analyzed in a central laboratory to measure the left ventricular (LV) and right ventricular (RV) GLS using two-dimensional speckle tracking. In total, 513 fetuses were enrolled. The mean LV-GLS and RV-GLS were - 24.3% ± 3.5% and - 23.5% ± 3.7%, respectively. The magnitude of the GLS, with normal limits in both ventricles, decreased with advancing gestation. LV values were r = 0.34 (95% confidence interval, 0.27-0.42) and p  < 0.0001; RV values were r = 0.33 (95% confidence interval, 0.25-0.41) and p  < 0.0001. The normal values of healthy Japanese fetuses in healthy pregnancies is the first to be established by the large-scale, multi-institutional cohort study as LV-GLS of 24.3% ± 3.5% and RV-GLS of - 23.5% ± 3.7%, respectively. This can serve as a basic reference for assessing the cardiac functions in Japanese fetuses with various heart diseases.