Estimating Left Ventricle Ejection Fraction Levels Using Circadian Heart Rate Variability Features and Support Vector Regression Models. - Alkhodari, Mohanad; Jelinek, Herbert F.; Werghi, Naoufel; Hadjileontiadis, Leontios J.; Khandoker, Ahsan H. (IEEE Journal of Biomedical & Health Informatics, 2021)