Determinants of Heart Rate in Newborns

This paper presents an overview of cardiac chronotropic regulation determinants in newborns, which are reflected in mean heart rate (HR) and heart rate variability (HRV). Heart rate and heart rate variability in newborns are determined by many factors. Heritability and maturation play major role. Factor of the maturation can be seen in HR and HRV differences between healthy full term and preterm newborns as well as in changes over early postnatal time. These parameters in newborns are influenced also by many other factors as gender, nutrition, sleep, breathing pattern/ventilation, etc.

Autoregulation and extrinsic regulation of cardiac activity has its own specificities in newborns. Homeometric mechanism (depended on HR) is dominant and baroreflex sensitivity is reduced, mainly in premature newborns. Complex cardiac regulation can be studied and evaluated by cardiac reflexes. Examination of the reflexes in newborns is limited. Therefore, new approaches for the study of maturation cardiac control are developed taking into consideration all cardiac activity in newborns determinants.