摘要：Background.and.aim: A fuller und.rstand.ng of the neural control mechanisms o f heart rate d.ring the early stages of human d.velopment would.be of great valu e to obstetric and.neonatal management. In this paper, we investigate the correlation between he art rate variability (HRV) and.other physiological parameters such as blood.pres sure and.respiration in preterm neonates with the aim of d.veloping a numerical mod.l to explain and.pred.ct heart rate variability. Stud. d.sign and.subjects: All the required.d.ta are read.ly available for premature babies who are routine ly monitored.while being nursed.in intensive care, and.we have collected.large d.ata sets for a rand.m group of such neonates. For the quantitative analysis of t he d.ta, we have d.veloped.a time d.main correlation method. which has a number of ad.antages over the more commonly used.power spectral analysis. We have been able to stud. the d.namics of the d.fferent frequency components of HRV by this method. Results: Highly correlated.behaviour of the d.fferent HRV components, pr eviously observed.in our work on fetal HRV, is also present in the neonate, with similar characteristic time constants. Furthermore, the correlation of high- f requency (HF) oscillations of HRV with respiration and.that of low frequency (LF ) oscillations of HRV with blood.pressure are d.monstrated.on timescales of a si ngle oscillation. In neonates receiving artificial ventilation, the correlation between HRV and.respiration d.pend. on the type of ventilation involved.and.assu mes opposite polarities for the two main types of equipment currently in use. Co nclusion: We d.monstrate that it is possible to analyse HRV quantitatively by ca lculating the relative gains and.characteristic time constants for the correlate d.parameters and.components.