Heart rate variability in preterm brain-injured and very-low-birth-weight infants

• Published in: Biology of the neonate Vol. 77; no. 3; pp. 147 - 155
• Main Authors: HANNA, B. D, NELSON, M. N, WHITE-TRAUT, R. C, SILVESTRI, J. M, VASAN, U, MELEEDY REY, P, PATEL, M. K, COMISKEY, E
• Format: Journal Article
• Language: English
• Published: Basel Karger 01.01.2000; S. Karger AG
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Cerebral Hemorrhage - physiopathology; Cerebral Ventricles; Child Development; Emergency and intensive care: neonates and children. Prematurity. Sudden death; Heart Rate; Humans; Infant, Low Birth Weight - physiology; Infant, Newborn; Infant, Premature - physiology; Intensive care medicine; Length of Stay; Leukomalacia, Periventricular - physiopathology; Medical sciences; Nervous System - growth & development; Prognosis; Risk Factors; Premature; Cerebral infarction; Psychomotor development; Nervous system diseases; Prognosis; Pregnancy disorders; Variability; Cardiovascular disease; Cerebral disorder; Vascular disease; Very low birthweight; Heart rate; Newborn diseases; Periventricular leukomalacia; Cerebral hemorrhage; Central nervous system disease; Cerebrovascular disease
• ISSN: 0006-3126; 1661-7800; 1421-9727; 1661-7819
• DOI: 10.1159/000014209

Heart rate variability (HRV) reflects the complex interplay of the sympathetic and parasympathetic innervation of the heart. Developmental maturation of the fetus and newborn results in predictable alterations in the neural cardiac control of heart rate. Furthermore, patterns of HRV are closely correlated to clinical outcome in several pathologic situations. The first aim of this study was to characterize the maturational patterns of HRV in a group of developmentally at-risk newborns (those with severe hemorrhagic or ischemic brain injury and extremely immature, low-birth-weight infants). Secondly, we sought to determine whether a correlation exists between HRV and length of hospital stay, diagnosis of cerebral palsy, and neurodevelopmental test scores at 1-year corrected age. Time domain indices of HRV were computed longitudinally from 32 to 37 weeks of corrected gestational age in 19 very low birth weight, preterm infants. Among the 19 infants studied, 7 infants had no evidence of brain injury, 7 infants had periventricular leukomalacia (PVL), 3 infants had grade III/IV intraventricular hemorrhage (IVH), and 2 infants had both IVH and PVL. Neurologic injuries were documented using ultrasound and neurodevelopmental progress was followed through 1 year of corrected gestational age. A multivariate repeated measures analysis was performed to determine the relationship between the type of perinatal brain injury and neurodevelopmental status at 1 year of corrected gestational age. The type of perinatal brain injury was highly correlated to specific patterns of HRV with multivariate regression models producing adjusted r(2) values ranging from 0.63 to 0.99. The type of perinatal brain injury was highly correlated to the developmental outcome measures (p < 0.0000) with PVL patients having the lowest neurodevelopmental scores, IVH patients having the highest scores, and noninjured infants having midrange, grossly normal values. Using ANOVA, HRV was correlated to outcome, but individual comparisons revealed statistical significance only for the noninjured group (p < 0.04). However, multivariate models, which characterized outcome within each brain injury group, were highly significant (adjusted r (2) ranged from 0.23 to 0.89). In summary, the type of perinatal brain injury determined the pattern of HRV and HRV was highly correlated to length of hospital stay and neurodevelopmental function assessed at 1 year of corrected gestational age.