Heart rate variability (HRV) reflects the complex interplay of the sympathe
tic and parasympathetic innervation of the heart. Developmental maturation
of the fetus and newborn results in predictable alterations in the neural c
ardiac control of heart rate. Furthermore, patterns of HRV are closely corr
elated to clinical outcome in several pathologic situations. The first aim
of this study was to characterize the maturational patterns of HRV in a gro
up of developmentally at-risk newborns (those with severe hemorrhagic or is
chemic brain injury and extremely immature, low-birth-weight infants). Seco
ndly, we sought to determine whether a correlation exists between HRV and l
ength of hospital stay, diagnosis of cerebral palsy, and neurodevelopmental
test scores at 1-year corrected age. Time domain indices of HRV were compu
ted longitudinally from 32 to 37 weeks of corrected gestational age in 19 v
ery low birth weight, preterm infants. Among the 19 infants studied, 7 infa
nts had no evidence of brain injury, 7 infants had periventricular leukomal
acia (PVL), 3 infants had grade III/IV intraventricular hemorrhage (IVH), a
nd 2 infants had both IVH and PVL. Neurologic injuries were documented usin
g ultrasound and neurodevelopmental progress was followed through 1 year of
corrected gestational age. A multivariate repeated measures analysis was p
erformed 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 patt
erns of HRV with multivariate regression models producing adjusted r(2) val
ues ranging from 0.63 to 0.99. The type of perinatal brain injury was highl
y correlated to the developmental outcome measures (p < 0.0000) with PVL pa
tients having the lowest neurodevelopmental scores, IVH patients having the
highest scores, and noninjured infants having midrange, grossly normal val
ues. 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 bra
in 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 patte
rn of HRV and HRV was highly correlated to length of hospital stay and neur
odevelopmental function assessed at 1 year of corrected gestational age. Co
pyright (C) 2000 Karger AG, Basel.