Altered Heart Rhythm Dynamics in Very Low Birth Weight Infants With Impending Intraventricular Hemorrhage

Abstract

OBJECTIVE-Intraventricular hemorrhage remains an important problem among very low birth weight infants and may result in long-term neurodevelopmental disabilities. Neonatologists have been unable to accurately predict impending intraventricular hemorrhage. Because alterations in the autonomic nervous system's control of heart rhythm have been associated with intraventricular hemorrhage after its development, we sought to determine if early subtle alterations of heart rhythm could be predictive of impending intraventricular hemorrhage in very low birth weight infants.METHODS-This case-control study included 10 newborn very low birth weight infants with intraventricular hemorrhage (5 grade IV, 4 grade III, and 1 grade II) and 14 control infants without intraventricular hemorrhage. Heart rhythm data from the first day of life before the development of intraventricular hemorrhage were evaluated. Detrended fluctuation analysis, a nonlinear fractal heart rate variability method, was used to assess the fractal dynamics of the heart rhythm. Fractal scaling exponents were calculated by using this analysis.RESULTS-Twenty-four infants (mean ± SD, birth weight: 845 ± 213g: gestational age: 26.1 ± 1.9 weeks) participated in the study. The short-term scaling exponent was significantly larger in infants who later developed intraventricular hemorrhage compared with those who did not (0.60 ± 0.1 vs 0.45 ± 0.1). A value of 0.52 resulted in 70% sensitivity and positive predictive value and 79% specificity and negative predictive value. The short-term scaling exponent was the only significant predictor of intraventricular hemorrhage.CONCLUSIONS-Fractal dynamics of the heart rhythm is significantly altered in very low birth weight infants before developing intraventricular hemorrhage and may be predictive of impending intraventricular hemorrhage. 8,9 Given this important public health problem, it would be quite valuable to identify VLBW infants who are at highest risk for developing IVH, before they actually develop it, so that they may benefit from prevention and intervention strategies. Unfortunately, accurate prediction methodologies of impending IVH have not been developed.Altered autonomic function has been observed by heart rate variability (HRV) analysis in premature infants after IVH. 10-12 HRV refers to the beat-to-beat (R-R interval from the electrocardiogram) fluctuation of heart rate and reflects the balance between parasympathetic and sympathetic impulses to the heart that is under central nervous system control. Researchers have used HRV analysis as a tool to estimate autonomic neural control of the heart and for predicting impending arrhythmia 13 and long-term outcome of VLBW infants. 11,14 The objective of this study was to determine if impending IVH in VLBW infants may be predicted by altered autonomic function. We hypothesized that autonomic dysfunction precedes the development of IVH in VLBW infants. We used a nonlinear method, called detrended fluctuation analysis (DFA), 11,15 to examine the HRV characte...

Maternal Race, Demography, and Health Care Disparities Impact Risk for Intraventricular Hemorrhage in Preterm Neonates

“…[42] We did not collect physiologic measures of the cerebral circulation. [43, 44] Injury to the white matter of the brain is an important cause of neurodevelopmental impairment; we did not evaluate magnetic resonance imaging studies to detect white matter injury. Finally, the incidence of multiple gestation pregnancies in white mothers was almost double that in African ancestry mothers in our study and that finding may have influenced the analysis.…”

Patent ductus arteriosus in preterm infants is associated with cardiac autonomic alteration and predominant parasympathetic stimulation

“…The decrease in HF power was proportionally less than that of the LF power between the Control group and the PDA group, leading to a decrease in LF/HF ratio from 5.52 ± 3.28 (Control group) to 2.74 ± 1.67 (PDA group), consistent with parasympathetic dominance. In children and neonates, major reduction in HRV power has been described in intracerebral haemorrhage [9], severe sepsis [10], RDS, the aftermath of Fontan open-heart surgery [11] and pulmonary stenosis [12]. The low HRV power observed in our study in preterm infants with PDA (i.e.…”

Prediction of intraventricular haemorrhage in preterm infants using time series analysis of blood pressure and respiratory signals

“…In this case, the short-term scaling exponent was defined over 4–15 beats, as aligned with similar observations of this data9 and similarly defined for heart rate variability analysis of preterm infants8. The long-term scaling exponent was determined across 15–50 beats.…”

“…In particular, one study showed that these differences could be detected using electrocardiogram data from the first 24 hours of life8. Variability of beat-to-beat systolic blood pressure and mean arterial pressure has also been shown to offer useful information in distinguishing infants who later developed IVH from those who did not9.…”