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Minute-by-minute association of heart rate variation with basal heart rate in developing infants
1Brain Research Institute, UCLA School of Medicine 90024-1761.
Insights
Heart rate variation in infants changes with sleep state and age. Autonomic nervous system development shows a notable shift around one month, impacting these heart rate patterns.
Area of Science:
- Developmental neuroscience
- Cardiovascular physiology
- Infant autonomic function
Background:
- Heart rate variation (HRV) patterns are known to change with heart rate, typically diminishing at higher rates.
- Understanding the developmental trajectory of these correlations in infants is crucial for assessing autonomic nervous system maturation.
Purpose of the Study:
- To investigate the developmental patterns of correlations between median heart rate and different types of heart rate variation in normal infants.
- To examine how these correlations are influenced by sleep-waking states (quiet sleep, REM sleep, waking) across the first six months of life.
Main Methods:
- Polygraphic recordings were collected from 25 infants at multiple time points from 1 week to 6 months of age.
- Median heart rate and heart rate variation at three distinct frequencies were analyzed per 1-minute epoch.
- Pearson's correlation coefficient (r) was used to assess the relationship between heart rate and HRV measures, analyzed separately for sleep and waking states.
Main Results:
- Maturational patterns of heart rate-HRV correlations were significantly influenced by the sleep-waking state.
- These developmental patterns differed from previously reported correlations between cardiac and respiratory measures.
- A discontinuity in autonomic development was observed around 1 month of age.
Conclusions:
- Infant heart rate regulation and its variation exhibit distinct developmental trajectories influenced by sleep state.
- The findings suggest asynchronous development between the autonomic and somatic motor systems.
- A potential shift in sleep state characteristics linked to developing forebrain connections may underlie these observed autonomic development trends.
Abstract:
Particular types of heart rate variation are enhanced during periods of slow heart rate and diminished when heart rate is high. We examined how the correlations between heart rate and various types of heart rate variation developed in normal infants. Polygraphic recordings were obtained from 25 infants at 1 week and at 1, 2, 3, 4 and 6 months of age. Median heart rate and the extents of heart rate variation at three distinct frequencies were determined for each 1-minute epoch. Pearson's r was used to assess the correlation of median heart rate in each epoch with each of three types of heart rate variation. For each recording, correlations were assessed separately for quiet sleep, rapid eye movement (REM) sleep and waking. The maturational patterns of heart rate by heart rate variation correlations were strongly influenced by sleep-waking state and were dissimilar to those previously reported for correlations between cardiac and respiratory measures. The findings suggest dissimilar developmental patterns for autonomic and somatic motor systems, and include a discontinuity in autonomic development at approximately 1 month of age. We speculate that these trends reflect a change in the nature of sleep states as forebrain connections develop.