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Spectral analysis of heart rate variability in premature infants with feeding bradycardia
S Veerappan1, H Rosen, W Craelius
1Division of Neonatology, UMDNJ-Robert Wood Johnson Medical School, St. Peter's University Hospital, New Brunswick, New Jersey 08903, USA.
Insights
Premature infants experiencing feeding bradycardia show higher baseline parasympathetic activity. This heightened autonomic nervous system activity, specifically elevated high-frequency (HF) power, may explain their bradycardia during feeding episodes.
Area of Science:
- Neonatal physiology
- Autonomic nervous system regulation
- Cardiovascular research
Background:
- Bradycardia during feeding is a common concern in premature infants.
- The role of autonomic nervous system activity in feeding bradycardia requires further elucidation.
- Understanding the physiological underpinnings can inform clinical management strategies.
Purpose of the Study:
- To investigate baseline autonomic nervous system activity in premature infants with feeding bradycardia.
- To compare parasympathetic activity levels before and after feeding between infants with and without bradycardia.
- To identify potential physiological markers associated with feeding bradycardia.
Main Methods:
- Heart rate variability analysis using electrocardiogram (EKG) data.
- Spectral power analysis of very low (VLF), low (LF), and high (HF) frequency bands.
- Comparison of heart rate spectral components in preterm infants with feeding bradycardia versus controls.
Main Results:
- Infants with feeding bradycardia exhibited significantly higher baseline HF power (indicating parasympathetic activity) before feeding.
- A lower LF/HF ratio was observed in the bradycardia group, further supporting elevated parasympathetic tone.
- These differences were noted around 34 weeks post-conceptional age.
Conclusions:
- Elevated baseline parasympathetic activity is evident in premature infants who experience bradycardia during feeding.
- This heightened parasympathetic tone may be a contributing factor to the development of feeding-related bradycardia.
- Findings suggest a potential autonomic basis for feeding bradycardia in this vulnerable population.
Abstract:
An elevated level of baseline parasympathetic activity was noted in a group of premature infants suffering from bradycardia during feeding. At approximately 34 wk post-conceptional age, the heart rates of 12 infants with feeding bradycardia (birth weight = 1539 +/- 279 g; gestational age = 31.0 +/- 1.6 wk) and 10 controls (birth weight = 1710 +/- 304 g; gestational age = 32.0 +/- 1.4 wk) were recorded 1 h before and 1 h after feeding. EKG data were digitized and 3.2-min segments of data were analyzed to determine the spectral power at very low (VLF = 0.003-0.03 Hz), low (LF = 0.03-0.39 Hz), and high (HF = 0.40-1.00 Hz) frequencies. In preterm infants with feeding bradycardia, an elevation in baseline parasympathetic activity was evident before feeding, as indicated by significantly higher HF power and a lower LF/HF ratio. This elevation in baseline parasympathetic activity may contribute to the observed bradycardia during feeding.