The development of the circadian heart rate rhythm (CHR) in Asian infants

Abstract

Objective To test the hypothesis that term-born Asian infants, at reduced risk to die of Sudden Infant Death Syndrome (SIDS) exhibit a circadian heart rate rhythm (CHR) at a later age than non-Asian term infants. Method Repeated overnight heart rate (HR) traces obtained with a battery-operated Polar S810i heart-rate monitor at home in 17 Asian Torajan infants in Indonesia, were compared with those of 52 non-Asian infants monitored as part of the Collaborative Home Infant Monitoring Evaluation (CHIME). HR was determined using a moving window averaging technique. A comparison of median HR during quiet sleep (QS) episodes (identified by minimum HR variability), established the presence of CHR. Results Seventy three percent of non-Asian CHIME infants ≤ 7 weeks exhibited CHR compared to 45% of Asian Torajan infants. Between 8 and 12 weeks, 94% of non-Asian CHIME infants exhibited CHR, compared to 33% of Asian Torajan infants (p < 0.001). Forty seven and 56% of Asian Torajan infants exhibited the CHR at the age intervals of 16–20 weeks and 21–25 weeks respectively. Active wakefulness percentages as a function of the entire recording and median QS HR were not significantly different in the two groups. Conclusion Despite the fact that Asian Torajan infants were on average a week older than non-Asian CHIME babies, between two and three months of age only one in three exhibited the CHR, compared to virtually all non-Asian CHIME infants. We speculate that the cause of this difference rests in the infants' environment rather than their genetic origin.

Beginning to See the Light: Lessons Learned From the Development of the Circadian System for Optimizing Light Conditions in the Neonatal Intensive Care Unit

“…Around the same time, day-night differences can also be observed in hormone production, such as melatonin from 12 weeks of age ( Kennaway et al, 1992 ). In addition to rhythms in hormone production, heart rate shows a clear difference between day and night from 7 weeks onward ( Hoppenbrouwers et al, 2012 ), whereas day/night differences in body temperature only become apparent from 2 months of age ( Petersen and Wailoo, 1994 ). Whether the developmental timeline of these rhythms is influenced by the postnatal environmental light-dark cycle in preterm infants is unclear, as reviewed above.…”

Test-Retest Reliability of Pediatric Heart Rate Variability

“…Guidelines do not specify an ideal time of day for recording ECG, leaving this study protocol decision to the discretion of researchers. Circadian variations in HRV have been observed in adults (e.g., Armstrong, Kenny, Green, & Seely, 2011), children (e.g., Massin, Maeyns, Withofs, Ravet, & Gerard, 2000), and infants as early as 7–12 weeks old (Hoppenbrouwers et al, 2012). Sympathetic dominance peaks just after awakening and withdraws during the day, while parasympathetic, or vagal, dominance becomes augmented throughout the night, reaching its peak before awakening (Guo & Stein, 2003; Huikuri et al, 1990).…”