Heart rate and heart rate variability during sleep in small-for-gestational age newborns.
To assess the influence of intrauterine growth retardation on heart rate (HR) and HR variability during sleep, we performed polygraphic recordings in 10 small-for-gestational age (SGA) and 16 appropriate-for-gestational age (AGA) newborns. Both groups were clinically and neurologically normal and were at 37 to 41 wk conceptional age. RR intervals were analyzed using the short-time Fourier transform in three frequency bands: 1) high frequency, with a period 3-8 heartbeat; 2) mid frequency, with a period 10-25 heartbeat; and 3) low frequency, with a period 30-100 heartbeat. In both active and quiet sleep, SGA newborns significantly differed from AGA newborns by having a shorter RR interval (p < 0.01) and lower amplitude of HR variability in all bands (p < 0.05) except low frequency in quiet sleep. Quiet sleep differed from active sleep by having a longer RR interval (p < 0.05), higher high-frequency variability (p < 0.02) in both SGA and AGA newborns, and lower low-frequency variability (p < 0.005 for AGA newborns). Our data give evidence of clear modifications of both sympathetic and parasympathetic HR control in the at-risk SGA population. Similarity of between-state characteristics suggests maintained CNS control of HR in SGA as well as in AGA newborns. We speculate that between-group HR and HR variability differences may be related to augmented metabolic rate in SGA compared with AGA newborns.
Spassov
L
L
INSERM, Hôpital A. Béclère, Clamart, France.
Curzi-Dascalova
L
L
Clairambault
J
J
Kauffmann
F
F
Eiselt
M
M
Médigue
C
C
Peirano
P
P
D001481:Basal Metabolism; D001724:Birth Weight; D005260:Female; D005317:Fetal Growth Retardation / Q000503:physiopathology; D005865:Gestational Age; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000502:physiology*; D007741:Labetalol / Q000627:therapeutic use; D008297:Male; D008750:Methyldopa / Q000627:therapeutic use; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000188:drug therapy; D012890:Sleep / Q000502:physiology*
D008750:Methyldopa; D007741:Labetalol