The effect of a periodic thermal stimulus on heart rate in the term
newborn infant.
Hathorn, Michael K. S., Paul A. Mannix, and Kate Costeloe.
University of London: a Joint Academic Department of Child Health
of the Medical College of St Bartholomew's Hospital and the London
Hospital Medical College, and b Department of Physiology, Queen Mary
and Westfield College
APStracts 2:0219A, 1995.
We studied heart rate changes in 25 term infants aged 1-7 days in
quiet sleep during periodic thermal stimulation of one foot, in order
to widen the range of frequencies previously studied by others; and
to develop spectral analysis methods to quantify responses to thermal
and other periodic sensory stimuli. The stimulation frequency was
0.10 Hz in all babies, and ranged from 0.05 to 0.15 Hz in some. At
0.10 Hz, there was (a) an increase in spectral power at the frequency
of stimulation (p<0.001); (b) a tendency for overall low frequency
power to increase; (c) a reduction in respiratory sinus arrhythmia
(p<0.025); and (d) attenuation in the response between the first
and second minutes of stimulation (p<0.01). At other frequencies of
stimulation, essentially similar results were obtained. Respiration
and other types of periodic sensory stimulation may also entrain the
heart rate; we raise the question of whether low frequency
oscillations in heart rate are in fact related to thermoregulation,
or are a non-specific feature of integrative processes in the
brainstem.
Received 22 November 1994; accepted in final form 12 May 1995.
APS Manuscript Number A1195-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 May 1995.