The electronic evaluation of the fetal heart rate

Hon, Edward H.; Bradfield, Alan; Hess, Orvan W.

doi:10.1016/0002-9378(61)90061-8

Cited by 74 publications

(22 citation statements)

References 25 publications

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“…before it can phasically activate the sympathetic branch~although circulating catecholamines are present and provide adrenergic tone on the heart; Tucker, 1985!. Although absolute heart period is considerably shorter in rats than humans, in many ways, autonomic control of cardiac rate is similar in the two species. For example, fetal humans and early postnatal rats both show large bradycardias to environmentally significant events that appear to be mediated mostly by parasympathetic influences~although the evidence concerning autonomic mediation in humans is scarce; Hon, Bradfield, & Hess, 1961;Renou, Newman, & Wood, 1969!. In addition, in adult humans and rats, we see the same relatively broad range of control over heart period by the parasympathetic branch compared to a much narrower range of sympathetic control over heart period~approxi-mately 6:1 in rats and 7:1 in humans; Berntson et al, 1993!, and the same relatively linear relationship between autonomic inputs to the heart and heart period~Berntson, Cacioppo, & Quigley, 1995!.…”

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confidence: 99%

Autonomic origins of a nonsignal stimulus‐elicited bradycardia and its habituation in humans

Gianaros

Quigley

2001

Psychophysiology

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The purposes of the present study were to determine the autonomic origins of a bradycardiac response to a moderate intensity nonsignal auditory stimulus and the changes in autonomic cardiac control of this response as a function of habituation. Pure tone stimuli were repeatedly presented to participants while phasic changes in heart period (HP), preejection period (PEP), and respiratory sinus arrhythmia (RSA) were observed. Tone stimuli initially elicited an increase in HP, an increase in RSA, and a decrease in PEP, suggesting a coactivation of the parasympathetic and sympathetic inputs mediating changes in the bradycardiac HP response. As expected, HP responses habituated with repeated presentations of the tones. PEP and RSA responses, however, demonstrated different habituation rates than HP. These data demonstrate that cardiodeceleratory responses to nonsignal stimuli can arise from changes in activity of both autonomic divisions and document the importance of considering the autonomic origins of habituating cardiac responses in order to fully understand the process of response habituation.

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confidence: 99%

Autonomic origins of a nonsignal stimulus‐elicited bradycardia and its habituation in humans

Gianaros

Quigley

2001

Psychophysiology

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“…Autonomic dysfunction may be manifested by decreased short-term variability as seen in hypoxic newborn infants at delivery (15) and in infants of mothers given parasympatholytic drugs (7,8,13,14).…”

Section: Speculationmentioning

confidence: 99%

Relation of Beat-to-Beat Variability to Heart Rate in Normal Sleeping Infants

et al. 1980

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SummaryThe relationship of beat-tebeat heart rate variability (delta RR) and instantaneous heart rate was studied in eight normal infants while asleep during the first four months of life. The sleep state (REM or quiet) was determined using neurophysiologic and behavioral criteria. The results of regression analyses indicated that the delta RR values were positively correlated with the instantaneous heart rate (RR intervals). The correlation coefficient range was 0.49 to 0.92 in quiet sleep and 0.50 to 0.93 in REM sleep. Regression analyses supported-a linear approximation of the delta RR to RR relation over the RR range investigated (400 to 520 msec). The median slope was 0.124 k REM Pad 0.117 in quiet sleep. The slopes of these linear functions were similar in both sleep states and at all ages. If beat-tebeat variability is to be used as an index of the integrity of the autonomic nervous system, these results suggest that delta RR be corrected for RR. A model is presented which relates the demonstrated positive correlation of delta RR to RR with the physiology of cardiac output control. SpeculationThe positive correlation of delta RR with RR is consistent with the view that beat-tebeat heart rate variability is a homeostatic mechanism required for control of cardiac output.Beat-to-beat or short-term heart rate variability (delta RR) is used for identification of fetal distress and is believed to reflect the integrity of the autonomic nervous system in the fetus and newborn (6, 11,18). Autonomic dysfunction may be manifested by decreased short-term variability as seen in hypoxic newborn infants at delivery (15) and in infants of mothers given parasympatholytic drugs (7,8,13,14).Short-term vrcriability may also prove to be a useful parameter for monitoring autonomic function during early infancy. However, as in the fetus (7, 8), short-term variability of the heart rate might be a function of the instantaneous heart rate (instantaneous heart rate defined as the inverse of the RR interval of the electrocardiotrocardiograms done after each study were normal. The procedures and objectives of the study were explained to the parents. and informed consent was obtained. A total of four or five studies, lasting one to two hr, were performed on each infant while it was asleep. Serial studies were performed during the first two wk of life and subsequently at monthly intervals through four months of age. Each study was done in a quiet laboratory environment after a usual midmorning feeding. MEASUREMENT OF THE RR INTERVALSElectrocardiogram surface electrodes were positioned on the chest to obtain a unidirectional polygraph recording with a single prominent R wave which had a sharp peak. Each RR interval of this wide-band electrocardiogram signal (0.5 to 2000 Hz) was measured with an accuracy of 200 p e c using a digital preprocessor designed in this laboratory (17). The data was carefully reviewed, and less than 0.1% of the 10,000 to 15,000 of each study RR intervals were rejected as artifact. SLEEP STAGINGSurface electrodes...

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“…Hon (1958) demonstrated the human error in auscultation in counting the foetal heart rate. The results obtained by 15 observers counting recorded pulses of known rate were shown graphically and the variations seen.…”

Section: Study Of the Foetal Heartmentioning

confidence: 99%

“…Further work in lambs demonstrated that slowly developing hypoxia was followed by tachycardia then bradycardia, acute hypoxia was followed by bradycardia. Hon, Bradfield and Hess '(1961) and Mendez-Bauer, Poseiro, Arrellano-Hernandez, Zambrana and Caldeyro-barcia (1963) studied the vagal factor in foetal bradycardia. Atropine given to the mother relieved mild foetal bradycardia considered to be due to cord compression.…”

Section: Study Of the Foetal Heartmentioning

confidence: 99%

“…Observation of the liquor The significance of meconium staining of the liquor may be difficult to interpret from the point of view of the baby's welfare. Leff (1932) felt that intestinal peristalsis was produced by venous congestion of the bowel, part of a general overloading of the foetal circulation; Hon, Bradfield and Hess (1961) suggested that it was due to vagal stimulation rather a sign of hypoxia. Leonard (1962) surveyed the whole subject and studied 100 cases, concluding that such babies were at risk and would require resuscitation, but only a small fraction would be stillborn.…”

Section: Study Of the Foetal Heartmentioning

confidence: 99%

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