Analysis of Heart Rate and Respiratory Patterns in Sudden Infant Death Syndrome Victims and Control Infants

Abstract

ABSTRACT. Retrospective analyses of patterns of breathing and heart rate variability obtained by visual inspection and spectral analysis of ECG and respiratory activity have provided markers associated with subsequent death in a referred population of infants at high risk for sudden infant death syndrome (SIDS). Such markers include breathing patterns characterized by excessive apneic pauses and periodic breathing, heart rate spectra characterized by increased low frequency oscillations, and respiratory activity spectra characterized by a widened "bandwidth" during regular breathing. To test whether such measurements could distinguish SIDS cases and randomly selected controls from a population study the data from 10 cases and 100 age-matched control subjects were analyzed blind. The code was disclosed after completion of the analysis. We found that none of the markers served to distinguish the SIDS cases from the controls in the population at large. This observation may indicate important physiological differences between infants destined to die in the referred high risk population and infants who die of SIDS at large. The possible reasons for our inability to identify the group of SIDS in the general population, as compared to the group of deaths in the referred high risk group are: (1) different disease processes in the two groups, (2) difference responses to the same disease process in the two groups, (3) a response reflecting the psychosocial setting of the referred high risk population, (4) methodological differences between this and previous studies. We conclude that these markers are not of value in screening the population at large. (Pediatr Res 20: 680-684, 1986) Abbreviations HR, heart rate SIDS, sudden infant death syndrome Received August 14, 195; accepted February 18, 1986. Correspondence Dr. D. Gordon, Pediatric Cardiology, University of Illinois at Chicago, University of Illinois Hospital Box 6998, Chicago, IL 60680.Supported by the Reynolds Foundation, the Healthdyne Company, MESCO, the McGraw Foundation, the National Foundation for Sudden Infant Death, PhysioParameters, Inc., the Scholl Foundation, NSF Grant ECS8 12 157 1, Office of Naval Research Grant N00014-80-C-0520, USAF School of Aerospace Medicine Award F33615-84-C-0601, and NASA Grant NAG2-327. JMR was supported by the U.K. Foundation for the Study of Infant Death and DPS was supported by the British Heart Foundation.Several patterns of breathing and heart rate variation have been identified in infants referred for evaluation for high risk of SIDS which appear to distinguish them from infants not at risk ( 1-3). High levels of periodic breathing and apneic pauses ( 1, 3, 4) have been identified by visual inspection of respiratory activity recordings in the high risk infant referred for evaluation. Power spectrum analysis demonstrated two spectral variables that were increased in referred high risk babies who subsequently died suddenly, unexpectedly, and without explanation (2): the power of oscillation in heart rate with a period of a...

Normal Ranges of Heart Rate Variability During Infancy and Childhood

“…This correlation had been described in newborns [3,6,26,32], in infants [2,10,14,16,31], and in schoolchildren and young adults [8,10,37]. Southall and coworkers analyzed changes of heart rate variability during infancy, which is a period of rapid sympathetic nervous system development, and demonstrated a delayed or deficient cardiovagal development in infants who subsequently succumbed to the sudden infant death syndrome [2,14,31].…”

“…Since the first report on the use of heart rate variability parameters in 1978 [35], impaired variability was found in adult patients with myocardial infarction [18,21], left ventricular dysfunction [23,34], low cardiac output [17], chronic heart failure [23,28,33], panic disorder [36], and diabetic neuropathy [7]. A few reports are available in the pediatric literature on the heart rate behavior in premature infants [6,27], newborns [6,32], full-term infants at risk for sudden infant death syndrome [2,14,16,25,31], normal infants and children [10], diabetic children [1,20,22,38,39], children with atrial septal defect [9], and critically ill children following cardiac surgery [15]. Most of these reports compared a group of ill children with age-matched healthy children, so that well-documented normal ranges of heart rate variability for most parameters, to assess the behavior of the autonomic function during infancy and childhood, are not yet available.…”

Cardiorespiratory Patterns in Infants Presenting with Apparent Life-Threatening Episodes

“…It is quite possible that the lower respiratory rates and increased numbers of short ap noeic pauses are linked, as previously dis cussed by Richards et al [7], The higher inci dence of periodic breathing patterns in the ALE cases may also be relevant to the excess of low frequency heart rate oscillation identi fied by Gordon et al [13] in their study of 'near-miss' patients who subsequently died. This excess low frequency heart rate oscilla tion was not increased in infants from a pop ulation who had not suffered from ALE, but who became victims of SIDS [14]. It is also important to recall that, in our previous study comparing recordings made on infants who became victims of SIDS with those of surviving controls, no significant differences in numbers of short apnoeic pauses, quanti ties of periodic breathing or respiratory rates during regular breathing were identified [6], Although these respiratory variables are ab normally represented in ALE cases, this find ing does not necessarily indicate that these abnormal measurements are related to pro longed apnoeic pauses or to SIDS.…”

Retarded heart growth in the victims of sudden infant death: possible implications for lethal mechanisms

“…At the same time, little is known about organ growth capacity in the SID babies, although retarded somatic growth may bring with it retarded organ development, which in turn may predispose to functional disturbances. Of special interest seems to be the growth pattern of the heart since there is increasing evidence for possible involvement of cardiac mechanisms in some SID cases [8,19,22,26].…”