Heart Rate Variability In Children Research Articles

Assessment of heart rate variability in 4–6 years-old children in contrast hardening

The article presents the results of assessing the features of heart rate variability in children of senior preschool age (4-6 years old) who are engaged in contrast hardening according to a specially developed technique (Fisher T.A., Kolyvanova S.S., Dremina E.L., patent RU2744024C2, 9.07.2019) in a preschool educational institution. Significantly higher statistical indicators evaluating the overall autonomic tone (SDNN, RMSSD, рNN50, CV) were revealed in children involved in contrast hardening compared to the control group. Evaluation of statistical, spectral parameters of heart rate variability in the hardening group indicated the predominance of parasympathetic influences on heart rate and a shift in the autonomic balance towards parasympathicotonia. This was expressed in a significant decrease in VPR, an increase in high-frequency (HF) indicators and a decrease in the LF/HF index in children of the hardening group compared with the control.

Heart rate variability in children of younger school age in the speleoclimatotherapy

The autonomic nervous system is a key link in the course of adaptation and adaptive reactions of the organism to various environmental factors. The aim of this study was to assess the heart rate variability of primary school children during a course of speleoclimatotherapy. The heart rate variability were evaluated in 175 practically healthy children aged 7–10 years. In the course of the study the effect of speleoclimatotherapy on the balance sympathetic and parasympathetic nervoussystem was studied using the parameters of spectral analysis of heart rate variability (HRV). HRV data were analysed in the frequency domain: total wave power (TP), high frequency waves (HF), low frequency waves (LF), very low frequency waves (VLF), vagosympathetic index LF/HF. After a course of speleoclimatotherapy the analysis of the obtained results allowed us to establish statistically significant differences in the groups of boy and girls with vagotonic and normotonic type of regulation. After a course of speleoclimatotherapy reduction of the indexe of a vagosympathetic balance (LF/HF) to normal values was found in the groups of sympathotonic boys and sympathotonic girls, while in sympathotonic girls there was an increase in the value of the total power (TP). It is possible to speak about the restoration of vegetative equilibrium and increase of adaptive capabilities of the child’s organism due to adaptation to the microclimate of speleo-chambers.

Can an intervention integrating sports and medicine improve children's health more effectively? Monitoring based on sleep, body mass index, and heart rate variability.

Theoretical studies have suggested that the integration of sports and medicine with one another could positively affect children's health. By monitoring the variation characteristics of children's sleep, body mass index (BMI), and heart rate variability (HRV), we explored and compared the influences of and differences between two interventions - physical exercise and an intervention integrating sports and medicine - on improving children's health. We conducted a randomised controlled study, where we randomly divided 136 children into the physical exercise group (PEG), the integration of sports and medicine group (ISMG), and the control group. We measured sleep, BMI, and HRV at baseline and week eight. After the eight-week intervention, the sleep scores in the PEG and the ISMG were significantly lower than in the control group, while the scores in the ISMG were significantly lower than in the PEG. After the eight-week intervention, the BMI of both the PEG and the ISMG was significantly lower than that of the control group, without a significand difference between the two intervention groups. After the eight-week intervention, the standard deviation of normal-to-normal intervals (SDNN), root mean square differences of the standard deviation (RMSSD), low-frequency of normal (LFn), and high-frequency of normal (HFn) in the PEG and the ISMG were significantly higher than those in the control group, again without a significant difference between the two intervention groups. After intervention, sleep, BMI, and HRV of the three groups were correlated with one another to different degrees, but the correlation coefficient of the two exercise groups was higher. Based on the interventions, we observed a significant correlation between sleep, BMI, and HRV in children. Regular physical exercise or an intervention integrating sports and medicine could synergistically improve sleep, BMI, and HRV in this population, with the latter having a better effect on improving sleep quality.

Assessment of Heart Rate Variability in Children with Mitral Valve Prolapse.

Mitral valve prolapse (MVP) is a heart valve anomaly with specific electrocardiographic findings and arrhythmia. A predominant sympathetic tone and diminished vagal activity have been reported especially in symptomatic MVP patients. In the current study, we aim to review heart rate variability (HRV) parameters of MVP children in order to determine if there is an impaired autonomic regulation. The data of children with MVP were retrospectively analyzed. Demographic characteristics, body mass index, symptomatology, MVP type and mitral regurgitation, MVP-related electrocardiographic changes, arrhythmia, and HRV parameters in 24-h Holter monitoring were recorded. HRV parameters of the control group were obtained from children applying for sport participation. Statistical significance limit was accepted as p < 0.05. 154 of the patients (74.8%) were girls, the median age was 13.58 ± 2.99years. While MVP patients had shorter PR intervals, those who had syncope had longer PR intervals. Short PR distance may be a feature of MVP, long PR distance may be a condition associated with syncope with the underlying paroxysmal atrioventricular block. Moreover, the minimum heart rate was significantly lower in the MVP group compared to the control and there were no significant differences in terms of remaining parameters. The number of low LF values was higher in MVP patients than the control. Comparing HRV values of groups by gender, we found that overall HRV parameters were lower in girls with MVP while minimum, maximum, and average heart rate were lower in boys with MVP. Impaired HRV associated with MVP could be age, gender, and symptom related. In addition, low LF may indicate impaired baroreflex sensitivity in MVP patients.

Evaluation of Heart Rate Variability in Children with Stutter

Evaluation of Heart Rate Variability in Children with Stutter

Feasibility of wearable monitors to detect heart rate variability in children with hand, foot and mouth disease

Hand foot and mouth disease (HFMD) is caused by a variety of enteroviruses, and occurs in large outbreaks in which a small proportion of children deteriorate rapidly with cardiopulmonary failure. Determining which children are likely to deteriorate is difficult and health systems may become overloaded during outbreaks as many children require hospitalization for monitoring. Heart rate variability (HRV) may help distinguish those with more severe diseases but requires simple scalable methods to collect ECG data.We carried out a prospective observational study to examine the feasibility of using wearable devices to measure HRV in 142 children admitted with HFMD at a children’s hospital in Vietnam. ECG data were collected in all children. HRV indices calculated were lower in those with enterovirus A71 associated HFMD compared to those with other viral pathogens.HRV analysis collected from wearable devices is feasible in a low and middle income country (LMIC) and may help classify disease severity in HFMD.

Anthracycline's Effects on Heart Rate Variability in Children with Acute Lymphoblastic Leukemia: Early Toxicity Signs-Pilot Study.

Anthracycline treatments are known to cause cardiotoxic long-term side effects in cancer survivors. Recently, a decrease in heart rate variability (HRV) has been identified in these patients, signaling autonomic dysfunction and altered cardiac fitness. This study aimed at evaluating changes in HRV in children treated with anthracyclines. A total of 35 pediatric patients with acute lymphoblastic leukemia were evaluated by means of a 24 h Holter ECG, at baseline and after reaching half the total cumulative dose of doxorubicin equivalent (120 mg/m2). Parameters of HRV were assessed, as well as any arrhythmic episodes, bradycardia and tachycardia percentages. The results showed a significant decrease in both time-domain and frequency-domain HRV parameters, following anthracycline treatment. The low-frequency (LF) to high-frequency (HF) parameters' ratio also displayed a significant difference (p = 0.035), suggestive of early cardiac autonomic dysfunction. Of note, none of the patients presented symptoms of heart disease or elevated troponins, and only two patients presented echocardiographic signs of diastolic dysfunction. The present study showed that cardiac autonomic nervous system regulation is compromised in children treated with anthracyclines even before reaching the total cumulative dose. Therefore, HRV parameters could be the first indicators of subclinical cardiac toxicity, making Holter ECG monitoring of the oncological patient a necessity.

Preeclampsia-exposed children's heart rate variability 8-12 yr after index pregnancy: FINNCARE study.

Preeclampsia is related with elevated systolic blood pressure (SBP) in children. We studied if preeclampsia-exposed (PE) children develop alterations in heart rate variability (HRV) and if this is reflected in their blood pressure (BP), as well as overall associations with body size and composition, gestational and perinatal factors. We examined 182 PE (46 early-onset PE) and 85 unexposed (non-PE) children 8-12 yr after preeclampsia exposure. HRV monitoring was performed 5 min in supine followed by 5 min in standing position and compared with office, 24-h ambulatory, and central BPs in relation to body anthropometrics and composition, gestational, and perinatal data. There were no major differences in HRV between PE and non-PE children. HRV in supine position was strongly associated with office and ambulatory heart rates (HRs), and HR was independently associated with office BPs. However, HRV was not related with office or 24-h SBP and PP, nor with elevated SBP in PE compared with non-PE children [adjusted mean differences for office and 24-h SBP 4.8 (P < 0.001) and 2.5 mmHg (P = 0.049), respectively]. In supine position, high-frequency (HF) power [β, -0.04 (95% CI -0.06 to -0.01)], root mean square of successive differences in R-R intervals (rMSSD) [-0.015 (-0.028 to -0.002)], and the ratio of low-frequency (LF) to HF power [0.03 (0.01-0.04)] were independently associated with child fat mass. LF and HF power and rMSSD displayed independent inverse associations with child age. There were no significant associations between child HRV and gestational and perinatal factors. During prepuberty, the HRV in children with PE is similar to that in non-PE children. Elevated SBP following preeclampsia exposure is not related with HRV. Child adiposity could be related to decreased cardiac vagal tone.NEW & NOTEWORTHY Heart rate variability in preadolescent children exposed to preeclampsia in utero is no different from age-matched controls. Preeclampsia-exposed children's elevated SBP is not related to alterations in heart rate variability, which is a noninvasive measure of the modulation of heart rate by autonomic tone. However, childhood adiposity might be coupled with diminished cardiac vagal tone.

Association between Val158Met polymorphism in the COMT gene with anxiety and heart rate variability in children with irritable bowel syndrome

The aim of this study was to examine the peculiarities of trait anxiety and heart rate variability parameters as well as their relationship depending on the catechol O-methyltransferase (COMT) gene Val158Met polymorphism in children with irritable bowel syndrome. Materials and methods. A total of 26 children aged 6–12 years with a verified diagnosis of irritable bowel syndrome according to the Rome IV criteria were examined. Beforehand, all the patients underwent molecular genetic testing for the COMT Val158met single nucleotide polymorphism by using the polymerase chain reaction-restriction fragment length polymorphism method. Heart rate variability was analyzed via cardiointervalography (Neurosoft) based on short five-minute resting-state ECG recordings. The CMAS (Children’s Manifest Anxiety Scale) test was used to measure trait anxiety levels. The Pearson’s test was used to assess correlations between heart rate variability parameters and anxiety levels. Data were processed using Microsoft Excel 2016 and analyzed with GraphPad (Prism 5.0). Results. Depending on the functional COMT Val158met polymorphism, all the patients were allocated to 3 groups: 8 children with 472 GA (Val/Met) COMT genotype; 10 children with 472 AA (Met/Met) genotype; 8 children with 472 GG (Val/Val) genotype. Time and frequency domain parameters of heart rate variability were significantly different in each group. The highest level of anxiety and the largest percentage of LF component (mainly sympathetic activity) in the structure of heart rate variability was noted among Met/Met carriers. Val/Val carriers had a significantly lower anxiety level and an autonomic imbalance with a higher percentage of HF component (parasympathetic activity). Positive correlations between trait anxiety and heart rate variability parameters were found only in Val/Val and Val/Met groups. Conclusions. Our study has revealed the influence of the COMT Val158met polymorphism on the level of trait anxiety and heart rate variability parameters. It is important for a better understanding of the gut-brain axis dysregulation and impaired stress resilience in children with irritable bowel syndrome. Also, these data could be used to improve current schemes for the treatment of irritable bowel syndrome, supplementing them with activation therapy, psychotherapy, psychopharmacotherapy.

Decreased Heart Rate Variability in Children with Acute Decompensated Heart Failure is Associated with Poor Outcomes.

Heart rate variability (HRV) is a noninvasive indicator of the health of neurocardiac interactions of the autonomic nervous system. In adults, decreased HRV correlates with increased cardiovascular mortality. However, the relationship between HRV and outcomes in children with acute decompensated heart failure (ADHF) has not been described. Patients < 21years old hospitalized with ADHF from 2013 to 2019 were included (N = 79). Primary outcome was defined as death, heart transplant, or mechanical circulatory support (MCS). The median standard deviation of the R-to-R interval in 5-min intervals (SDNN) was calculated from telemetry data obtained across the first 24h of admission. Patients who met the primary outcome had significantly lower median SDNN (13.8 [7.8, 29.1]) compared to those who did not (24.6 [15.3, 84.4]; p = 0.004). A median SDNN of 20ms resulted in a sensitivity of 68% and specificity of 69%. Median SDNN < 20ms represented decreased freedom from primary outcome (p = 0.043) and a hazard ratio of 2.2 in multivariate analysis (p = 0.016). Pediatric patients with ADHF who died, underwent heart transplant, or required MCS had significantly decreased HRV at presentation compared to those that did not. This supports HRV as a noninvasive tool to improve prognostication in children in ADHF.

Group Changes in Cortisol and Heart Rate Variability of Children with Down Syndrome and Children with Autism Spectrum Disorder during Dog-Assisted Therapy.

Dog-assisted therapy is hypothesized to lower stress in children with autism spectrum disorder (ASD) and children with Down syndrome (DS), which may be visible on a physiological level. In this study, we measured heart rate variability (HRV) and salivary cortisol of 20 children with DS or ASD at the beginning and end of six weekly sessions of dog-assisted therapy. We found a decrease of cortisol levels during single sessions, but no overall effect after six sessions (six weeks). The effect of dog-assisted therapy on the increase of HRV could not be confirmed. This study is one of the first to use physiological measurements to test the effects of DAT.

Sleep disordered breathing improvement prevents worsening of autonomic dysfunction in children with Down syndrome

BackgroundResolution of sleep disordered breathing (SDB) in typically developing children normalises heart rate variability (HRV), a measure of autonomic control, to that of non-snoring controls. Children with Down Syndrome (DS) have dampened heart rate variability (HRV) but the effect of treatment is not known. To assess the effect of improvement of SDB on autonomic control we compared HRV in children with DS whose SDB improved over 2 y, to those whose SDB did not improve. Methods24 children (3–19 y) had a baseline and follow-up polysomnographic study 2 y later. Improved SDB was defined as a reduction in obstructive apnea hypopnea index (OAHI) to ≤ 50% of baseline. Children were grouped into Improved (n = 12) and Unimproved (n = 12). Power spectral analysis of the ECG determined low frequency (LF), high frequency (HF) power and the LF/HF ratio. Seven children in the Improved and 2 in the Unimproved group were treated following the baseline study. ResultsIn the Unimproved group at follow-up, LF power was lower compared to baseline during N3 and Total Sleep (p < 0.05 for both). HF power was lower during REM (p < 0.05). HRV remained unchanged between studies in the Improved group. ConclusionAutonomic control worsened as indicated by lower LF and HF power in children whose SDB was not improved. In contrast, in those children with improved SDB, autonomic control remained the same, suggesting improvement in SDB severity prevents further worsening of autonomic control in children with DS.

Reactivity of the autonomic nervous system in children of younger school age with mental retardation

Introduction. The functioning of the autonomic nervous system (ANS) to some extent affects various aspects of human health and general well-being. One of the main ANS functions is to ensure adaptation to the factors of the external and internal environment, carried out by the coordinated activity of the sympathetic and parasympathetic links. Determining the predominant type of ANS reactivity according to the characteristics of the heart rhythm makes it possible to predict the adaptive capabilities of the child’s body in the learning process in a personalized way. &#x0D; The aim of the study was to study the trend in heart rate variability in children with special health conditions associated with disorders of the intellectual development, which characterizes the implementation of mechanisms for adapting the body to the conditions of schooling.&#x0D; Materials and methods. We examined one hundred sixty eight 7–11 years children of primary school age, including 54 children with special health abilities (SHA) (F70, F71), and 114 mentally healthy children. The study of heart rate variability was carried out using the hardware-software complex “ORTO Valeo”. There was analyzed TP, HF, LF, VLF, LF / HF; RMSSD, SDNN, Mo, AMo, ΔX, IN, AMo / Mo, Amo / ΔX; type of vegetative regulation.&#x0D; Results. In SHA children of primary school age, the LF, VLF, LF / HF indices are increased and HF is decreased relative to the control group, which indicates the predominance of the sympathetic link of the autonomic nervous system over the parasympathetic. When analyzing the spectral components in SHA children of primary school age, VLF (40.6%) and low HF (19.6%) dominate. According to the types of autonomic regulation in SHA children, the following ratio was found 50: 4: 33: 13, the central type of cardiac regulation dominates (type I).&#x0D; Limitations. The limitation of the study is due to the specifics of the individuals in the observation group – children of primary school age (7–11 years) with special health opportunities associated with mental retardation.&#x0D; Conclusion. SHA children of primary school age have high activity of sympathetic modulation, reduced resistance to stress, high tension of adaptive responses with the dominance of the central type of regulation of the cardiac activity. The revealed imbalance of the parameters of autonomic regulation in SHA children without corrective measures (including correction of physical status, psychoemotional and educational loads) threatens the development of a breakdown of adaptive responses to the effects of various internal and external factors, contributing to asthenization of regulatory systems.

Impact of asthma on heart rate variability in children and adolescents: Systematic review and meta-analysis.

Asthma is associated with abnormal autonomic function, and heart rate variability is considered a simple, accurate, and noninvasive tool for monitoring the autonomic system. Thus, the aim of this study was to investigate the impact of asthma on heart rate variability in children and adolescents. This systematic review of observational studies and clinical trials evaluated heart rate variability in children and adolescents with asthma compared to healthy controls. The data were extracted independently by two reviewers. The quality of the selected articles was assessed using Agency for Health Care Research and Quality indicators. Random effects meta-analysis was performed for each outcome, with the effect size reported as standardized mean difference. Fifteen studies were included, of which five were classified as having high methodological quality. In the meta-analysis, long-term recording of the standard deviation of all normal-to-normal sinus R-R intervals differed significantly between groups (standardized mean difference [SMD] = -0.46 [95% confidence interval {CI}: -0.79 to -0.14], p < 0.005, I2 = 0%). Moreover, R-R intervals (long-term) were significantly shorter in asthmatic children than controls (SMD = -0.47 [95% CI: -0.68 to -0.25], p < 0.0001, I2 = 0). There were no significant differences between adjacent normal R-R intervals that exceed 50 ms (long-term) and the root mean square of successive differences between normal sinus R-R intervals (short-term). Regarding frequency-domain variables, long-term low frequency measurements differed significantly between groups (SMD = -0.34 [95% CI: -0.58 to -0.10], p < 0.005, I2 = 15%). There were no differences in high frequency measurements or in the ratio between low/high frequency powers (short- or long-term) between groups. The results confirm the impact of asthma on heart rate variability in children and adolescents, indicating lower heart rate variability and sympathetic modulation.

Heart Rate Variability in Children with Moderate and Severe Traumatic Brain Injury: A Prospective Observational Study

AbstractThe aim of this study was to assess the feasibility of continuous monitoring of heart rate variability (HRV) in children with traumatic brain injury (TBI) hospitalized in a pediatric intensive care unit (PICU) and collect preliminary data on the association between HRV, neurological outcome, and complications. This is a prospective observational cohort study in a tertiary academic PICU. Children admitted to the PICU ≤24 hours after moderate or severe TBI were included in the study. Children suspected of being brain dead at PICU entry or with a pacemaker were excluded. Children underwent continuous monitoring of electrocardiographic (ECG) waveforms over 7 days post-TBI. HRV analysis was performed retrospectively, using a standardized, validated HRV analysis software (CIMVA). The occurrence of medical complications (“event”: intracranial hypertension, cerebral hypoperfusion, seizure, and cardiac arrest) was prospectively documented. Outcome of children 6 months post-TBI was assessed using the Glasgow Outcome Scale – Extended Pediatric (GOS-E Peds). Fifteen patients were included over a 20-month period. Thirteen patients had ECG recordings available and 4 had &gt;20% of missing ECG data. When ECG was available, HRV calculation was feasible (average 88%; range 70–97%). Significant decrease in overall HRV coefficient of variation and Poincaré SD2 (p &lt; 0.05) at 6 hours post–PICU admission was associated with an unfavorable outcome (defined as GOS-E Peds ≥ 3, or a deterioration of ≥2 points over baseline score). Several HRV metrics exhibited significant and nonsignificant variation in HRV during event. This study demonstrates that it is feasible to monitor HRV in the PICU provided ECG data are available; however, missing ECG data are not uncommon. These preliminary data suggest that altered HRV is associated with unfavorable neurological outcome and in-hospital medical complications. Larger prospective studies are needed to confirm these findings and to explore if HRV offers reliable and clinically useful prediction data that may help clinical decision making.

Relation of Young Children's Parasympathetic Reactivity During a Learning Task to Their Self‐Regulation and Early Academic Skills

AbstractThere is growing interest among educational researchers in using heart rate variability (HRV) as an index of children's capacity to regulate their physiological arousal. Links between HRV and young children's self‐regulation have, however, been inconsistent, and there is limited research on children's HRV in learning‐related contexts. HRV was collected from 86 children aged 3.41 to 5.83 years before, during, and after they engaged in a learning interaction with an examiner. Higher HRV during a pre‐learning episode and a larger drop in HRV during the learning interaction were associated with stronger behavioral performance on self‐regulation and early academic skill assessments. Children's capacity to modulate their HRV in response to learning opportunities may be linked to their broader self‐regulation and early academic skill development. Effects varied by episode and gender, underscoring a need for further research to rigorously evaluate the utility and generalizability of HRV in authentic educational settings.

Heart rate variability in children: methodological issues and clinical applications

Heart rate variability (HRV) corresponds to variations in heart rate or beat-beat time interval. This parameter reflects the status of the autonomic mechanisms of cardiovascular control, which may be influenced by changes characteristic of the life cycle of people, sedentary lifestyle, and various disease processes that directly or indirectly generate changes in the HRV and shift the autonomic balance, either towards greater sympathetic or parasympathetic influence on the heart. These antecedents support the use of HRV indices for the diagnosis and monitoring of various nosological entities in adults. However, there has been limited progress in the study of temporal variations in heart rhythm in the pediatric population. This article aims to describe the physiological and technical aspects of HRV in the pediatric population to provide a background that allows optimizing the application of these parameters in this age group.La variabilidad del ritmo cardíaco (VRC) corresponde a las variaciones temporales de la frecuencia cardíaca o del intervalo latido-latido. Este parámetro refleja el estado de los mecanismos autonómicos de control cardiovascular. Los cambios propios del ciclo vital de las personas, el sedentarismo y diversos procesos de enfermedad han mostrado inducir cambios en la VRC y desplazar el balance autonómico hacia una mayor influencia simpática o parasimpática sobre el corazón. Estos antecedentes apoyan el uso de los índices de VRC para el diagnóstico y seguimiento de diversas entidades nosológicas en el adulto. Sin embargo, en la población pediátrica ha existido un limitado avance en el estudio de las variaciones temporales del ritmo cardíaco. Este artículo tiene por objetivo describir los aspectos fisiológicos y técnicos de la VRC en población pediátrica. El propósito es aportar antecedentes que permitan optimizar la aplicación de estos parámetros en este grupo etario.

Evaluation of Heart Rate Variability in Children with Congenital Heart Diseases before and after Surgical Repair

Background: Surgical repair of congenital heart diseases (CHD) affects heart rate variability (HRV) in different ways. It leads to varying degrees of cardiac autonomic derangement, clinically detectable as depression of HRV parameters. The aim of this work was to evaluate HRV in children with CHDs before and after surgical repair to detect the effect of CHDs (acyanotic or cyanotic) and cardiac surgery on cardiac autonomic function.&#x0D; Methods: This observational case-control study enrolled thirty cases with CHD. Cases were divided in two equal groups: group1 included children with CHDs (not repaired) before surgical intervention and group 2 included children after surgical repair of CHDs. Another fifteen healthy children, matched for age and sex, were enrolled as a control group. All children in this study were subjected to full history taking, clinical evaluation, Holter monitor, twenty-four-hour ambulatory electrocardiographic recordings and the seven time-domain indices of HRV.&#x0D; Results: There was significant increase of HR in patients before surgical repair as compared to patients after surgical repair as compared to control group. There was significant decrease of PNN50, r MMSD, SDNN index and SDANN of children before surgical repair as compared to children after surgical repair as compared to controls. There was a negative significant correlation between HR and age before surgery, after surgery there was a negative significant correlation between HR and age, pNN50, rMMSD, SDNN index and SDANN, in control there was negative significant correlation with age, SDNN index, SDANN and SDNN.&#x0D; Conclusion: HRV parameters increased significantly in children with CHDs after surgical repair as compared to these before surgical repair denoting effect of cardiac surgery on cardiac autonomic function.

O034 Autonomic control of heart rate stabilises with improvement of sleep disordered breathing in children with Down syndrome

Abstract Background Sleep disordered breathing (SDB) alters autonomic function, assessed using heart rate variability (HRV) in typically developing (TD) and children with Down syndrome (DS). SDB resolution in TD children normalises HRV, but the effects in children with DS are unknown. We compared HRV in children with DS with improved SDB (decrease in obstructive apnoea hypopnoea index (OAHI) to ≤ 50% of baseline OAHI) to those with unimproved SDB 2 y following baseline study. Methods 24 children (3-19 y at baseline) were included. Power spectral analysis of the ECG determined low frequency (LF, parasympathetic and sympathetic activity), high frequency (HF, parasympathetic activity) power and LF/HF (sympathovagal balance). Children were grouped into Improved (n=12; 7 treated between studies) and Unimproved (n=12; 2 treated between studies). Results OAHI decreased between studies in the Improved group (baseline, 29.5 (1.6,154.0) [mean (min,max)] events/h; follow-up, 8.4 (0,77.0); p&amp;lt;0.05), and worsened in the Unimproved group (baseline 6.1 (0,22.9); follow-up 14.4 (0.3, 54.6); p&amp;lt;0.05). LF power was lower at follow-up in the Unimproved group compared to baseline during Total Sleep (p&amp;lt;0.05), N3 (p&amp;lt;0.05) and REM (p&amp;lt;0.01). HF power was also lower at follow-up in the Unimproved group during REM (p&amp;lt;0.05). HRV remained unchanged between baseline and follow-up for the Improved group. Conclusion Autonomic control worsened as indicated by lower sympathetic and parasympathetic activity in children whose SDB was not improved. In contrast, in those children with improved SDB autonomic control remained the same, suggesting improvement in SDB severity prevents further worsening of autonomic control in children with DS.

ВАРИАБЕЛЬНОСТЬ РИТМА СЕРДЦА У ДЕТЕЙ С ДЕФЕКТОМ МЕЖЖЕЛУДОЧКОВОЙ ПЕРЕГОРОДКИ

The aim of the study was to assess heart rate variability in children with a ventricular septal defect (VSD). Material and methods: Holter monitoring was performed in patients with ventricular septal defect from 3 to 18 years of age with an assessment of the temporal and spectral parameters of heart rate variability. Conclusion: in children with VSD, a decrease in the parameters of the temporal analysis of heart rate variability compared with healthy peers (p &lt;0.05) was observed, more pronounced in patients with operative correction of the defect, as well as an increase in the low-frequency spectrum power (LF) as an indicator of amplification sympathetic effects on heart rate. A statistically significant correlation was found between the SDNN, SDANNi parameters and the pressure levels in the right ventricle and pulmonary artery (ρ = 0.5, p &lt;0.01) in the group of patients with benign VSD without operative correction of the defect. The decrease in indicators of the temporal parameters of heart rate variability was inversely correlated with an increase in the postoperative period. Conclusions: in children who underwent surgical closure of the VSD, there was a disturbed heart rate variability, which had an inverse correlation with the duration of the postoperative period