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OBJECTIVE: Numerous restrictions, which are imposed on children with arrhythmia, influence their quality of life (QoL) and may have a negative impact on their further development. Ablation is a highly successful treatment leaving patients free from arrhythmia and other related limitations. There are very few studies evaluating the influence of ablation on the QoL in children with arrhythmia, based on small groups of patients. The aim of this study was to evaluate the impact of ablation on the QoL in children with supraventricular tachycardia (SVT). PATIENTS AND METHODS: We included 122 children with SVT who underwent a successful ablation. The Qol was assessed before and after the ablation, using the WHOQOL-BREF and the Pediatric Arrhythmia Related Score (PARS) -- a specific questionnaire developed by the authors. RESULTS: Six months after the ablation, WHOQOL- BREF showed a significant improvement in the QoL in the physical (Phd) (p < 0.0001), psychological (Psd) (p = 0.0014) and social relationships (SRD) (p = 0.0165) domains. PARS showed a significant improvement in the QoL in the Phd (p < 0.0001), Psd (p = 0 .0307) a nd m edical s atisfaction domains (Msd) (p < 0 .0001). N o i mprovement in Psd was revealed in children who had been off medications before the ablation. In the youngest children, a significant improvement was observed in all the measured domains in both questionnaires (p < 0 .05), w hile i n o lder children the greatest improvement after the ablation was noted in the area of physical functioning. CONCLUSIONS: Ablation in children with SVT significantly improved general satisfaction with health and with the QoL and had a positive impact on QoL scores. The youngest patients and those on antiarrhythmic medication before the ablation, benefit most from the procedure. [ABSTRACT FROM AUTHOR]

Abstract Background The 22q11.2 microdeletion syndrome (22q11.2 deletion syndrome -22q11.2DS) refers to congenital abnormalities, including primarily heart defects and facial dysmorphy, thymic hypoplasia, cleft palate and hypocalcaemia. Microdeletion within chromosomal region 22q11.2 constitutes the molecular basis of this syndrome. The 22q11.2 microdeletion syndrome occurs in 1/4000 births. The aim of this study was to determine the frequency of 22q11.2 microdeletion in 87 children suffering from a congenital heart defect (conotruncal or non-conotruncal) coexisting with at least one additional 22q11.2DS feature and to carry out 22q11.2 microdeletion testing of the deleted children's parents. We also attempted to identify the most frequent heart defects in both groups and phenotypic traits of patients with microdeletion to determine selection criteria for at risk patients. Methods The analysis of microdeletions was conducted using fluorescence in situ hybridization (FISH) on metaphase chromosomes and interphase nuclei isolated from venous peripheral blood cultures. A molecular probe (Tuple) specific to the HIRA (TUPLE1, DGCR1) region at 22q11 was used for the hybridisation. Results Microdeletions of 22q11.2 region were detected in 13 children with a congenital heart defect (14.94% of the examined group). Microdeletion of 22q11.2 occurred in 20% and 11.54% of the conotruncal and non-conotruncal groups respectively. Tetralogy of Fallot was the most frequent heart defect in the first group of children with 22q11.2 microdeletion, while ventricular septal defect and atrial septal defect/ventricular septal defect were most frequent in the second group. The microdeletion was also detected in one of the parents of the deleted child (6.25%) without congenital heart defect, but with slight dysmorphism. In the remaining children, 22q11.2 microdeletion originated de novo. Conclusions Patients with 22q11.2DS exhibit wide spectrum of phenotypic characteristics, ranging from discreet to quite strong. The deletion was inherited by one child. Our study suggests that screening for 22q11.2 microdeletion should be performed in children with conotruncal and non-conotruncal heart defects and with at least one typical feature of 22q11.2DS as well as in the deleted children's parents.

Purpose: Mitral valve surgery in children involves correcting congenital and acquired pathologies, with a reported mortality rate of 0.9%. Low cardiac output syndrome (LCOS) is a serious complication with the incidence of 20-25%. The aim of the study was to estimate possible prognostic factors of LCOS in children undergoing mitral valve procedure., Material and Method: This single-center retrospective analysis enrolled children aged <18 years who underwent mitral valve surgery during 24 year period. Preoperative clinical and laboratory parameters, and operative factors were analyzed., Results: Thirty consecutive pediatric patients (11 (37%) males and 19 (63%) females) in median (Q 1 - Q 3 ) age of 57 (25-115) months, who underwent mitral valve replacement, were included. The 30-day mortality was 7% (2 patients) and was related to postoperative multiorgan failure. LCOS occurred in 8 (27%) children. The receiver operator curve (ROC) analysis established parameters that have predictive value for LCOS occurrence: cardiopulmonary bypass (CPB) time, with 89 ​min as optimal cut-off point (AUC ​= ​0.744, p ​= ​0.011) yielding sensitivity of 100% and specificity of 42.9%; left ventricular ejection fraction (LVEF) ​< ​60 % (AUC ​= ​0.824, okp ​= ​0.001) with sensitivity of 62.5% and specificity of 93.75%; and red blood cell distribution width (RDW) above 14.5 % (AUC ​= ​0.840, p ​< ​0.001; sensitivity of 87.5% and specificity of 75%)., Conclusions: In mitral valve replacement in pediatric patients, CPBtime above 89 ​min, preoperative LVEF below 60% and preoperative RDW above 14.5% can be regarded as the potential predictors of LCOS., Competing Interests: Declaration of competing interest The authors declare no conflict of interests., (Copyright © 2024. Published by Elsevier B.V.)

Background: To our knowledge, no studies have assessed quality of life (QoL) in asymptomatic children with a preexcitation electrocardiogram pattern., Aim: To evaluate the QoL of children with asymptomatic Wolff-Parkinson-White (WPW) syndrome., Methods: This study involved QoL assessment of 31 children with asymptomatic preexcitation and 82 healthy children using the WHOQOL-BREF and the Pediatric Arrhythmia Related Score (PARS), a specific questionnaire that we have developed, which is related to patients' feelings and observations concerning arrhythmia., Results: There were no significant differences between the two groups in all the measured domains; however, there were significant differences regarding general satisfaction with their health condition (P = 0.01). There were no differences in general satisfaction with the QoL, but WPW children more often experienced palpitations than the control group (P <0.001) and were more likely to feel sad (P = 0.046) and nervous (P = 0.04) compared to healthy children., Conclusions: The children with WPW were more dissatisfied with their health compared to healthy children. Although both groups of children had similar levels of satisfaction with their QoL, some areas of physical and psychological parameters of QoL were worse in WPW children. The PARS questionnaire is a useful tool as a disease-specific QoL instrument, which supplements the general questionnaire and aids in clinical practice and decision-making.

Background: Remote monitoring (RM) of cardiac implantable electronic devices for adults offers improved treatment efficacy and, consequently, better patient clinical outcomes. There is scant data on the value and prognosis of RM in the pediatric population., Aims: The goal of this study was to determine the efficacy of RM by analyzing the connectivity of bedside transmitters, adherence to planned automatic follow-ups, and occurrence of alert-based events., Methods: We evaluated the pediatric population with implanted pacemakers for congenital AV block or after surgically corrected congenital heart diseases., Results: A total of 69 patients were included in our study. The median (Q1-Q3) patient age was 6.0 (2.0-11.0) years. All patients received bedside transmitters and were enrolled in the RM system. Among them, 95.7% of patients had their first scheduled follow-up successfully sent. Patients were followed up remotely over a median time of 33.0 (13-45) months. Only 42% of patients were continuously monitored, and all scheduled transmissions were delivered on time. Further analysis revealed that 34.8% of patients missed transmissions between June and September (holiday season). Alert-based events were observed in 40.6% patients, mainly related to epicardial lead malfunction and arrhythmic events. Overall compliance was also compromised by socioeconomic factors., Conclusions: Our findings are in concordance with recently published results by PACES regarding a high level of compliance in patient enrollment to RM and time to initial transmission. However, a lower level of adherence was observed during the holiday season due to interrupted connectivity of bedside transmitters. Importantly, a relatively low occurrence of alert transmissions was observed, mainly related to epicardial lead malfunction and arrhythmic events.

Pulmonary arterial hypertension (PAH) is a rare heterogeneous disorder in the paediatric population which is mostly associated with congenital heart disease. The management of paediatric idiopathic PAH (IPAH) is difficult due to insufficient comparative data and depends on the results of evidence-based adult studies with several pulmonary vasodilators, as well as the clinical experiences of paediatric experts. Our aim was to present the case of a 9-year-old girl who underwent several methods of treatment, including pharmacotherapy with a significant reaction to treprostinil, as well as bilateral lung transplantation. The patient's treatment was distinguished by the fact that the dose escalation was as rapid as that observed in the adult population. Due to the limited current evidence and knowledge, the initiation of treatment for these patients remains an individual choice. On the grounds of the number of non-specific symptoms, the diagnosis of this patient was a long process and based mainly on the differential diagnosis. The purpose of this paper is to study this example in order to highlight the importance of early symptoms and the quick implementation of intensive treatment. The applied methods may be useful in doubtful diagnosis processes and treatment procedures in the paediatric population.

Simple whole blood analysis can effectively demonstrate complex changes in inflammatory responses to cardiovascular disorders in adults and enable the prediction of adverse outcomes or diminished survival. Such inflammatory activation has also been detected in the pediatric population. Blood analysis results are repeatable and readily available, which gives the method an advantage over others. Inflammatory phenomena such as a high leukocyte count and an increased neutrophil-to-lymphocyte ratio (NLR) are related to a poor prognosis of advanced heart defects and worse outcomes after pediatric cardiac surgery in the advanced stages of the disease. Surgery-associated inflammation exacerbates these diseases, and the inflammatory response may further complicate the postoperative period. Simple blood cell counts and indices may be beneficial for evaluating cardiac surgery outcomes and cardiovascular disorder prognosis in infants and children. This review summarizes current knowledge on inflammatory markers in pediatric cardiovascular diseases and surgery.

Competing Interests: The authors declare no conflict of interest.

Heart rate asymmetry (HRA) is a physiological phenomenon characterized by an unequal contribution of heart rate decelerations and accelerations to different heart rate variability (HRV) features. While HRA has been demonstrated in adults' ECGs of different duration, a similar investigation in healthy children has not been conducted. This study investigated the variance- and number-based HRA features in 96 healthy children (50 girls and 46 boys, aged 3-18 years) using 24-h ECGs. Additionally, we studied sex differences in HRA. To quantify HRA, variance-based and relative contributions of heart rate decelerations to short-term (C1d), long-term (C2d), and total (CTd) HRV, and the number of all heartbeats (Nd) were computed. Heart rate decelerations contributed more to C1d, but less to C2d and CTd, and were less frequent than heart rate accelerations. Short-term HRA was better expressed in boys. The majority of children (93.7%) had short-term HRA, 88.5% had long-term HRA, 88.5% had total HRA, and 99.0% had more accelerations than decelerations. No sex differences were observed for the rate of various HRA features. Heart rate asymmetry is a common phenomenon in healthy children, as observed in 24-h ECGs. Our findings can be used as reference data for future clinical studies on HRA in children.

Neutrophils play a significant role in immune and inflammatory reactions. The preoperative inflammatory activation may have a detrimental effect on postoperative outcomes. The aim of the study was to investigate the relation between preoperative hematological indices on postoperative complications’ risk in pediatric cardiac congenital surgery. The retrospective single center analysis included 93 pediatric patients (48 (65%) males and 45 (35%) females), mean age of 7 (3−30) months referred for cardiac surgery in cardiopulmonary bypass due to functional single ventricle disease (26 procedures), shunts lesions (40 procedures) and cyanotic disease (27 procedures). Among simple hematological indices, the receiver-operating-characteristic curve showed that a neutrophil count below 2.59 K/uL was found as an optimal cut-off point for predicting postoperative atrioventricular block following pediatric cardiac surgery (AUC = 0.845, p < 0.0001) yielding a sensitivity of 100% and a specificity of 65.62%. Preoperative values of neutrophil count below 2.59 K/uL in whole blood analysis can be regarded as a predictive factor (AUC = 0.845, p < 0.0001) for postoperative atrioventricular block in pediatric cardiac surgery.

The COVID-19 pandemic has impacted healthcare systems worldwide. Little is known about the impact of the pandemic on medical and psycho-social aspects of children with rare diseases such as pulmonary arterial hypertension and their parents. The study is based on children registered in The Database of Pulmonary Hypertension in the Polish Population and a parent-reported survey deployed during the first 6 months of the pandemic. The questionnaire consisted of six question panels: demographic data, fear of COVID-19, General Anxiety Disorder-7 (GAD-7), social impact of pandemic, patients' medical status, and alarming symptoms (appearance or exacerbation). Out of 80 children registered, we collected 58 responses (72.5% response rate). Responders (parents) were mostly female ( n = 55; 94.8%) at a mean age of 40.6 ± 6.9 years. Patients (children) were both females ( n = 32; 55%) and males with a mean age of 10.0 ± 5.1 years. Eleven (19%) children had symptoms of potential disease exacerbation. Eight parents (72.7%) decided for watchful waiting while others contacted their GPs or cardiologists ( n = 6; 54.5%). Three children had to be hospitalized (27.3%). Most planned hospitalizations (27/48; 56.2%) and out-patient visits (20/35; 57.1%) were cancelled, delayed, or substituted by telehealth services. Among the participating parents, the study shows very high levels of anxiety ( n = 20; 34.5%) and concern ( n = 55; 94.8%) and the need for detailed information (52; 89.6%) regarding COVID-19 and medical service preparedness during the pandemic. The COVID-19 pandemic has influenced child healthcare and caused high levels of anxiety among parents.

We present the results from the pediatric arm of the Polish Registry of Pulmonary Hypertension. We prospectively enrolled all pulmonary arterial hypertension (PAH) patients, between the ages of 3 months and 18 years, who had been under the care of each PAH center in Poland between 1 March 2018 and 30 September 2018. The mean prevalence of PAH was 11.6 per million, and the estimated incidence rate was 2.4 per million/year, but it was geographically heterogeneous. Among 80 enrolled children (females, n = 40; 50%), 54 (67.5%) had PAH associated with congenital heart disease (CHD-PAH), 25 (31.25%) had idiopathic PAH (IPAH), and 1 (1.25%) had portopulmonary PAH. At the time of enrolment, 31% of the patients had significant impairment of physical capacity (WHO-FC III). The most frequent comorbidities included shortage of growth ( n = 20; 25%), mental retardation ( n = 32; 40%), hypothyroidism ( n = 19; 23.8%) and Down syndrome ( n = 24; 30%). The majority of children were treated with PAH-specific medications, but only half of them with double combination therapy, which improved after changing the reimbursement policy. The underrepresentation of PAH classes other than IPAH and CHD-PAH, and the geographically heterogeneous distribution of PAH prevalence, indicate the need for building awareness of PAH among pediatricians, while a frequent coexistence of PAH with other comorbidities calls for a multidisciplinary approach to the management of PAH children.

Introduction: Cystic fibrosis (CF) involves chronic inflammation and decreased pulmonary function, which increase caloric demand. Yet, sufficient energy provision is hindered by reduced appetite and fat malabsorption. Brain-derived neurotrophic factor (BDNF), leptin, and neuropeptide Y (NPY) belong to energy balance-regulating factors. We aimed to assess their concentrations in CF patients in order to search for potential clinical correlates., Material and Methods: This was an exploratory, cross-sectional study. Patients' weight and height Z- scores, forced expiratory volume in 1 s (FEV 1 %), exocrine pancreatic status (fecal elastase-1), genotypes, and other characteristics were assessed. Serum concentrations of BDNF, leptin, NPY, IL-6, and TNF-α were measured using ELISA., Results: The study enrolled 56 patients, of whom 29 (52%) were female and 17 (30%) were younger than 16 years. Median (1 st -3 rd quartile) mass Z -score was -0.85 (-1.56-(-0.36)); median FEV 1 was 70.5% (45.0-89.5); 48 (86%) patients had exocrine pancreatic insufficiency and 8 (14%) diabetes. Overall, median concentrations were: BDNF: 33.91 ng/ml (26.40-40.43), leptin: 12.05 ng/ml (8.93-17.77), NPY: 2.86 ng/ml (1.75-4.42). None of these factors correlated with mass Z -score, FEV 1 %, IL-6 or TNF-α. Leptin and NPY correlated negatively (ρ = -0.62, p = 3 × 10 -7 ); BDNF/NPY ratio was associated with leptin (ρ = 0.54, p = 2 × 10 -5 ), BDNF/leptin ratio correlated with NPY (ρ = 0.60, p = 1 × 10 -6 ). In a multivariable regression analysis NPY was weakly, but independently, associated with FEV 1 %, and leptin with age., Conclusions: BDNF and leptin were not associated with weight Z -score or FEV 1 %. Serum NPY concentrations seemed to be lower in CF patients with reduced pulmonary function independently of malnutrition and inflammation., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2018 Termedia & Banach.)

Many methods computing heart rate variability (HRV) have been applied in studies in children. Not all of these methods have a comprehensive physiological interpretation, and not all of studies are in agreement with the Task Force Standards on HRV from 1996, and the New Joint Position Statement on the advances of HRV from 2015. The study aim was to analyse HRV in the 24-h ECGs of healthy children by the Poincare plots and Lomb-Scargle periodograms, and to follow proper HRV recommendations. Additionally, we investigated the associations between age, children's sex and measured HRV indices. One hundred healthy children, aged 3-18 underwent 24-h ECG Holter monitoring. HRV was analyzed by the Poincaré plots and spectral by Lomb-Scargle periodograms of RR intervals. The Mann-Whitney test was used to compare sex differences in HRV, the van Elteren's test was used to correct for the age-gender interaction, and non-parametric Spearman correlation was applied to analyse the association between age and HRV indices. None of the HRV measures differed significantly between boys and girls. None of the HRV indices was modified by the age-gender interaction. There were statistically significant associations of age with measures of ultra-low (rho = 0.42; p < 0.0001), very low (rho = 0.35; p = 00004) and low (rho = 0.30; p = 0.0028) frequency powers, the ratio of the low to high frequency power (rho = 0.38; p = 0.0001), indices of long-term (SD2; rho = 0.37; p = 0.0002) and total (SDNN; rho = 0.33; p = 0.0008) HRV, and the contribution of the long-term HRV to total HRV (CL; rho = 0.32; p = 0.0012). In general, HRV parameters derived from the analyses of Poincaré plots and Lomb-Scargle periodograms appear not to be affected by gender, however, most of them increase with age in the 24-h ECG recordings in healthy children.

Purpose: A lower parasympathetic activity was described in patients with the gastroesophageal reflux disease. We aimed to determine whether gastroesophageal reflux (GER) episodes are associated with a short-term parasympathetic tone variability in children., Methods: In order to address this question we performed simultaneous 24-h esophageal multichannel intraluminal impedance-pH and electrocardiographic monitoring in 16 children (age range 6-18 years), including 8 with asthma and 2 with gastroesophageal reflux disease. After describing duration, height, and acidity of 483 GER episodes we also measured parasympathetic-related heart rate variability parameters in 4 time periods: preceding, containing, following GER, and in-between GERs (control). High frequency (HF) power and root-mean square differences of successive R-R intervals (r-MSSD) were assessed in 2.5-min and 1-min periods, respectively., Results: We did not identify the searched short-term parasympathetic tone changes., Conclusions: In conclusion, GER episodes and their characteristics were not associated with short-term variability of parasympathetic activity in children., (Copyright © 2017 Medical University of Bialystok. Published by Elsevier B.V. All rights reserved.)

The aim of the study was assessment of the usefulness of multiplex real-time PCR tests in the diagnostic and therapeutic process in children hospitalized due to pneumonia and burdened with comorbidities. Methods . The study group included 97 children hospitalized due to pneumonia at the Karol Jonscher Teaching Hospital in Poznań, in whom multiplex real-time PCR tests (FTD respiratory pathogens 33; fast-track diagnostics) were used. Results . Positive test results of the test were achieved in 74 patients (76.3%). The average age in the group was 56 months. Viruses were detected in 61 samples (82% of all positive results); bacterial factors were found in 29 samples (39% of all positive results). The presence of comorbidities was established in 90 children (92.78%). On the basis of the obtained results, 5 groups of patients were established: viral etiology of infection, 34 patients; bacterial etiology, 7 patients; mixed etiology, 23 patients; pneumocystis, 9 patients; and no etiology diagnosed, 24 patients. Conclusions . Our analysis demonstrated that the participation of viruses in causing severe lung infections is significant in children with comorbidities. Multiplex real-time PCR tests proved to be more useful in establishing the etiology of pneumonia in hospitalized children than the traditional microbiological examinations., Competing Interests: All authors declare that they have no conflict of interests.

Introduction: There are only a few available studies evaluating quality of life (QoL) in pediatric patients with cardiac arrhythmia. The aim of the study was to evaluate medical and psychological parameters of the QoL in children with a diagnosed supraventricular tachyarrhythmia (SVT) and to compare the obtained data with a group of healthy children (HC)., Material and Methods: Inclusion criteria: children aged 7-18 with SVT, treated at Poznan University of Medical Sciences, Department of Pediatric Cardiology. The evaluation tools were the WHOQOL-BREF instrument and a questionnaire related to the patient's feelings and observations concerning arrhythmia (Pediatric Arrhythmia Related Score - PARS), developed by the authors and adjusted to the group of arrhythmia patients., Results: The study included 180 SVT children and 83 HC. On the basis of WHOQOL-BREF the SVT group was found to have lower assessment values of QoL within the physical domain (Phd) (mean ± SD: 65.7 ±15.8 vs. 81.6 ±12.8; p < 0.0001) and psychological domain (Psd) (mean ± SD: 75.8 ±15.2 vs. 81.3 ±14.1; p < 0.005). No significant differences were found within the social relationships domain or the environment domain. On the basis of PARS in the SVT group the patients reported significantly increased symptoms within Phd (mean ± SD: 2.3 ±0.7 vs. 1.6 ± 0.3; p < 0.0001) as well as increased negative feelings within Psd (mean ± SD: 2.3 ±0.7 vs. 2.1 ± 0.6; p < 0.005)., Conclusions: Medical and psychological parameters of the QoL in SVT children are significantly lower in comparison with HC. A diagnosis of SVT has no influence on the social and environmental areas of QoL. The PARS appears to be a useful tool to supplement the generic questionnaire for QoL evaluation in SVT children.

We report on a patient with a significantly enlarged right heart caused by a rare right ventricle to right atrium fistula. Cardiac magnetic resonance revealed diagnosis and delineated detailed anatomy of the defect. The shunt was successfully closed with an implantation of Amplatzer Vascular Plug II. We discuss possible causes of this anomaly and its treatment., (Copyright © 2013 Wiley Periodicals, Inc.)

Objectives: The purpose of this paper is to report our 10 years of experience of interventional treatment of patients with hypoplastic left heart syndrome and to focus on the frequency, type, and results of percutaneous interventions during all the stages of palliation, considering the different techniques, devices, and complications., Background: Constant progress in surgical treatment of congenital heart defects in the last decade has significantly improved the prognosis for children with hypoplastic left heart syndrome. However, morbidity and mortality remain relatively high. Modern interventional procedures complement or occasionally replace surgical treatment., Methods: Between January, 2001 and December, 2010, 161 percutaneous interventions were performed in 88 patients with hypoplastic left heart syndrome. Patients were divided into four groups: (a) before the first surgical treatment including hybrid approach, (b) after first-stage Norwood operation, (c) after second-stage bidirectional Glenn operation, and (d) after third-stage Fontan operation., Results: Percutaneous interventions resulted in statistically significant changes in pulmonary artery pressures, vessel diameters, and O2 saturation. Complications occurred in 4.3% of interventions and were related mainly to stent implantation in stenosed pulmonary arteries., Conclusions: Percutaneous interventions may result in haemodynamic stability and reduction in the number of operations. They may result in significant changes in pulmonary artery pressures, vessel diameters, O2 saturation, with a low rate of complications, which are mainly related to stent implantation in the pulmonary arteries.

Introduction: The aim of our prospective study was to evaluate heart rate variability (HRV) in children with aortic valve stenosis (AS) and its relationship with left ventricular mass and peak transaortic valve pressure gradient (PG)., Material and Methods: Sixty children with AS divided into 3 groups according to their PG and 60 healthy controls were studied. Holter ECG monitoring with time domain HRV analysis was performed. Left ventricular mass was calculated by echocardiography., Results: Mean values of all HRV parameters were statistically significantly lower (p < 0.001) in children with AS than in controls (respectively: SDNN 127.8 ±28.2 ms; 162.6 ±38.0 ms, SDNN day 99.7 ±26.6 ms; 134.1 ±36.1 ms, SDNN night 99.9 ±32.8 ms; 123.4 ±45.7 ms, SDANN 112.2 ±27.7 ms; 142.4 ±34.6, SDNNi 62.2 ±16.2 ms; 75.9 ±21.6, RMSSD 39.6 ±12.1 ms; 50.3 ±16.7 ms, rMSSD day 33.6 ±10.9 ms; 43.1 ±14.7 ms, rMSSD night 49.8 ±18.1 ms; 64.4 ±24.9 ms, pNN50 16.4 ±9.5%; 23.5 ±11.7%, pNN50 day 12.0 ±8.5%; 18.4 ±10.7%, pNN50 night; 26.5 ±14.8%; 36.4 ±17.4%. No significant differences between the mean values of HRV parameters in children with different PG and with and without myocardial hypertrophy were found. In children with AS and ventricular arrhythmia SDNN day was significantly lower (p < 0.05) compared to patients without arrhythmia (94.9 ±22.1 ms vs. 109.3 ±22.5 ms)., Conclusions: In children with AS the balance of the autonomic nervous systemic disturbed which manifests in an increase in sympathetic and decrease in parasympathetic activity. Transaortic valve pressure gradient and myocardial hypertrophy do not influence the HRV. The SDNN reduction during the day period may indicate the risk of ventricular arrhythmia in children with AS.