Total Heart Rate Variability Research Articles

Habitual aerobic exercise in healthy postmenopausal women does not augment basal cardiac autonomic activity yet modulates autonomic-metabolic interactions.

The aim of the present study was to examine the effects of habitual exercise training and metabolic health on basal cardiac autonomic function and cardiac autonomic recovery after exercise in healthy postmenopausal women (PMW). Habitually aerobically trained PMW (PMW-tr; 56 ± 1y; n = 11), and untrained PMW (PMW-un; 57 ± 1y; n = 13) and premenopausal women (PreM; ages 26 ± 1y; n = 14) were studied. Cardiac autonomic function, assessed using heart rate variability (HRV), was measured before and one hour after 45-minutes of moderate-intensity exercise (60% VO2peak). Fast Fourier frequency domain measures of high (HF; 0.15 Hz-0.4 Hz), low (LF; 0.04 Hz-0.15 Hz), very low (VLF; 0.01 Hz-0.04 Hz), and Total (VLF + LF + HF) HRV were assessed. Serum estradiol, insulin, and glucose were determined, and HOMA-IR, an index of insulin resistance, was calculated. In PMW groups, body composition and serum markers did not differ (P > 0.05). Pre-exercise, heart rate was lower (P < 0.05) in PMW-tr than PMW-un, yet HRV did not differ (P > 0.05). In PMW-tr only, HF was inversely associated (P < 0.05) with insulin (r = -0.738) and HOMA-IR (r = -0.758). In PreM, HRV was higher than PMW (P < 0.05) and was positively correlated with estradiol (P < 0.05). Postexercise, HRV was decreased within all groups (P < 0.05) yet remained higher in PreM (P < 0.05), and similar (P > 0.05) between PMW. Basal and postexercise HRV does not differ between habitually aerobically trained and untrained PMW. However, greater insulin sensitivity was associated with higher cardiac parasympathetic tone in trained PMW only. Exercise training may favorably modulate cardiac autonomic-metabolic interactions in PMW.

The Effects of Heart Rate Variability (HRV) Biofeedback on HRV Reactivity and Recovery During and After Anger Recall Task for Patients with Coronary Artery Disease.

Patients with coronary artery disease (CAD) often experience anger events before cardiovascular events. Anger is a psychological risk factor and causes underlying psychophysiological mechanisms to lose balance of the autonomic nervous system (ANS). The heart rate variability (HRV) was the common index for ANS regulation. It has been confirmed that heart rate variability biofeedback (HRV-BF) restored ANS balance in patients with CAD during the resting state. However, the effects of HRV-BF during and after the anger event remain unknown. This study aimed to examine the effects of HRV-BF on ANS reactivity and recovery during the anger recall task in patients with CAD. This study was a randomized control trial with a wait-list control group design, with forty patients in the HRV-BF group (for six sessions) and 44 patients in the control group. All patients received five stages of an anger recall task, including baseline, neutral recall task, neutral recovery, anger recall task, and anger recovery. HRV reactivity in the HRV-BF group at the post-test was lower than that in the control group. HRV recovery at the post-test in the HRV-BF group was higher than that in the control group. The HRV-BF reduced ANS reactivity during anger events and increased ANS recovery after anger events for CAD patients. The possible mechanisms of HRV-BF may increase total HRV, ANS regulation, and baroreflex activation at anger events for patients with CAD, and may be a suitable program for cardiac rehabilitation.

Особенности регуляции ритма сердца у подростков разных этнических групп в условиях Северо-Востока России

The climatic and geographical conditions of Russia’s northeastern region form certain biological adaptation mechanisms in the population, contributing to the body’s optimal functioning in this environment. In spite of the fact that the body’s adaptation mechanisms to extreme conditions of Northeast Russia have been sufficiently studied, this issue remains relevant. The influence of negative factors during adolescence, when the body is extremely vulnerable, can disrupt the adaptation mechanisms and initiate pre-pathological and pathological processes. The function of the cardiovascular system is one of the main indicators that can be used to evaluate the body’s adaptive mechanisms. Therefore, the purpose of this research was to study heart rhythm regulation mechanisms in adolescents (Russians and Yakuts) permanently living in Northeast Russia. Materials and methods. Heart rate variability (HRV) parameters were evaluated in adolescents (native Yakuts and second-generation Russian newcomers to Yakutsk) aged 14–15 years (mean age 14.34 ± 0.17 years) studying at the secondary schools of Yakutsk. Results. We found an increase in the share of the very low frequency spectrum in the total HRV spectrum in Russian girls and boys (48.8 and 47.5 %, respectively) and in Yakut boys (47.9 %), which indicates an increased activity of neurohumoral regulation of metabolic processes in adolescents due to the extreme climatic and geographical conditions. Moreover, some ethnic features of heart rate regulation were identified. Unlike their Russian peers, Yakut adolescents showed statistically significant sex-related differences in HRV (p &lt; 0.01): in boys the autonomic balance is shifted towards the sympathetic division, the power of the highfrequency spectrum is decreased, and the stress index is increased. HRV spectral power parameters in the remaining groups correspond to the average age norm and indicate a favourable course of adaptation processes with a high level of the body’s mobilization and restorative potential.

The association between chronotype and sleep quality among female home care workers performing shift work

ABSTRACT There is a scarcity of evidence on the association between shift work, sleeping parameters, heart rate variability (HRV), and chronotype, i.e., morningness and eveningness. The aims of this study were to 1) compare participants with different chronotypes (morning (M), evening (E), or neither (N)) in terms of their total sleep time, sleep efficiency, and HRV parameters, taking their age into account, and 2) examine whether self-reported work-related stress, the length of the working career and years performing shift work affect this association. The participants of the study were home care workers working in two shifts in one municipality in Eastern Finland (N = 395). Of these, 52 females (mean age 42.78 y, SD 12.92 y) completed the study questionnaire and participated in physiological measurements. Several sleep-related parameters were assessed (total sleep time, sleep efficiency, number of awakenings, and length of awakening) and indices of autonomic nervous system based on HRV were calculated. The participants worked in two shifts: a morning shift (7:00–15:00 h) and an evening shift (14:00–21:30 h). All these parameters were assessed during the night before the first work shift (N1), the night before the second work shift (N2), the night before the final work shift (N3), and the night before the first day off work (N4). According to the results, 21.2% of the participants were M-types, 17.3% were E-types, and 61.5% were N-types. On average, the participants had been in working life for 18.8 years and performing shift work for 13.7 years. On night N3, E-types had a significantly shorter total sleep time and spent less time in bed compared to M- and N-types. The total sleep time of M-type and N-type participants was on average 66 minutes and 82 minutes longer, respectively, when compared to E-types on night N3. There were no statistically significant differences in actigraphy-based sleep quality parameters between M-, N-, and E-types on nights N1, N2, and N4. Our results together indicate that M- and N-type individuals may have better sleep quality than E-types, which was also reflected in HRV parameters. Further research with longitudinal study design and workplace interventions is needed to determine how the chronotype can be optimally and individually utilized to improve the health and well-being of morning-type and evening-type people. This is particularly important for both younger and older workers entering the workforce to support healthier and longer working lives.

Toward Evidence-Based Severity Assessment in Mouse Models with Repeated Seizures: (II.) Impact of Surgery and Intrahippocampal Kainate

Introduction: Chronic epilepsy models require neurosurgical procedures including depth electrode implants. The intrahippocampal kainate model is a frequently used chronic paradigm, which is based on chemoconvulsant administration and status epilepticus induction during the surgical procedure. This experimental approach raises the question of the extent to which this approach affects postsurgical recovery. In addition to the short- and long-term impact of the surgical intervention, a potential impact of highly frequent electrographic seizure events needs to be considered in the context of severity assessment. Methods: Various behavioral, biochemical, and telemetric parameters were analyzed in four experimental groups of mice: 1st naive, 2nd with transmitter implants, 3rd with transmitter and electrode implants, and 4th with transmitter implants, electrode implants, and kainate-induced status epilepticus. Results: During the early postsurgical phase, transmitter implants caused a transient impact on Mouse Grimace scores and intragroup increase of fecal corticosterone metabolites. Additional craniotomy was associated with an influence on total heart rate variability and fecal corticosterone metabolites. Heart rate and Irwin score increases as well as a prolonged increase in Mouse Grimace scores pointed to an added burden related to the induction of a nonconvulsive status epilepticus. Data from the chronic phase argued against a relevant influence of frequent electrographic seizures on behavioral patterns, fecal corticosterone metabolites, heart rate, and its variability. However, Irwin scores indicated long-term changes in some animals with increased reactivity, body tone, and Straub tail. Interestingly, selected behavioral and telemetric data from the early post-status epilepticus phase correlated with the frequency of electrographic seizure events in the chronic phase. Conclusion: In conclusion, our findings argue against the pronounced impact of highly frequent electrographic seizures on the well-being of mice. However, an increased level of nervousness in a subgroup of animals should be considered for handling procedures and refinement measures. In the early postsurgical phase, several parameters indicate an influence of the interventions with evidence that the nonconvulsive status epilepticus can negatively affect the recovery. Thus, the development and validation of refinement efforts should focus on this experimental phase. Finally, the datasets suggest that simple readout parameters may predict the long-term consequences of the epileptogenic insult. Respective biomarker candidates require further validation in the follow-up studies in models with subgroups of animals with or without epilepsy development.

Вариабельность сердечного ритма при шизофрении и шизоаффективном расстройстве

Objective of the Review: To analyze and systematize the results of the studies of heart rate variability in schizophrenia and schizoaffective disorder. Key points. Most studies demonstrate a reduction in total heart rate variability and a decrease in parasympathetic tone and reactivity in patients with schizophrenia and schizoaffective disorder, including in response to a cognitive or stress load. And also the baroreflex sensitivity decrease was revealed. Autonomic cardiac dysregulation detected in unmedicated patients with schizophrenia, as well as in healthy first-line relatives. The extent of these changes correlates with the severity of productive, negative and affective symptoms, as well as with the presence of metabolic syndrome. Autonomic cardiac dysregulation is much more pronounced in psychotic states. Antipsychotics with anticholinergic and/or α1-adrenolytic activity can exacerbate these changes. Reductions in total heart rate variability and vagal activity are detected not only in schizophrenia, but also in other mental and somatic disorders, in the pathogenesis of which distress is involved. Conclusion. The possibility of using heart rate variability indicators as additional criteria for assessing the severity of psychosis, predicting the effectiveness of therapy, as well as for early stratification of cardiovascular risks requires further study in scientific research. Keywords: heart rate variability, autonomic nervous system, schizophrenia, schizoaffective disorder, antipsychotics, biomarkers.

ВЗАИМОСВЯЗИ ПОКАЗАТЕЛЕЙ БИОЭЛЕКТРИЧЕСКОЙ АКТИВНОСТИ ГОЛОВНОГО МОЗГА, ВЕГЕТАТИВНОЙ РЕГУЛЯЦИИ РИТМА СЕРДЦА И ГЕМОДИНАМИКИ У БОЛЬНЫХ АРТЕРИАЛЬНОЙ ГИПЕРТОНИЕЙ ЖИТЕЛЕЙ СРЕДНЕГОРЬЯ

Interrelation between amplitude and frequency of the α- and β- brain waves, heart rate variability (HRV) and hemodynamics was studied in 65 hypertensive patients (level 2) and compared to 75 healthy people. Methods of the investigations included EEG, 24-hour Holter monitoring, echo-cardiography, blood pressure measurement and HRV calculation. In patients, α and β parameters decreased by 27 to 35 %, respectively. In comparison to normal people, reductions of α and β amplitudes as well as powers made up 20%, 30 % and 16–45 %, respectively. Total HRV in patients decreased 60 %. Interrelations between the α- and β- waves, HRV and hemodynamics were numerous and multidirectional in patients, whereas in normal people they were weak or absent at all. The results evidence interrelations between the cerebral bioelectrical activity, sympathetic heart rate regulation and hemodynamics in hypertensive patients living in a midaltitude region.

Features of endothelial function and autonomic regulation of heart rhytm in patients with vasospastic angina

BACKGROUND: The clinical features of vasospastic angina are well known, but pathogenesis remains a subject of discussion. Changes in the autonomic regulation of coronary artery tone and endothelial function that contribute to the development of vasospasm are not well understood. The data on the subject from the published studies are contradictory.&#x0D; AIM: To evaluate features of endothelial function and autonomic regulation of heart rhythm in patients with vasospastic angina.&#x0D; MATERIALS AND METHODS: The study included 16 patients with proven vasospastic angina. All the patients have been evaluated for the heart rate variability at rest and vegetative tests (deep breathing, and active standing tests). Endothelial function has been assessed in terms of reactive hyperemia index by peripheral arterial tonometry using an Endo-PAT 2000 device.&#x0D; RESULTS: The baseline of the total heart rate variability was borderline with the normal parameters SDNN 50 (32.5; 50) ms in the patients with vasospastic angina. There were 14 patients who have demonstrated an imbalance of the autonomic nervous system at rest, mainly due to an increase of parasympathetic influences. The appropriate reaction of the autonomic nervous system, characterized by an increase of vagal influences, has been determined in 13 patients in the deep-breathing test. A paradoxical reaction, characterized by an increase of vagal influences on the heart rhythm, has been registered in 13 patients in the active standing tests. Endothelial dysfunction has been observed in half of the studied patients. Furthermore, a combination of both pathophysiological mechanisms, i.e., endothelial and autonomic dysfunctions have been observed in all the patients with a reduced reactive hyperemia index.&#x0D; CONCLUSIONS: According to the results of our study, the parasympathetic influences of the autonomic nervous system on the heart rhythm were predominant in the patients with vasospastic angina, which is not typical for coronary heart disease. All the patients had autonomic or endothelial dysfunction. A combination of both pathophysiological mechanisms has been observed in half of the examined patients.

Heart rhythm and autonomic regulation disorders in chronic coronary syndrome patients with community-aсquired pneumonia

Pneumonia presents a considerable challenge in patients with cardiovascular disease due to an increase in the incidence, difficulties of diagnosis and treatment, high mortality. Aim: to study the characteristics of cardiac arrhythmias and heart rhythm autonomic regulation in patients with chronic coronary syndrome (CCS) and community-acquired pneumonia (CAP), and to define their relationship with the clinical features of the disease. Materials and methods. A monocenter cross-sectional study analyzed 90 patients with CCS in parallel groups. The main group included 60 CCS patients with CAP; the control group consisted of 30 patients without concomitant CAP. A complex clinical examination of patients was performed on 1–3 days of hospital stay in accordance with the National Recommendations. Holter ECG monitoring was performed using a CARDIOSENS K device (XAI-MEDICA, Ukraine). Results. Based on the results of 24-hour ECG monitoring, heart rhythm disorders, increased duration of myocardial ischemia and ST-segment depression depth with an increase in the total duration of tachycardia episodes within 24 hours were more common in the main group patients. The severity of CAP on the PSI/PORT scale was correlated with the 24-hour mean heart rate (r = +0.31, P &lt; 0.05), the number of ventricular extrasystoles – with respiratory rate (r = +0.29, P &lt; 0.05), supraventricular extrasystoles – with the duration of ST-segment depression (r = +0.57, P &lt; 0.05). In patients with CCS and CAP, there was a decrease in the total heart rate variability (HRV), mainly in the passive period, combined with an increase in the LF/HF ratio and stress index (SI), which was directly correlated with the severity of CAP and intoxication syndrome. Conclusions. Patients with CCS and CAP are characterized by the increased 24-hour heart rate, duration of ST-segment depression, frequency of supraventricular and ventricular arrhythmias on 24-hour Holter monitoring, paroxysms of atrial fibrillation with the decreased total HRV combined with significantly increased activity of the sympathetic autonomic nervous system.

Порівняльна характеристика сенсомоторних реакцій висококваліфікованих спортсменів з різними типами регуляції серцевого ритму

The purpose of the study was a comparative analysis of sensorimotor reactions in highly trained athletes with different types of heart rate regulation. Materials and methods. 202 highly trained male athletes aged 22.6±2.8 years, who are engaged in acyclic sports – martial arts (karate, taekwondo, kickboxing, boxing, freestyle wrestling, Greco-Roman wrestling, judo, sambo) and games (water polo, soccer) were examined. The experience in sports was 10.3±3.1 years. All studies were conducted in the pre-competition period in the morning. Based on the study of heart rate variability in athletes, the type of heart rate regulation was determined. The basis for determining the types of regulation is the classification of heart rate variability indicators, taking into account their inclusion in certain limits. Heart rate variability indicators that reflect the dual-circuit model of heart rate regulation and are used for diagnosis include: total heart rate variability – total power (ms2), very low frequency (ms2), and stress-index (e.u.), which reflect the various chains of regulatory effects on heart rate. According to certain data types, 4 groups were formed. 1 group (type I) consisted of 42 athletes, 2 (type II) – 28 athletes, 3 (type III) – 88 athletes, 4 (type IV) – 44 athletes. The study of sensorimotor function was performed using the device KMM-3. Results and discussion. It is shown that the most balanced sensorimotor reactions are in athletes with type III regulation of heart rate. The most strain sensorimotor reactions are observed in type II regulation of heart rate, which is reflected in the pronounced central asymmetry of movement control with acceleration to the left against the background of deteriorating accuracy of right (due to flexors) and left (due to extensors) limbs, and the right-hand predominance. Sensorimotor reactions are quite strain in type IV of heart rate regulation, which is characterized by slow reactions at the synaptic and peripheral levels. In type I of heart rate regulation, the disorders observed at the central level of regulation relate to the asymmetry of short-term motor memory processes, which are significantly reduced in the left hemisphere. Conclusion. The study shows that the differences in the regulatory support of heart rate in highly qualified athletes are accompanied by characteristic differences in sensorimotor function. The latter can be useful for the diagnosis and further correction of conditions associated with the development of overexertion and overtraining

P151 Short-term mandibular advancement splint therapy for Obstructive Sleep Apnoea improves parasympathetic modulation

Abstract Introduction Altered autonomic function (specifically, sympathoexcitation and vagal withdrawal) contributes to cardiovascular risk. Obstructive sleep apnoea (OSA) is associated with altered autonomic function. Heart rate variability (HRV) is a non-invasive measure of autonomic function. We aimed to assess whether short-term OSA treatment with mandibular advancement splints (MAS) improves autonomic function measured by HRV. Methods A retrospective analysis of participants in MAS treatment studies (N=105, 56% male, age, 56±1 years; BMI, 30±5 kg/m2) was undertaken. Nocturnal HRV was assessed using electrocardiograms from pre and post-treatment polysomnograms. HRV was calculated across 2-minute epochs over the entire electrocardiogram and divided into each sleep stage (wake, non-rapid eye movement (NREM), and rapid eye movement (REM)). HRV measures reflecting sympathetic (normalised low frequency (LFnu)), parasympathetic (pNN50%, RMSSD (ms), normalised high frequency (HFnu)), total HRV (SDNN (ms) and HTI) and R-R interval were calculated. Changes in HRV measures following treatment were assessed (paired t-test) and compared to AHI change (linear regression, with adjustment for age, sex, BMI). Results Following MAS treatment, HTI increased (14.78±39.99, p=0.008), and LFnu reduced during wake (-0.43±38.18, p=0.03). Linear regression, showed AHI reduction related to increased R-R interval during wake (-0.002, 0.001), p=0.009) [unstandardised β/SE] and REM (-0.002, 0.001) [unstandardised β/SE], p=0.008), and increased pNN50% during wake (-0.24, 0.08), p=0.005) [unstandardised β/SE] suggesting MAS efficacy relates to these improvements. Conclusion We found evidence of reduced sympathetic and increased parasympathetic modulation, following short-term MAS therapy. This suggests MAS therapy has potential to improve cardiac autonomic function and hence reduce cardiovascular risk.

Low-Intensity Laser Therapy As a Method to Reduce Stress Responses after Septoplasty.

The aim of the study was to evaluate the effectiveness of the use of photobiomodulation therapy (PBMT) to minimize acute pain in the early postoperative period in patients after septoplasty. In total, 62patients underwent septoplasty under general anesthesia (40 men and 22 women, 18-44 years old) followed by nasal tamponade. Patients of the 1st group did not undergo PBMT, and patients of the 2nd group received PBMT 3, 6, and 24 h after septoplasty (infrared pulsed laser radiation, λ = 0.890 μm, P = 10 W, 2min in the projection of the wings of the nose). After 48 h, after the removal of tampons, intranasal PBMT with a nozzle in the red range, with λ = 0.63 μm, P = 8 mW, 2 min. ULF, HF, LF, and total power of heart rate variability (HRV), pain syndrome was assessed. ULF, LF, HF, total HRV power were significantly lower in group 2, compared to group 1. In the period from 6 to 24 h after septoplasty, patients of group 1 experienced higher pain than patients with PBMT (p < 0.001). The use of PBMT after septoplasty against the background of nasal tamponade helps to reduce the severity of pain syndrome and the inflammatory response to surgical stress and, consequently, leads to less pronounced changes in the autonomic nervous system in response to surgical stress.

Changes in the Time-Domain of Heart Rate Variability and Corticosterone after Surgical Trauma to the Nasal Septum in Rats.

The aim of the work was to study changes in the time range of heart rate variability (HRV) against the background of changes in the concentration of corticosterone in blood plasma in rats after surgical trauma to the nasal septum. Septoplasty was simulated in 30 mature male Wistar rats weighing 210-290 g. ECG was recorded with subsequent analysis of the time domain of HRV, as well as blood sampling to estimate changes in the concentration of corticosterone in the blood plasma was performed. As a result, SDNN significantly increased in comparison with the control on days 2 and 3 (p < 0.001) but decreased on days 4-5 (p < 0.001) and 6 (p < 0.01). rMSSD changed in waves with two irregular peaks on days 1 and 6. SDNN/rMSSD, in comparison with the 1st day of the postoperative period, increased on the 2nd day, continued to increase (p<0.05), and then began to decrease on day 4 (p < 0.01). The total HRV power of was low throughout the postoperative period (p < 0.001), except for day 3, when it was equal to the control data. The increase in the total power index fell on day 3 after the operation (p <0.01), after which its decline was observed again. The concentration of corticosterone in the blood plasma in rats was significantly higher than before (p < 0.001). On postoperative day 2 to 4, its plateau was determined. Simulation of septoplasty leads to changes in the time range of HRV, an increase in the concentration of corticosterone in the blood plasma in rats with its maximum at the time of surgery and 24 h later, and the formation of a "plateau" on postoperative days 2 to 4, which coincides with the changes in HRV.

Heart Rate Variability, Time Estimation and Internet-Dependent Behaviour in 16-17-Year-Old Adolescents: A Study in Russian Arctic.

Internet-dependent behaviour in adolescents can contribute to a change in the function of the nervous system, which is reflected in the violation of time perception and autonomic regulation of the heart rate. The aim of the study was to determine groups of individuals with different risks of Internet addiction (IA) in relation to heart rate variability (HRV) parameters and the efficiency of time estimation in adolescents aged 16–17 years living in the Russian Arctic. Adolescents aged 16–17 years (n = 49–32 females, 17 males) living in Yamalo-Nenets Autonomous Okrug (Russia) were observed. Chen Scale Internet Addiction (CIAS) was used. The duration of an individual 1 min was determined. HRV parameters were determined using the "Varicard" equipment (Russia). In 16–17-year-old adolescents with different levels of risk of developing IA, including signs of IA, we revealed a high severity of symptoms of withdrawal from Internet use, difficulty in time estimation against the background of sympathicotonia and a decrease in vagal regulation of heart rate. In individuals with minimal symptoms of withdrawal from Internet use, the total HRV and vagal activity remain higher than in those with severe withdrawal symptoms, and their time estimation remains effective.

Effects of bilateral lung transplantation on cardiac autonomic modulation and cardiorespiratory coupling: a prospective study

BackgroundAlthough cardiac autonomic modulation has been studied in several respiratory diseases, the evidence is limited on lung transplantation, particularly on its acute and chronic effects. Thus, we aimed to evaluate cardiac autonomic modulation before and after bilateral lung transplantation (BLT) through a prospective study on patients enrolled while awaiting transplant.MethodsTwenty-two patients on the waiting list for lung transplantation (11 women, age 33 [24–51] years) were enrolled in a prospective study at Ospedale Maggiore Policlinico Hospital in Milan, Italy. To evaluate cardiac autonomic modulation, ten minutes ECG and respiration were recorded at different time points before (T0) and 15 days (T1) and 6 months (T2) after bilateral lung transplantation. As to the analysis of cardiac autonomic modulation, heart rate variability (HRV) was assessed using spectral and symbolic analysis. Entropy-derived measures were used to evaluate complexity of cardiac autonomic modulation. Comparisons of autonomic indices at different time points were performed.ResultsBLT reduced HRV total power, HRV complexity and vagal modulation, while it increased sympathetic modulation in the acute phase (T1) compared to baseline (T0). The HRV alterations remained stable after 6 months (T2).ConclusionBLT reduced global variability and complexity of cardiac autonomic modulation in acute phases, and these alterations remain stable after 6 months from surgery. After BLT, a sympathetic predominance and a vagal withdrawal could be a characteristic autonomic pattern in this population.

Changes in Heart Rate and Heart Rate Variability During Surgical Stages to Completed Fontan Circulation

Arrhythmia is related to heart rate variability (HRV), which reflects the autonomic nervous regulation of the heart. We hypothesized that autonomic nervous ganglia, located at the junction of the superior vena cava’s entrance to the heart, may be affected during the bidirectional Glenn procedure (BDG), resulting in reduced HRV. We aimed to investigate changes in heart rate and HRV in a cohort of children with univentricular heart defects, undergoing stepwise surgery towards total cavopulmonary connection (TCPC), and compare these results with healthy controls. Twenty four hours Holter-ECG recordings were obtained before BDG (n = 47), after BDG (n = 47), and after total cavopulmonary connection (TCPC) (n = 45) in patients and in 38 healthy controls. HRV was analyzed by spectral and Poincaré methods. Age-related z scores were calculated and compared using linear mixed effects modeling. Total HRV was significantly lower in patients before BDG when compared to healthy controls. The mean heart rate was significantly reduced in patients after BDG compared to before BDG. Compared to healthy controls, patients operated with BDG had significantly reduced heart rate and reduced total HRV. Patients with TCPC showed reduced heart rate and HRV compared with healthy controls. In patients after TCPC, total HRV was decreased compared to before TCPC. Heart rate was reduced after BDG procedure, and further reductions of HRV were seen post-TCPC. Our results indicate that autonomic regulation of cardiac rhythm is affected both after BDG and again after TCPC. This may be reflected as, and contribute to, postoperative arrhythmic events.

Electrophysiological Brain-Cardiac Coupling in Train Drivers during Monotonous Driving.

Electrophysiological research has previously investigated monotony and the cardiac health of drivers independently; however, few studies have explored the association between the two. As such the present study aimed to examine the impact of monotonous train driving (indicated by electroencephalogram (EEG) activity) on an individual’s cardiac health as measured by heart rate variability (HRV). Sixty-three train drivers participated in the present study, and were required to complete a monotonous train driver simulator task. During this task, a 32 lead EEG and a three-lead electrocardiogram were recorded from each participant. In the present analysis, the low (LF) and high frequency (HF) HRV parameters were associated with delta (p < 0.05), beta (p = 0.03) and gamma (p < 0.001) frequency EEG variables. Further, total HRV was associated with gamma activity, while sympathovagal balance (i.e., LF:HF ratio) was best associated fronto-temporal delta activity (p = 0.02). HRV and EEG parameters appear to be coupled, with the parameters of the delta and gamma EEG frequency bands potentially being the most important to this coupling. These relationships provide insight into the impact of a monotonous task on the cardiac health of train drivers, and may also be indicative of strategies employed to combat fatigue or engage with the driving task.

Gorban Features of autonomic regulation of heart rate depending on the composition of the body in young people

Objective: of the research was to study preclinical changes in heart rate variability (HRV) associated with overweight and obesity in young people in order to determine the targets of predictive therapy.Material and methods: the study involved 105 young men and 111 young women aged 18 to 30 years. Questionnaires, anthropometry with determination of body mass index and waist circumference, bioimpedansometry with determination of body fat (BF) and visceral fat (VF) level, as well as monitoring of HRV based on short (ten-minute) records were carried out.Result: young people of both sexes showed a high frequency of overweight (24.1%) and obesity (18.5%), as well as a low level of physical activity (FA, 46.3%). In 28.8% of young men and 12.5% of young women with overweight and obesity, there was a high level of VF. Taking into account the outstripping increase in VF as compared to BF, it is reasonable to divide the VF levels into low (&lt;5 conventional units), intermediate (5-9 conventional units), and high (&gt; 9 conventional units). In overweight young people, compared with normal body weight, HRV is characterized by less pronounced parasympathetic activity, and in girls compared with young men, there is less total HRV. A high HRV level is associated with such HRV indicators as an increase values of LF/ HF and SDANN, reflecting, respectively, a reduction in the parasympathetic and enhanced sympathetic activity of the autonomic nervous system with a predominance of the central circuit of heart rhythm regulation over the autonomous one.Conclusion: to diagnose autonomic imbalance in young people, it is necessary to determine the composition of the body, FA level, take into account the individual dynamics of HRV parameters, since they rarely exceed the norm. Changes in total HRV, sympathetic and parasympathetic activity during the non-drug correction of obesity should be monitored with an emphasis on pNN (50) and SDANN indicators associated with BF, and when correcting physical activity — on the indicator of voltage index of regulatory systems.

Paradoxical effect of cumulative stress exposure on information processing speed in Hispanics/Latinos with elevated heart rate variability

Chronic stress has a deleterious effect on prefrontal lobe functioning. Empirical evidence suggests elevated vagal tone, indexed by elevated heart rate variability (HRV), mitigates the effect of mental stress on frontal lobe function. Here, the mitigating effect of HRV on stress-related decrements in cognitive performance is assessed based on information processing speed (DSST), word fluency and verbal learning task performance. Artifact free electrocardiogram (ECG) data was analyzed from 1420 Hispanic/Latino adults from the Sociocultural Ancillary of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). A 12-lead ECG was used to collect short-term recordings of the root mean square of successive differences in all normal R-peak to R-peak intervals (RMSSD) and the change between adjacent beats and the standard deviation of those intervals (SDNN) as indices of total HRV. As predicted, an interaction emerged for HRV and stress on the task presumed to require the greatest prefrontal lobe involvement, i.e., the DSST. After accounting for sociodemographic factors, chronic stress was associated with better DSST performance amongst individuals at higher quartile of SDNN, but not RMSSD. The paradoxical effect for greater stress exposure on DSST performance may in part be explained by increased speed of information processing and decision making often reported in high-stress cohorts. The nature of this interaction highlights the importance of examining the relationship between stress and cognition across a spectrum of vagal tone.

Эффективность кардиобиоуправления у подростков 15–16 лет после физической нагрузки в условиях низких температур

Short-term biofeedback (BF) training provides effective restoration of the cardiovascular system (CVS) after physical exercise. Purpose: assessment of CVS reactivity in adolescents aged 15–16 years during a heart rate variability (HRV) BF session following a speed-strength exercise (thricerepeated standing long jump) in the open air (from –1 to –10 °C). Materials and methods. Healthy adolescents were examined: an experimental group (n = 15) subject to HRV BF training (3 min) using Varikard equipment (Ramena, Russia) in order to increase the total HRV power and a control group (n = 12). The following stages of recording HRV and blood pressure indicators were singled out: background (initial indicators), period immediately after physical activity, and recovery period with HRV training (experimental group) or being at rest (control group). Results. During the recovery period after a HRV BF session, subjects from the experimental group showed significantly higher total HRV power compared with the control (p = 0.04). In experimental group individuals with a heart rate of less than 90 bpm against the background of its increase during BF training, stress index did not change significantly. In subjects with tachycardia (above 90 bpm), heart rate and stress index remained elevated at all stages. Conclusion. Short-term BF training (3 min) after a speed-strength exercise in a cold environment increases the total HRV power in adolescents; the degree of reduction in sympathetic response depends on the initial heart rate level. The relative increase in heart rate during HRV BF training after physical exercise in a cold environment indicates the need for a longer BF session (over 3 min) in order to achieve a more pronounced influence of vagal effects on the heart rhythm.