Spectral Analysis Of Heart Rate Research Articles

Fetal heart rate spectral analysis in raw signals and PRSA-derived curve: normal and pathological fetuses discrimination.

Cardiotocography (CTG) is the most common technique for electronic fetal monitoring and consists of the simultaneous recording of fetal heart rate (FHR) and uterine contractions. In analogy with the adult case, spectral analysis of the FHR signal can be used to assess the functionality of the autonomic nervous system. To do so, several methods can be employed, each of which has its strengths and limitations. This paper aims at performing a methodological investigation on FHR spectral analysis adopting 4 different spectrum estimators and a novel PRSA-based spectral method. The performances have been evaluated in terms of the ability of the various methods to detect changes in the FHR in two common pregnancy complications: intrauterine growth restriction (IUGR) and gestational diabetes. A balanced dataset containing 2178 recordings distributed between the 32nd and 38th week of gestation was used. The results show that the spectral method derived from the PRSA better differentiates high-risk pregnancies vs. controls compared to the others. Specifically, it more robustly detects an increase in power percentage within the movement frequency band and a decrease in high frequency between pregnancies at high risk in comparison to those at low risk.

Impaired parasympathetic function in long-COVID postural orthostatic tachycardia syndrome – a case-control study

PurposeEighty percent of patients infected by SARS-CoV-2 report persistence of one symptom beyond the 4-week convalescent period. Those with orthostatic tachycardia and orthostatic symptoms mimicking postural tachycardia syndrome, they are defined as Long-COVID POTS [LCP]. This case-control study investigated potential differences in autonomic cardiovascular regulation between LCP patients and healthy controls.MethodsThirteen LCP and 16 healthy controls, all female subjects, were studied without medications. Continuous blood pressure and ECG were recorded during orthostatic stress test, respiratory sinus arrhythmia, and Valsalva maneuver. Time domain and power spectral analysis of heart rate [HR] and systolic blood pressure [SBP] variability were computed characterizing cardiac autonomic control and sympathetic peripheral vasoconstriction.ResultsLCP had higher deltaHR (+ 40 ± 6 vs. + 21 ± 3 bpm, p = 0.004) and deltaSBP (+ 8 ± 4 vs. -1 ± 2 mmHg, p = 0.04) upon standing; 47% had impaired Valsalva maneuver ratio compared with 6.2% in controls (p = 0.01). Spectral analysis revealed that LCP had lower RMSSD (32.1 ± 4.6 vs. 48.9 ± 6.8 ms, p = 0.04) and HFRRI, both in absolute (349 ± 105 vs. 851 ± 253ms2, p = 0.03) and normalized units (32 ± 4 vs. 46 ± 4 n.u., p = 0.02). LFSBP was similar between groups.ConclusionsLCP have reduced cardiovagal modulation, but normal sympathetic cardiac and vasoconstrictive functions. Impaired parasympathetic function may contribute to the pathogenesis of Long-COVID POTS syndrome.

Адаптационные, регуляторные и функциональные возможности студентов с разным биологическим возрастом по шкале «Bio-age»

Biological age (BA) is determined by a set of metabolic, structural, functional, regulatory and adaptive characteristics of the body. Assessment of biological age is the key to studying the influence of time and environmental conditions on changes in the body at all stages of ontogenesis. The purpose of this article was to study the adaptive, regulatory and functional characteristics of students of different biological ages, determined using the Bio-Age scale. Materials and methods. The research involved 521 students aged 18–25 years who were examined at the Health Centre based at Arzamas City Hospital No. 1. These included anthropometry, bioelectrical impedance analysis, cardiointervalography, anklebrachial index test, as well as determination of total cholesterol and glucose levels in the blood. Results. Biological age assessment using the Bio-Age scale showed that only in 1/2 of the students the biological age coincides with the chronological age, while 1/3 of the subjects already have an accelerated rate of ageing. The adaptive capabilities of students whose biological age is less than the chronological age (BA < CA) are better than of those whose biological age exceeds the chronological age (BA > CA). This is confirmed not only by the adaptation degree according to R.M. Baevsky’s method, but also by stress index dynamics and by the parameters of heart rate spectral analysis. In students with BA < CA, the functional state of the body is optimal both at rest and during an orthostatic test: the total power of the cardiointervalogram spectrum decreases due to reduced activity of the parasympathetic division. In students with BA > CA, both in the supine and prone positions, a mismatch in the functioning of different parts of the autonomic nervous system was identified, namely, greater involvement of the central parts of heart rate control, increased sympathetic influences and a weaker activity of the parasympathetic division of the autonomic nervous system.

COMPREHENSIVE ASSESSMENT OF PSYCHOPHYSIOLOGICAL FACTORS IN THE PROFESSIONAL ADAPTATION OF CADET-GRADUATES TO MILITARY SERVICE

The article provides a comprehensive assessment of the psychophysiological factors affecting the professional adaptation of cadets. It emphasizes that professional development entails the formation of professional orientation, competence, socially significant and professionally important qualities, their integration, readiness for continuous professional growth, and the search for optimal methods to perform activities of high quality and creativity in accordance with individual psychological characteristics. Various approaches to specialist development have been examined by researchers and practitioners, including professional self-determination, stages of specialization, development of professionally important qualities, motivation in work activities, and the fundamentals of labor activity. The main theories that unify these approaches are the theory of types of professional life (structural concepts), motivational theories, and theories of individuality. The study highlights that the adaptation process is influenced by personal factors such as stress resistance, personality type, and emotional perception. The research utilized data obtained through a rhythmograph system, which monitors ECG signals and heart rate variability in the first standard lead, allowing for statistical time and spectral analysis of heart rate. In the initial stage, the assessment of nonverbal and general intelligence development levels was analyzed using the "Color Progressive Matrices" test by J. C. Raven. In the subsequent stage, the correlation between intelligence level and LF norm, HF norm, and LnLF/HF under load was determined. Finally, the adaptability level of the respondents to modern functioning conditions was assessed using the multi-level personality questionnaire "Adaptability" by A. Maklakov and S. Chermianin. The obtained data indicate an inverse proportional relationship between these indicators: "high stress - low adaptability" and vice versa. The article also highlights the significance of nervous-psychic tension, in addition to stress, as an unfavorable factor affecting performance. It lists the main causes contributing to the development of nervous-psychic tension. Furthermore, the works of M. Agadzhanyan, V. Kaznacheev, and S. Kaznacheev identify three qualitatively different types of adaptive human response: "sprinter," "stayer," and "intermediate" types (based on the criterion of time to perform submaximal work). To enhance adaptive abilities, the article proposes the utilization of the bioactivation optimization technique, which effectively enhances a person's psychophysiological functions and meets the requirements for psychophysiological support in military professional activities.

ВЕГЕТАТИВНАЯ ДИСФУНКЦИЯ ПРИ ХРОНИЧЕСКОМ ОПИСТОРХОЗЕ

Introduction. Altai Krai is one of the most significant natural foci of opisthorchiasis not only in Western Siberia, but also on the territory of the Russian Federation as a whole, where the incidence of opisthorchiasis ranges from 44 to 34 per 100,000 people. The primary habitat of opisthorchiasis is the hepatobiliary system; the polymorphism of long-term invasion polymorphism is characterized by a violation of the functions of many organs and systems: liver, immune and cardiovascular systems, digestive organs, etc. The control center responsible for these vital functions of the body is the autonomic nervous system, which regulates them in the body. Analysis of heart rate variability can give an idea of sympathetic-parasympathetic vegetative balance. The purpose of the study. A comprehensive study of the state of autonomic regulation by analyzing heart rate variability in patients with chronic opisthorchiasis. Materials and methods. During the course of the study, 31 patients with chronic opisthorchiasis (CO) were observed, a comparison was made with 30 healthy individuals of similar age and gender. When studying the function of the autonomic nervous system, the method of mathematical analysis of the heart rate according to R.M. Baevsky was used with the help of the original program "CORVEG". The level of critical significance of the null statistical hypothesis was assumed to be 0.05. Results and Discussion. In the study of the nature of vegetative changes, methods of frequency and spectral analysis of heart rate were used. Changes in heart rate regulation indicators were statistically significantly (p<0.05) indicated an increase in sympathetic regulation at rest and orthostasis in patients with SC, their autonomic homeostasis was shifted toward the sympathetic nervous system both at rest and under load, and in some patients (31%) dysregulation of the central type was detected. Conclusions. Dysregulation of autonomic nervous system in patients with chronic opisthorchiasis was revealed at all levels of its regulation and was characterized by increased sympathetic tone and a decrease in parasympathetic and humoral regulation, as well as vasoreflective and baroreflective mechanisms.

ACUTE POST-DYNAMIC, ISOMETRIC AND COMBINED RESISTANCE EXERCISE HYPOTENSION IN PATIENTS WITH HYPERTENSION: A RANDOMIZED STUDY

Objective: American guidelines included dynamic resistance exercise (DRE) and isometric handgrip (IH) in hypertension treatment. A single session of DRE decreases blood pressure (BP) during the recovery period, which has been described as post-exercise hypotension (PEH). However, the occurrence of PEH after a session of IH is controversial and the post-exercise effects of the association of DRE and IH, in a combined resistance exercise (CRE), has not been evaluated. Thus, this study investigated the effects of DRE, IH and CRE on post-exercise BP and its hemodynamic, autonomic and vascular mechanisms. Design and method: Seventy medicated hypertensive men (52 ± 8 years) were randomly allocated to perform 1 of 4 interventions: DRE (8 exercises, 3 sets, 50%1RM, repetitions until moderate fatigue), IH (4 sets, 2 min-unilateral contraction, 30% MVC), CRE (DRE + IH) and control (CO - seated resting). Office BP, systemic hemodynamics (CO2 rebreathing technique), cardiovascular autonomic modulation [spectral analysis of heart rate (HR) and BP variabilities] and brachial vascular parameters (ultrasound) were evaluated before and after the interventions. Thus, the responses to interventions (post – pre-intervention values) were calculated and compared among the groups by ANOVAs with significance level set at P < 0.05. Results: Responses to IH were similar to CO, showing that a single session of IH did not promote PEH, and did not affect any of the BP mechanisms. On the other hand, DRE and CRE induced responses significantly different from IH and CO. DRE and CRE significantly decreased systolic BP, diastolic BP, mean BP, stroke volume and cardiac baroreflex sensitivity, while they significantly increased HR, brachial artery diameter, blood flow and vascular conductance during the post-exercise period. Additionally, DRE significantly decreased post-exercise cardiac vagal modulation (HFR-R, nu) and increased cardiac sympathovagal balance (LF/HF). Conclusions: DRE, but not IH, elicits PEH, which is accompanied by vasodilation and increased HR, via a higher sympathovagal balance and lower baroreflex sensitivity. The addition of IH to DRE, in a CRE, does not potentiate PEH and did not change its mechanisms.

Spectral analysis of cardiovascular oscillations in the 7-day regimen of losartan administration with and without cold stress.

Spectral analysis of heart rate (HR) and blood pressure (BP) variabilities (BPV and HRV) is widely available and utilized in understanding the dynamic cardiovascular autonomic regulation in a variety of pathophysiological conditions. In conscious cold-stressed (CS) rats, we examined the effect of a 7-day regimen administration of losartan, a selective nonpeptide angiotensin AT1 receptor blockade, on BPV and HRV at three frequency components: very-low frequency (VLF), low frequency (LF), and high frequency (HF). Key findings in changes of systolic BP (SBP), HR, and spectral power densities for cardiopulmonary oscillations (HF), sympathetic oscillations (LF), cardiovascular myogenic oscillations (VLF), and overall autonomic activity total power (TP) showed: (I) In the resting PreCS trial, compared with the saline, losartan increased HFBPV, TPHRV, all three HRV frequency powers, and the occurrence of the dicrotic notch (DN). However, it decreased SBP, HR, and the LFBPV frequency power. (II) In the CS trial, losartan significantly decreased SBP and DN occurrence and HR and LF/HFHRV but significantly increased HFHRV, TPBPV, and all three BPV frequency powers. In addition, similar to the saline, losartan showed positively correlated LFBPV and VLFBPV. Conversely, losartan converted the original inverse correlations between LFHRV and LFBPV of CS to a positive correlation. (III) Compared with saline in PreCS and CS trials, losartan detached the corresponding sympathetic oscillations between LFBPV and LFHRV. The overall result indicates that endogenous angiotensin II, through stimulation of the AT1 receptor, augments sympathetic tone but attenuates sympathetic oscillations in rats, particularly under the stressful cooling impacts.

Функціональні можливості серцевого ритму залежно від особливостей вегетативного гомеостазу в дітей молодшого шкільного віку

One of the most common diseases of the cardiovascular system is cardiac arrhythmias. Assessment of the heart rate is one of the obligatory methods of pediatric examination and its deviation from the age norm may indicate a change in the child's health and be one of the first manifestations of the disease. Heart rhythm disturbances accompany various diseases, namely: congenital heart defects, cardiomyopathies, rheumatic and infectious diseases, intoxication, vegetative crises, endocrine diseases, diseases of the nervous system and others. Most often, in children's practice, it is not always possible to establish the cause of heart rhythm disturbances, as well as to classify the presence of organic or functional disorders without conducting morphological studies. Purpose — to study the features of heart rhythm and the state of the autonomic nervous system (ANS) among the children of primary school age with sinus bradycardia. Materials and methods. Children of primary school age with sinus bradycardia were examined (210 children). All children underwent: clinical examination, ECG at rest and after exercise, daily monitoring of ECG and heart rate, echocardiography, cardiointervalography with spectral analysis of heart rate. Results. Assessment of the cardiovascular system among children with bradycardia revealed the following features: 80.0% of children had no complaints, 68.0% of children at the age of 6–7 years and 55.0% of children at the age of 8–10 years had moderate bradycardia, 32.0% of children at the age of 6–7 years and 45.0% of children at the age of 8–10 years had significant bradycardia. After the exercise test, 71.0% of children still had bradycardia, which is typical for children at the age of 9–10 years and 29.0% of children had an acceleration of heart rate above the age norm. Holter monitoring revealed the following cardiac arrhythmias: sinus rhythm driver migration, ectopic rhythm, sinoatrial block, 2 grade atrioventricular block, atrial extrasystole and ventricular extrasystole. Different duration of sinoatrial pauses was detected: in the range from 1300–1400 ms among the most children (78.0%) to 1700–1800 ms among 1.8% of children. Data from spectral analysis of sinus rhythm showed the predominance of parasympathetic nervous system tone among the 84.0% of children, asympathicotonic (40.5%) and normal (44.9%) autonomic reactivity. Conclusions. Examination of the children of the primary school age revealed sinus bradycardia and bradyarrhythmia among the 80.7% of children. Bradyarrhythmia is typical for children at the age of 6–7 years, bradycardia — for children at the age of 9–10 years. Spectral analysis of the ANS showed an imbalance in the regulation of sinus rhythm: the predominance of the parasympathetic link, regardless of the initial state of the ANS and the violation of adaptive mechanisms. According to Holter monitoring, the duration of pauses is longer than normal for the given age (more than 1300 ms) indicates sinus node dysfunction and requires closer monitoring due to the risk of developing sinus node weakness syndrome and other threatening conditions in later life. The research was carried out in accordance with the principles of the Helsinki declaration. The study protocol was approved by the Local ethics committee of all participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors. Key words: children, bradycardia, bradyarrhythmia, vegetative homeostasis.

Effect of ingesting a meal and orthostasis on the regulation of splanchnic and systemic hemodynamics and the responsiveness of cardiovascular α1-adrenoceptors.

Postprandial orthostasis activates mechanisms of cardiovascular homeostasis to maintain normal blood pressure (BP) and adequate blood flow to vital organs. The underlying mechanisms of cardiovascular homeostasis in postprandial orthostasis still require elucidation. Fourteen healthy volunteers were recruited to investigate the effect of an orthostatic challenge (60°-head-up-tilt for 20 min) on splanchnic and systemic hemodynamics before and after ingesting an 800-kcal composite meal. The splanchnic circulation was assessed by ultrasonography of the superior mesenteric and hepatic arteries and portal vein. Systemic hemodynamics were assessed noninvasively by continuous monitoring of BP, heart rate (HR), cardiac output (CO), and the pressor response to an intravenous infusion on increasing doses of phenylephrine, an α1-adrenoceptor agonist. Neurohumoral regulation was assessed by spectral analysis of HR and BP, plasma catecholamine and aldosterone levels and plasma renin activity. Postprandial mesenteric hyperemia was associated with an increase in CO, a decrease in SVR and cardiac vagal tone, and reduction in baroreflex sensitivity with no change in sympathetic tone. Arterial α1-adrenoceptor responsiveness was preserved and reduced in hepatic sinusoids. Postprandial orthostasis was associated with a shift of 500 mL of blood from mesenteric to systemic circulation with preserved sympathetic-mediated vasoconstriction. Meal ingestion provokes cardiovascular hyperdynamism, cardiac vagolysis, and resetting of the baroreflex without activation of the sympathetic nervous system. Meal ingestion also alters α1-adrenoceptor responsiveness in the hepatic sinusoids and participates in the redistribution of blood volume from the mesenteric to the systemic circulation to maintain a normal BP during orthostasis.NEW & NOTEWORTHY A unique integrated investigation on the effect of meal on neurohumoral mechanisms and blood flow redistribution of the mesenteric circulation during orthostasis was investigated. Food ingestion results in cardiovascular hyperdynamism, reduction in cardiac vagal tone, and baroreflex sensitivity and causes a decrease in α1-adrenoceptor responsiveness only in the venous intrahepatic sinusoids. About 500-mL blood shifts from the mesenteric to the systemic circulation during orthostasis. Accordingly, the orthostatic homeostatic mechanisms are better understood.

Quantitative analysis of dysautonomia in patients with autonomic dysreflexia.

Autonomic dysreflexia (AD) is a life-threatening condition for individuals with cervical or high-thoracic spinal cord injury (SCI). The profile of autonomic dysfunction in AD using validated clinical autonomic tests has not been described so far, although it could be useful to identify SCI patients at greater risk of developing AD non-invasively. With this objective, 37 SCI patients (27% female) were recruited, and hemodynamic and cardiac parameters were continuously monitored to determine the presence of AD, defined as an increase of systolic blood pressure of 20mmHg or higher after bladder filling with saline. Then, standard autonomic function testing was performed, including Deep Breathing, Valsalva Manoeuvre and Tilt Table Test. Finally, baroreflex sensitivity (BRS), and spectral analysis of heart rate and blood pressure variability were measured at rest. Catecholamines and vasopressin levels were also measured at supine and upright positions. The severity of SCI was assessed through clinical and radiological examinations. AD was observed in 73.3% of SCI patients, being 63.6% of them asymptomatic during the dysreflexive episode. AD patients displayed a drop in sympathetic outflow, as determined by decreased noradrenalin plasma levels, reduced sympathovagal balance and increased BRS. In line with decreased sympathetic activity, the incidence of neurogenic orthostatic hypotension was higher in AD patients. Our results provide novel evidence regarding the autonomic dysfunction in SCI patients with AD compared to non-AD patients, posing non-invasively measured autonomic parameters as a powerful clinical tool to predict AD in SCI patients.

ТЕОРЕТИЧНІ ЗАСАДИ ОЦІНКИ ТА КОРЕКЦІЇ ФУНКЦІОНАЛЬНИХ СТАНІВ МОЛОДИХ ОФІЦЕРІВ НА ОСНОВІ ВАРІАБЕЛЬНОСТІ СЕРЦЕВОГО РИТМУ

Introduction. The author considers the importance of satisfactory physical condition of young officers during the performance of professional duties. The power of the circulatory system under the influence of loads of different capacities is considered in detail. The relationship between the tension of regulatory systems and the level of blood circulation is shown. Purpose. Identify and characterize the theoretical foundations of assessment and correction of functional states of young officers based on heart rate variability.Methods. Search on the available methodical and scientific literature with the analysis of the found material, clarification of causal relations, systematization, the analysis of documentation and results of activity of researchers on a problem of the spent research. To achieve the goal of the study used theoretical analysis, comparison, generalization and systematization of literature sources, including the study of empirical data on specific issues.Originality. The scientific novelty of the work lies in the availability of original research material in the direction of the study. The practical value lies in the presence of theoretical material on the study, eliminated among other things in the process of finding information on the topic, and in the systematization of the material of the research direction. It is noted that a set of tools should be used to determine a complete picture of the amount of functional reserve. The concept of "heart rate variability" is described. Varieties of methods of analysis of heart rate variability are determined. The peculiarities of the use of the hardware-programmed complex "Fazagraf" in the context of basic parameters are analyzed: standard deflection of RR-intervals, spectral power density in the low-frequency range, intensity index, parameter of spectral analysis of heart rate. The use of cardiointervalography is described. The effectiveness of using the Polar RS800CX remote heart rate monitor and the Polar Pro Trainer software package to obtain heart rate variability is reported. It is stipulated that during the research it is expedient to focus on such indicators as Total Power, High Frequency, Low Frequency, and Very Low Frequency. Three approaches to HRV analysis using geometric methods are characterized: measurement of parameters directly from the constructed geometric figures; approximation of the heart rate pattern through the construction of geometric shapes; direct description and interpretation of the form of constructed geometric figures of heart rhythm. It is noted that the main method of geometric analysis is the construction and analysis of histograms of heart rhythm. The study has a deeper degree of analysis of the research area, based on previous research by scientists, dissertators and researchers.Conciusion. Military-professional activity of young officers is carried out in the conditions of a wide range of factors influencing and is characterized by high physiological "cost" of results of military activity. The technology of diagnostics of the functional state of the body of young officers is proposed, which is a set of physiologically justified structural and functional components.

Effects of nasal high flow on nocturnal hypercapnia, sleep, and sympathovagal balance in patients with neuromuscular disorders

PurposeIn neuromuscular disorders (NMD), inspiratory muscle weakness may cause sleep-related hypoventilation requiring non-invasive ventilation (NIV). Alternatively, nasal high flow therapy (NHF) may ameliorate mild nocturnal hypercapnia (NH) through washout of anatomical dead space and generation of positive airway pressure. Ventilatory support by NIV or NHF might have favourable short-term effects on sympathovagal balance (SVB). This study comparatively investigated the effects of NHF and NIV on sleep-related breathing and SVB in NMD patients with evolving NH.MethodsTranscutaneous CO2 (ptcCO2), peripheral oxygen saturation (SpO2), sleep outcomes and SVB (spectral analysis of heart rate, diastolic blood pressure variability) along with haemodynamic measures (cardiac index, total peripheral resistance index) were evaluated overnight in 17 patients. Polysomnographies (PSG) were randomly split into equal parts with no treatment, NIV and NHF at different flow rates (20 l/min vs. 50 l/min). In-depth analysis of SVB and haemodynamics was performed on 10-min segments of stable N2 sleep taken from each intervention.ResultsCompared with no treatment, NHF20 and NHF50 did not significantly change ptcCO2, SpO2 or the apnea hypopnea index (AHI). NHF50 was poorly tolerated. In contrast, NIV significantly improved both gas exchange and AHI without adversely affecting sleep. During daytime, NHF20 and NHF50 had neutral effects on ventilation and oxygenation whereas NIV improved ptcCO2 and SpO2. Effects of NIV and NHF on SVB and haemodynamics were neutral during both night and daytime.ConclusionsNHF does not correct sleep-disordered breathing in NMD patients with NH. Both NHF and NIV exert no immediate effects on SVB.

Effects of nasal high flow on sympathovagal balance, sleep, and sleep-related breathing in patients with precapillary pulmonary hypertension

BackgroundIn precapillary pulmonary hypertension (PH), nasal high flow therapy (NHF) may favorably alter sympathovagal balance (SVB) and sleep-related breathing through washout of anatomical dead space and alleviation of obstructive sleep apnea (OSA) due to generation of positive airway pressure.ObjectivesTo investigate the effects of NHF on SVB, sleep, and OSA in patients with PH, and compare them with those of positive airway pressure therapy (PAP).MethodsTwelve patients with PH (Nice class I or IV) and confirmed OSA underwent full polysomnography, and noninvasive monitoring of SVB parameters (spectral analysis of heart rate, diastolic blood pressure variability). Study nights were randomly split into four 2-h segments with no treatment, PAP, NHF 20 L/min, or NHF 50 L/min. In-depth SVB analysis was conducted on 10-min epochs during daytime and stable N2 sleep at nighttime.ResultsAt daytime and compared with no treatment, NHF20 and NHF50 were associated with a flow-dependent increase in peripheral oxygen saturation but a shift in SVB towards increased sympathetic drive. At nighttime, NHF20 was associated with increased parasympathetic drive and improvements in sleep efficiency, but did not alter OSA severity. NHF50 was poorly tolerated. PAP therapy improved OSA but had heterogenous effects on SVB and neutral effects on sleep outcomes. Hemodynamic effects were neutral for all interventions.ConclusionsIn sleeping PH patients with OSA NHF20 but not NHF50 leads to decreased sympathetic drive likely due to washout of anatomical dead space. NHF was not effective in lowering the apnea-hypopnoea index and NHF50 was poorly tolerated.

Adaptive servo-ventilation therapy does not favourably alter sympatho-vagal balance in sleeping patients with systolic heart failure and central apnoeas: Preliminary data

BackgroundIn contrast to continuous positive airway pressure (CPAP), the use of adaptive servo-ventilation (ASV) for treatment of central sleep apnoea (CSA) was associated with increased mortality in patients with chronic systolic heart failure (CHF). In order to characterize the interplay between sleep-disordered breathing, CHF and sympathovagal balance (SVB) this study investigated the effect of nocturnal CPAP and ASV on SVB in CSA patients with or without CHF. MethodsThirty-seven patients with ongoing positive airway pressure therapy (CPAP or ASV) for CSA (17 patients with systolic CHF - left ventricular ejection fraction <50% - and 20 patients with CSA but no CHF) underwent evaluation of SVB (spectral analysis of heart rate -HRV- and diastolic blood pressure variability) during full nocturnal polysomnography. The night was randomly split into equal parts including no treatment (NT), automatic CPAP and ASV. Data analysis was restricted to stable N2 sleep. ResultsIn patients with CSA and systolic CHF, neither automatic CPAP nor ASV showed favourable effects on parameters reflecting SVB during N2 sleep (all p > 0.05). In contrast, in subjects with CSA without CHF automatic CPAP, but not ASV, favourably altered SVB by decreasing the low frequency and increasing the high frequency component of HRV (both p = 0.03). ConclusionsEffects of various modes of positive airway pressure therapy of CSA on SVB during sleep depend on the mode of pressure support and underlying cardiac function. Automatic CPAP but not ASV favourably influences SVB in subjects without CHF, whereas both interventions leave SVB unchanged in patients with CHF.

Effectiveness of Respite Care via Short-Stay Services to Support Sleep in Family Caregivers.

Family caregivers of older people who need care often experience sleep disorders, which can lead to various health problems. Although respite care is used in many countries, its effectiveness has not been fully demonstrated. We analyzed the sleep of family caregivers using actigraphy and heart rate spectral analysis to clarify changes in their sleep characteristics during short-stay respite care. Participants were all family caregivers living with an older person needing long-term care. The outcomes consisted of questionnaire responses, sleep/wake records, and R-wave to R-wave interval records. Quantitative evaluation of sleep revealed that caregivers’ median sleep time was 378.0 min, and median sleep efficiency was 94.7%. The low frequency (LF)/high frequency (HF) value was 1.722 for total sleep and 1.822 for the first half of the sleep period. The LF/HF for the first half of the sleep period was significantly different between caregiving and respite days. The respite day LF/HF was 1.567, which was significantly lower than on caregiving days. On respite days, cardiac sympathetic nervous activity among family caregivers was reduced during the first half of the sleep period. This suggests that regular use of short-stay services can improve caregivers’ sleep status, making this an effective form of respite care.

A Novel Approach in Spinal Cord Stimulation for Enhancing Gastric Motility: A Preliminary Study on Canines.

Background/AimsGastroparesis is commonly seen in patients with diabetes and functional dyspepsia with no satisfactory therapies. Dysautonomia is one of the main reasons for the imbalanced motility. We hypothesized that spinal cord stimulation (SCS) is a viable therapy for gastroparesis via the autonomic modulation to improve gastric motility. The aim is to find an optimal method of SCS for treating gastroparesis.MethodsEight healthy-female dogs were implanted with a gastric cannula, a duodenal cannula, 2 multi-electrode spinal leads, and an implantable pulse generator. Gastric motility index (MI) was used to determine the best stimulation location/parameters of SCS. Optimized SCS was used to improve glucagon-induced gastroparesis.ResultsWith fixed parameters, SCS at Thoracic 10 (T10) was found most effective for increasing gastric MI (37.8%, P = 0.013). SCS was optimized with different parameters (pulse width: 0.05–0.6 msec, frequency: 5–500 Hz, motor threshold: 30–90%) on T10. Our findings revealed that 0.5 msec, 20 Hz with 90% motor threshold at T10 were the best parameters in increasing MI. Glucagon significantly delayed gastric emptying, and this inhibitory effect was partially blocked by SCS. Gastric emptying at 120 minutes was 25.6% in the control session and 15.7% in glucagon session (P = 0.007 vs control), while it was 22.9% with SCS session (P = 0.041 vs glucagon). SCS with the optimal parameters was found to maximally enhance vagal activity and inhibit sympathetic activity assessed by the spectral analysis of heart rate variability.ConclusionsSCS with optimized stimulation location and parameters improves gastric motility in healthy-dogs and accelerates gastric emptying impaired by glucagon via enhancing vagal activity.

Abstract P3057: Slow Breathing Training Reduces Blood Pressure in Healthy Normotensive Subjects

Slow breathing, an integral part of different body mind relaxation practices, might modulate autonomic tone and lower bp. It is unknown if extended exhalation technique (E&gt;I) will have different effects than common slow breathing (E=I). We hypothesized that E&gt;I will have a greater impact on blood pressure. We studied 86 healthy participants (41±4 years, 76% female) randomly assigned to E=I (n=41) or E&gt;I (n=45) daily exercise guided by Yoga teachers over 12 weeks. We measured blood pressure, autonomic tone by spectral analysis of heart rate and blood pressure variability and cardio-vagal baroreflex sensitivity by spontaneous sequence technique (BRS) at baseline and at 12 weeks. For comparison, we included two groups without breathing interventions: normotensives (NTN), n=14 SBP 114± 5 mm Hg and hypertensives (HTN), n=15 SBP 141± 3 mm Hg, that were studied on two separate visits at least one month apart. SBP significantly decreased at 12 weeks for both intervention groups, 3.5 ± 6.6 mm Hg for E&gt;I (p&lt;0.001) and 3.5 ± 5.5 mm Hg for E=I (p&lt;0.001). No differences were found between groups or for the controls. The blood pressure drop was significantly greater among subjects with higher initial SBP [SBP=123±2 mm Hg, n=24, (HBP)] as compared with lower SBP [SBP=96±1 mmHg, n=24 (LBP)]: SBP changed 6.3 ± 7.3 mm Hg (p&lt;0.001) for HBP, with no significant drop for LBP (figure). BRS changed differently by time and group with increase in E&gt;I (E&gt;I: 3.07±1.2 ms/mmHg, E=I:-0.24±0.8 ms/mmHg, p(time)=0.013, p(timeXgroup)=0.019.In conclusion, 12 weeks of slow breathing exercises resulted in a significant reduction of blood pressure and changes in baroreflex sensitivity independently of the type of breathing.

Identifying an optimal epoch length for spectral analysis of heart rate of critically-ill infants

Background and objectiveTo identify the optimal epoch length for power spectral analysis of cardiac beat-to-beat intervals (BBi) in critically ill newborns. Materials and methodBBi of 49 term newborns undergoing therapeutic hypothermia for hypoxic-ischemic encephalopathy with well-defined outcomes (good outcome (n = 28): no or mild brain injury and adverse outcome (n = 21): moderate or severe brain injury or death) served as test population. A power spectrum of BBi was calculated with an autoregressive model in three different epoch lengths: 2 min, 5 min, and 10 min. Spectral power was quantified in three different frequency bands: very low-frequency (0.016–0.04 Hz), low-frequency (0.05–0.25 Hz), and high-frequency (0.3–1 Hz). In each frequency band, the absolute power and the normalized power were calculated. Furthermore, standard deviation (SDNN) of BBi was calculated. These metrics were compared between the outcome groups with a receiver operator characteristic (ROC) analysis in 3-h windows. The ROC curve area >0.7 was regarded as a significant separation. ResultsThe absolute spectral powers in all three epoch lengths in all three frequency bands and SDNN distinguished the two outcome groups consistently for most time points. The spectral metrics calculated with a 2-min epoch length performed as well as the five- and 10-min epoch lengths (paired t−test P < 0.05). ConclusionSpectral analysis of BBi in 2-min epoch shows a similar discriminatory power as longer epoch lengths. A shorter epoch also has clinical advantages for translation into a continuous real-time bedside monitor of heart rate variability in the intensive care unit.

Reactivity of cardiorespiratory system in bronchial asthma patients according to the tests with respiratory maneuvers performance

Today asthma is defined as allergic inflammation of the respiratory tract, which is associated with hyperreactivity of the bronchi to various stimuli. The basis of asthma clinical picture forms broncho-obstructive syndrome, which is polymorphic in the mechanism of formation, and this determines the heterogeneity of asthma pathogenesis. Due to the anatomical and functional relationship with the cardiovascular system, this mechanism should be considered in a complex manner studying the composition changes in the associated cardiopulmonary system.The objective: to determine the regulatory features in asthma course of various degrees of severity during respiratory maneuvers performance.Materials and methods. In total, 86 patients (female (59 %) and male (41 %)), aged 41.0 ± 0.8 years old were divided into 2 groups. The first (comparison group) included 27 patients, the second (main) consisted of 59 patients with clinically confirmed persistent or uncontrolled asthma. At the outpatient stage of treatment, a comprehensive multifunctional method for the cardiorespiratory system examination – spiroarteriocardiorhythmography (SACR) was used. There were three consecutive two-minute registrations: at normal respiration (NR), at respiratory rate 6 times per minute (RR6) and at respiratory rate 15 times per minute (RR15). Regulatory influences were determined based on the spectral analysis of heart rate (HRV) and respiration (RV) variability. Spectral analysis was performed in three frequency bands: over low-frequency (VLF, 0–0.04 Hz), low frequency (LF, 0.04–0.15 Hz) and high-frequency (HF, 0.15–0.4 Hz).Results. Cardiorespiratory system of patients with uncontrolled course of asthma is characterized by an increase in heart rate at RR15; reduced absolute HRV indicators; an increase in the contribution of LFn and a decrease in the contribution of HFn; a decrease in the arterial baroreflex sensitivity; an increase in EB; there was also an increase in RV, RV/Tih, RV/Texh, as well as worsening of frequency and volume synchronization of the cardiorespiratory system.Conclusions. The use of respiratory maneuvers performance tests allowed revealing the characteristic regulatory features of bronchial asthma development and course, so it can be proposed for wide practical implementation in the diagnosis and monitoring of bronchial asthma course.

The Effect of Breathing at the Resonant Frequency on the Nonlinear Dynamics of Heart Rate

Investigation of the nonlinear dynamics of the heart rate is crucial for understanding the physiological mechanisms of various functional states and understanding the adaptation capacity of the human body. The purpose of this study was to evaluate some quantitative parameters of the nonlinear parameters of resonance in the heart rate variability. The study included 70 healthy students who underwent paced breath training. The heart rate was recorded during breathing at different respiratory rates (spontaneous breathing, 4.5, 5, 5.5, 6, and 6.5 breaths/min). The resonant frequency was determined using heart-rate spectral analysis. Nonlinear analysis of HRV was performed using entropy measures (ApEn, SampEn, and MSE), Correlation dimension, Detrended Fluctuation Analysis (DFA), Recurrence Plot (REC, DET, Lmean, Lmax, and ShanEn), the Poincare plot (SD1 and SD2), and time asymmetry (GI and P). We observed a decrease in the level of complexity, an increase in the self-similarity of the RR intervals, a decrease in the chaotic component, and an increase in rhythm asymmetry during breathing at resonant frequency.