Regulation Of Heart Rhythm Research Articles

Effect of Lead, Cadmium, and Their Combination on the Heart Rate Regulation in Nonlinear Rats.

We studied heart rate variability (HRV) and the concentrations of heavy metals in the heart tissue after 14-fold peroral administration of heavy metal salts: lead acetate (50 mg/kg), cadmium chloride (5 mg/kg), and their combination. After administration of lead, its concentration in the myocardium exceeded the control values by 1.2 times or did not change in case of combination with cadmium; after administration of cadmium, its concentration in the myocardium exceeded the control value by 6.1 times or by 2 times after combined administration. After lead administration, a moderate increase in HR, low values of stress and centralization indices, and an increase in the power in all ranges of the HRV spectrum were recorded. After cadmium intoxication, a tendency to a decrease in heart rhythm variability, a moderate increase in HR, stress and centralization indices, and an increase in the contribution of VLF waves in the HRV spectrum were observed. After combined administration, a pronounced increase in HR and stress index and a moderate increase in the centralization of heart rhythm control were recorded, which was similar to changes in HRV observed after administration of cadmium alone. In the experiment, the concentration of cadmium in the myocardium increased to a much greater extent than the concentration of lead. After lead administration, the autonomous type of regulation persisted and parasympathetic influences increased. Cadmium apparently acts as a stress factor and increases the role of sympathoadrenal influences and central ergotropic structures in the heart rhythm regulation.

Adaptive responses of heart rate regulation during functional tests with breath holding

BACKGROUND: Synchronization of biorhythms in living organisms is of particular interest to researchers from the standpoint of adaptation theory. AIM: To study the characteristics of the response of regulatory influences on heart rhythm during tests with voluntary breath holding during inhalation and exhalation. MATERIAL AND METHODS: The study sample included 21 randomly selected students (9 males, 12 females) aged 20.64±1.14 years with body weight 67.19±12.98 kg, height 172.29±7.63 cm. All subjects were divided into three groups (I, II, III) according to the classification by N.I. Shlyk (2009), which is based on the predominance of central or autonomic circuits of heart rhythm regulation. A fivefold sequential ECG recording was conducted using the hardware-software complex “Varicard 3.0” with the subject seated after a five-minute rest: 1 — baseline state; 2 — voluntary breath holding during inhalation; 3 — resting state; 4 — voluntary breath holding during exhalation; 5 — resting state. Using the “Varicard 3.0” system, a mathematical analysis of heart rhythm was performed, taking into account statistical parameters of heart rhythm and indices of spectral frequency analysis. RESULTS: During the period of breath holding, heart rate variability decreased, while at rest it increased in all groups. In group I, after a breath-hold test during the rest period, eutonia was observed according to spectral analysis (HF=LF). Statistical analysis in this group demonstrated an increase in the contribution of the parasympathetic component to heart rate variability (RMSSD, pNN50, SDNN, CV), signifying the prerequisites for increased heart rate variability. In group II, after breath-holding tests, a slight decrease in sympathetic activity was observed. A tense pattern of autonomic regulation was observed during the exhalation breath-hold test, which may indicate a reduced functional state of the regulatory systems. Group III was characterized by a sharp increase in sympathetic activation in the test with breath holding during inhalation, followed by a soft correction during breath holding during exhalation, which can be regarded as an adequate response of the body to the load. At rest, after the test, the regulation pattern returned to the original one with a moderate predominance of parasympathetic activity and, accordingly, a more favorable level of heart rate variability for the body. CONCLUSION: Adaptive reactions of the heart rate variability are manifested by an increase in sympathetic activation, which, subsequently, during normal breathing, is replaced by a compensatory activation of the parasympathetic division of the autonomous nervous system. Although reactions are unidirectional, the severity can vary across the groups.

The role of morphofunctional asymmetries of the female body in the autonomic regulation of heart rate during menopause

The aim of the work was to study the features of autonomic regulation of heart rhythm (HR) in women in the peri- and postmenopausal periods, depending on morphofunctional asymmetries of the female body. A total of 417 women aged 35–60 were examined. According to the lateral behavioral profile of asymmetries of the female body (Annette’s test), the nature of vegetative regulation at rest and orthostasis was determined according to the data of cardiac intervalography using the Varicard 2.51 complex and the Eskim-6 program. As a result, it was found that in the reproductive period in women with the right lateral phenotype, the autonomous circuit of HR variability regulation prevailed, and in ambidextrous women, the central one dominated. Ambidextrous and right-handers were characterized by egalitarian modulation, while left-handers were characterized by a respiratory typology of autonomic regulation of HR. In perimenopause, a moderate tension of regulatory mechanisms was formed in the lateral subgroups, and a high tension was formed in the postmenopausal subgroups. In ambidextrous and left-handers, discoordination of HR regulation prevailed. Thus, women with the polarity of the lateral phenotype in the late reproductive period were distinguished by the stability and economy of the mechanisms of autonomic regulation of HR. Ambidextrous had the most energy-consuming mechanisms in the postmenopausal period, which is a risk of cardiovascular disease pathology.

High plasticity of temperament as a marker of flexible autonomic regulation of the cardiovascular system in urgent adaptive response to cold in young people

The properties of temperament are due to differences in the excitability of brain systems that integrate the behavior of an individual, his emotions and autonomic functions and play an important role in the adaptation of the body to the environment. The mechanisms of the relationship between individual characteristics of temperament properties and regulation of the cardiovascular system have not been fully elucidated. The aim of this study to assess the relationship between expression of temperament traits and the autonomic regulation of the cardiovascular system in the baseline condition and in response to exposure to cold. The study involved 25 healthy male volunteers aged between 18 and 21 years. Temperament traits were measured using the Structure of Temperament Questionnaire. During the study, heart rate variability (HRV) parameters (5 min), systolic and diastolic blood pressure (SBP and DBP) were recorded at room temperature. In the period from 5 to 10 min of exposure in an UShZ-25 N cold chamber (–20 °C), HRV were assessed. Immediately after the subjects came out from the cold chamber, blood pressure was measured. Then, 5 min after they left the cold chamber, SBP, DBP, HRV were recorded. The results showed that in young people with different expressions of temperamental properties, no differences were found in the regulation of heart rhythm by the autonomic nervous system in the baseline condition. The high object-related plasticity, i.e. the ease of switching from one type of activity to another, linked with autonomic flexibility and blood pressure control, which restrains a significant increase in blood pressure when exposed to short-term cold, and contributes to the preservation of health.

The change in Baroreflex Regulation of Heart Rhythm after “Dry” Immersion Appears during Orthostasis, but not Lower Body Negative Pressure Test

The ratio of low-frequency (LF, ~0.1 Hz) waves of RR interval duration (RRI) and systolic blood pressure (SAP) reflects the cardiac baroreflex sensitivity (BRS). Gravitational unloading (GU) may alter BRS during the passive orthostatic test (HUT) and lower body negative pressure (LBNP) test. Both effects cause blood redistribution to the lower body, but HUT is accompanied by greater unloading of sinocarotid baroreceptors than LBNP and activation of the vestibulosympathetic reflex but GU effects on BRS in these tests have not been directly compared previously. In this study we tested the hypothesis that the effect of “dry” immersion (DI, on-ground model of GU) on BRS in the same subjects will be more pronounced during HUT than during LBNP, which causes a comparable decrease in stroke volume. Nine healthy men participated in two test sessions (before and after 7-day DI) consisting of five 3-min HUT (65°) and five 3-min LBNP (–35 mmHg) with averaging the parameters in each test. Wavelet analysis was used to determine the amplitude of the RRI and SAP waves in the range of 0.05–0.13 Hz. The amplitude of LF waves of SAP increased in both tests, after DI - more significantly in HUT. The amplitude of LF RRI waves decreased in the two tests; the degree of decrease did not differ between tests and did not change under the influence of DI. The α-coefficient (the ratio of the amplitudes of RRI and SAP LF waves) decreased equally in the two tests before DI, but after DI, the degree of α-coefficient reduction increased in HUT test but did not change in LBNP test. Thus, the effect of DI on BRS is evident in HUT, but not in LBNP, which may be explained by the more pronounced influence of HUT on the mechanisms of neural control of heart rhythm.

Study of heart rate variability to assess the autonomic nervous system functioning in women with different degrees of obesity

In recent decades, there has been a significant increase in obese people worldwide. There is a large number of hypotheses describing the causes of the development of obesity, but few studies have addressed changes arising in the autonomic nervous system. The predominance of the sympathetic nervous system could potentially be a leading link in the pathogenesis of the development of cardiovascular complications in obesity. The aim of the study was to investigate the relationship between the ANS circuit and body weight, with age. In our work, 161 women were examined using spectral analysis of the hardware and software complex «Omega-M». Then the participants were distributed into groups according to age and body weight. Statistical grouping and data processing were carried out using Microsoft Office software package. After analyzing the group «40–49 years old», it has been revealed that the central regulation in the studied women with the 1st degree of obesity is observed in 67 % of cases, and in the women with the 2nd degree, this type of regulation prevails completely (p=0.0011). In the group «50–59 years old», the women with the 2nd degree of obesity completely lack the autonomous regulation; the central type makes up 89 % of the total number of those examined, while the intermediate type accounts for 11 % (p=0.0042). In the group «60–69 years old» in the women with normal body weight, the central regulation prevails in 83 % of cases. In the group with the 1st degree of obesity, all women have the central regulation (100 %), as in the group with the 2nd degree of obesity, where the central regulation also predominates at 92 %, while the autonomous regulation is found only in 8 % of the examined (p=0.0141). It was noted that in the women with the 2nd degree of obesity, the central regulation of heart rhythm prevails. In the group «60–69 years», this type of regulation begins to prevail regardless of body weight. Thus, with age and with increasing body weight, the predominance of the central regulation of heart rhythm is observed. The dependence of the predominant regulation circuit and age is associated with a decrease in physiological reserves in case of excessive body weight, which may cause the development of cardiovascular diseases and requires the search for effective etiopathogenetic methods of treatment.

Влияние загрязнённой радионуклидами среды на сердечный ритм детей в современных условиях

The main aim was to study the characteristics of heart rate variability in 8- and 10-year boys and girls that permanently reside in areas with an increased level of radioactive contamination. The body functions are formed by close interaction of the body and the environment. The adaptive responses of the developing organism are improved at each ontogenetic stage as its contact with the environment become more complex. We found that features of heart rate regulation depend on the area of residence. The contribution of the autonomous circuit of heart rate regulation is increased for 8- and 10-year-old girls from radio-ecologically safe areas (RESA). Based on the principle of functional antagonism this leads to a weakening of the central circuit of regulation. The shift gradient of indicators is higher for 8-year-old girls from radio-ecologically unfavorable areas (REUA) compared to 10-year-old girls. This reflects the greater sensitivity of their organism to adverse factors. The dominance of the autonomous circuit of regulation was marked for 8- and 10-year-old boys from the RESA. In contrast an imbalance in the operation of regulatory mechanisms with an increase in the central regulatory circuit was found for boys from the REUA. High centralization of cardiac control indicates that adaptation mechanisms are in a state of pronounced tension. The increase in the shift gradient for boys from REUA falls at the age of 10 years. The results of the study revealed gender differences in the regulation of heart rhythm. The obtained data is important diagnostic aspects of morphofunctional maturation of the organism for subsequent ontogenetic stages depending on environmental living conditions.

Acute myocardial infarction in patients with concomitant hypothyroidism: clinical features and heart rate variability during inpatient treatment

Objective: to evaluate the features of the clinical course, as well as heart rate variability (HRV) during inpatient treatment in patients with ST-segment elevation myocardial infarction (STEMI) and concomitant newly diagnosed hypothyroidism.Materials and methods: the study included 133 patients with STEMI aged 40 to 88 years who were admitted to the cardiology department. Depending on the presence of newly diagnosed hypothyroidism syndrome, all patients were divided into 3 groups: group 1 consisted of patients with STEMI without hypothyroidism syndrome (n=57), group 2A — patients with STeMI and subclinical hypothyroidism (n=42) and group 2B — patients with STeMI and manifest hypothyroidism (n=34). Clinical symptoms and complications in the acute period of MI were evaluated in all patients, and Holter ECG monitoring (XM ECG) was performed.Results: during hospital treatment, patients with concomitant manifest hypothyroidism showed more frequent development of cardiac arrhythmias such as paroxysmal atrial fibrillation (AF) (p<0.05), supraventricular extrasystole (NE), paroxysmal supraventricular tachycardia (LVT) (p<0,05). When assessing the risk of early complications in the acute period of MI, higher scores were recorded in patients with manifest hypothyroidism (p<0.05). The analysis of HRV indicators showed that in the studied patients with concomitant manifest hypothyroidism, despite the presence of an acute period of MI, activation of the parasympathetic link of the ANS (autonomic nervous system) prevails in the regulation of heart rhythm, unlike in patients of the control group and the group with subclinical hypothyroidism, in whom, on the contrary, the influence of the sympathetic link of the ANS prevails.Conclusion: during hospitalization, patients with manifest hypothyroidism were statistically significantly more likely to develop supraventricular cardiac arrhythmias, and a higher risk of cardiovascular complications in the acute period of MI was determined compared with both the control group and the group of patients with subclinical hypothyroidism. In patients with concomitant manifest hypothyroidism, the activation of the parasympathetic link of the ANS in the regulation of heart rhythm is more pronounced, in contrast to patients in the control group and the group with subclinical hypothyroidism, in whom, on the contrary, the influence of the sympathetic link of the ANS prevails.

ScRNA-seq reveals the diversity of the developing cardiac cell lineage and molecular players in heart rhythm regulation

We utilized scRNA-seq to delineate the diversity of cell types in the zebrafish heart. Transcriptome profiling of over 50,000 cells at 48 and 72 hpf defined at least 18 discrete cell lineages of the developing heart. Utilizing well-established gene signatures, we identified a population of cells likely to be the primary pacemaker and characterized the transcriptome profile defining this critical cell type. Two previously uncharacterized genes, atp1b3b and colec10, were found to be enriched in the sinoatrial cardiomyocytes. CRISPR/Cas9-mediated knockout of these two genes significantly reduced heart rate, implicating their role in cardiac development and conduction. Additionally, we describe other cardiac cell lineages, including the endothelial and neural cells, providing their expression profiles as a resource. Our results established a detailed atlas of the developing heart, providing valuable insights into cellular and molecular mechanisms, and pinpointed potential new players in heart rhythm regulation.

Особливості психічного стану у кваліфікованих борців

Purpose: research of psychical state in qualified wrestlers in stage of special basic fitness. Material and methods. The study involved 31 skilled Greco-Roman wrestlers aged 14-16 years, pupils of the wrestling club in Kremenchuk. To assess the mental state of skilled wrestlers, the Luscher color test was used. According to the results of the study, the following indicators were obtained: performance, fatigue, anxiety, deviation from the autogenous norm, eccentricity, concentricity, vegetative coefficient, heteronomy and autonomy. Heart rate variability was studied as an indicator of mental stress. The cardiac monitor «Fazagraf» was used. Based on the results of the study, we obtained statistical processing indicators and spectral characteristics of cardiac intervals. Non-parametric statistics with the determination of the median, lower and upper quartiles were used to assess the differences between the studied parameters. Results: in wrestlers with high tension of the autonomic regulation system, a deterministic functional system aimed at ensuring the mental state is revealed. At the same time, an increase in the tension of autonomic regulation is accompanied by mental fatigue, anxiety, passivity and the presence of mental stress. Prevention of mental stress in skilled wrestlers may be associated with the activation of the athlete to external environmental stimuli, optimism and a mood for positive behavior. The relationship between the indicators of mental state and the parameters of mental functions in skilled wrestlers was revealed. The moderate tension of the heart rate regulation system in skilled wrestlers is accompanied by an increase in mental performance and a decrease in anxiety. In turn, the increase in the tension of autonomous regulation is reflected in the presence of internal psychological discomfort and independence in the formation of decision-making. However, there is an increase in anxiety and a decrease in mental performance. Conclusions. The relationship between indicators of mental state and parameters of psychical functions in qualified wrestlers was revealed. Moderate tension of the heart rhythm regulation system in qualified wrestlers is accompanied by an increase in mental capacity and a decrease in anxiety. The increase in the tension of autonomous regulation in qualified wrestlers is reflected in the presence of internal psychological discomfort and independence in decision-making. Keywords: mental state, qualified wrestlers, heart rate regulation, indicators, analysis.

Using heart rate variability to develop a predictive model for post-operative cardiovascular complications following major abdominal surgery: A pilot study.

Heart Rate Variability (HRV) is a dynamic reflection of heart rhythm regulation by various physiological inputs. HRV deviations have been found to correlate with clinical outcomes in patients under physiological stresses. Perioperative cardiovascular complications occur in up to 5% of adult patients undergoing abdominal surgery and are associated with significantly increased mortality. This pilot study aimed to develop a predictive model for post-operative cardiovascular complications using HRV parameters for early risk stratification and aid post-operative clinical decision-making. Adult patients admitted to High Dependency Units after elective major abdominal surgery were recruited. The primary composite outcome was defined as cardiovascular complications within 7days post-operatively. ECG monitoring for HRV parameters was conducted at three time points (pre-operative, immediately post-operative, and post-operative day 1) and analyzed based on outcome group and time interactions. Candidate HRV predictors were included in a multivariable logistic regression analysis incorporating a stepwise selection algorithm. 89 patients were included in the analysis, with 8 experiencing cardiovascular complications. Three HRV parameters, when measured immediately post-operatively and composited with patient age, provided the basis for a predictive model with AUC of 0.980 (95% CI: 0.953, 1.00). The negative predictive value was 1.00 at a statistically optimal predicted probability cut-off point of 0.16. Our model holds potential for accelerating clinical decision-making and aiding in patient triaging post-operatively, using easily acquired HRV parameters. Risk stratification with our model may enable safe early step-down care in patients assessed to have a low risk profile of post-operative cardiovascular complications.

Fuzzy-Based Bioengineering System for Predicting and Diagnosing Diseases of the Nervous System Triggered by the Interaction of Industrial Frequency Electromagnetic Fields.

The study aims to enhance the standard of medical care for individuals working in the electric power industry who are exposed to industrial frequency electromagnetic fields and other relevant risk factors. This enhancement is sought through the integration of fuzzy mathematical models with contemporary information and intellectual technologies. The study addresses the challenges of forecasting and diagnosing illnesses within a specific demographic characterized by a combination of poorly formalized issues with interconnected conditions. To tackle this complexity, a methodological framework was developed for synthesizing hybrid fuzzy decision rules. This approach combines clinical expertise with artificial intelligence methodologies to promote innovative problem-solving strategies. Additionally, the researchers devised an original method to evaluate the body's protective capacity, which was integrated into these decision rules to enhance the precision and efficacy of medical decision-making processes. The research findings indicate that industrial frequency electromagnetic fields contribute to illnesses of societal significance. Additionally, it highlights that these effects are worsened by other risk factors such as adverse microclimates, noise, vibration, chemical exposure, and psychological stress. Diseases of the neurological, immunological, cardiovascular, genitourinary, respiratory, and digestive systems are caused by these variables in conjunction with unique physical traits. The development of mathematical models in this study makes it possible to detect and diagnose disorders in workers exposed to electromagnetic fields early on, especially those pertaining to the autonomic nervous system and heart rhythm regulation. The results can be used in clinical practice to treat personnel in the electric power industry since expert evaluation and modeling showed high confidence levels in decision-making accuracy.

The Change in Baroreflex Regulation of Heart Rhythm after “Dry” Immersion Appears during Orthostasis, but not Lower Body Negative Pressure Test

The Change in Baroreflex Regulation of Heart Rhythm after “Dry” Immersion Appears during Orthostasis, but not Lower Body Negative Pressure Test

Study of the functional state of the cardiovascular system in athletes of cyclic and acyclic kinds of sports

The study was aimed at investigating the influence of sports physical activity on the state of the cardiovascular system in students of cyclic (athletics) and acyclic (judoka) sports. Analysis of heart rhythm has revealed the economization of cardiovascular system functions at rest in the majority of qualified athletes. Heart rhythm control was balanced and regulated by the sympathetic and parasympathetic sections of the autonomic nervous system. Athletes under the influence of cyclic sports physical loads had an increase in the activity of the parasympathetic autonomic nervous system and a moderate level of sympathetic and humoral-metabolic influences on the heart rhythm in comparison with non-athletes. Activation of the autonomic nervous system activity on heart rate in track and field athletes and judokas at rest reflects a significant adaptation of the cardiovascular system to physical activity in athletes. The increase in the activity of the autonomous circuit of heart rhythm regulation in track and field athletes and judoists in resting conditions was an indicator of a significant adaptive potential of the cardiovascular system.

Influence of experimental heart failure therapy with different generations of β-adrenergic blockers on Cardiac Electrical Activity (ECG) and Autonomic Regulation of Heart Rhythm (ARHR)

Abstract: In the complex treatment of chronic heart failure (CHF) β-adrenoblockers (carvedilol, nebivolol, bisoprolol, metoprolol) are used, which due to their pharmacological properties increase the survival rate of patients, improve cardio- and haemodynamic parameters, metabolism. However, modern realities in medicine require creation of new more effective and safe β-adrenoblockers. In this regard, the potential drug Hypertirl is of interest. The aim was to evaluate the cardioprotective effect of 1-(b-phenylethyl)-4-amino-1,2,4-triazolium bromide (Hypertril) on cardiac electrical activity and autonomic regulation of heart rhythm in a model of CHF in comparison with β-adrenoblockers of different generations (Nebivolol, Carvedilol, Bisoprolol, Metoprolol). Materials and methods: Chronic heart failure was induced by 14-day administration of doxorubicin in a cumulative dose of 15 mg/kg to white mongrel rats weighing 190–220g (total 85). The investigated drugs were administered after doxorubicin course for 30 days: Hypertril at an experimentally substantiated dose of 3.5 mg/kg, Metoprolol succinate 15 mg/kg, Nebivolol 10 mg/kg, Carvedilol 50 mg/kg, Bisoprolol 10 mg/kg. At the end of drug administration under thiopental anaesthesia (40 mg/kg), electrocardiogram (ECG) and autonomic regulation of heart rhythm (ARHR) were analysed using a computer analyser CardioCom-2000plus (KAI-Medica, Ukraine). The results of the study were calculated using a standard statistical package “STATISTICA for Windows 6.0” (StatSoftInc., №AXXR712D833214FAN5), “SPSS 16.0” and “Microsoft Office Excell 2003”. Results and discussion: Hypertril administration resulted in a negative chronotropic effect, normalisation of atrial (P) and ventricular (R) spike amplitude, ST segment inversion below isoline, increased amplitude of ventricular myocardial repolarisation T. Myocardial repolarisation spike were observed, as well as normalised the duration of atrial (P) and ventricular depolarisation phase (QRS complex) to the intact value and restored the duration of electrical diastole (TR interval). Hypertril reduced systolic and diastolic myocardial dysfunction in animals with CHF. Hypertril restored autonomic mechanisms of heart rhythm regulation and balanced activity of sympathetic and parasympathetic parts of autonomic nervous system in the control of cardiac function. Conclusion: The obtained results demonstrated the undoubted advantage of the new original molecule (Hypertril) over basic β-adrenoblockers (Metoprolol, Nebivolol, Carvedilol and Bisoprolol) and experimentally justify further in-depth study to create on its basis a drug for the treatment of CHF.

Response of the cardiovascular system to heart rate variability biofeedback intervention in adolescents with different autonomic nervous tone living in northern and southern regions

BACKGROUND: The cardiovascular responses of adolescents during self-regulation are contingent upon their initial autonomic tone and place of residence.
 AIM: To investigate the dynamics of cardiovascular system indices during heart rate variability biofeedback (HRV BF) training in adolescents with different initial autonomic regulation of heart rhythm, taking into account their residence in the northern and southern regions.
 MATERIAL AND METHODS: Schoolchildren aged 1617 years, residents of the northwestern (n=55), northeastern (n=55) and southern (n=55) regions of the Russian Federation were examined. Heart rate variability (HRV) and blood pressure (BP) were recorded. Participants were divided into the following groups according to their baseline autonomic regulation of cardiac rhythm: vagotonics, normotonics and sympathotonics. Normotonics and sympathotonics additionally had a one-time HRV BF session to increase parasympathetic influences on heart rhythm.
 RESULTS: The northwestern/northeastern/southern samples revealed 29/7/16% vagotonics; 42/47/49% normotonics; and 29/46/35% sympathotonics. BP was significantly greater in sympathotonics compared to vagotonics and normotonics in in the northeastern region and sympathotonics in the northwestern and southern regions. HRV BF training was successful in all participants: HRV parameters responded to a greater extent in sympathotonics living in the northwestern region while their BP and baroreflex levels were relatively stable. Sympathotonics of the northeastern and southern regions were characterized by preservation of elevated HR after HRV BF accompanied by a significant decrease in BP and a pronounced baroreflex response.
 CONCLUSION: In the northwestern region, adolescents who are mainly decendants of migrants from the southern regions typically have sympathicotonia and increased vascular response to HRV BF. The descendants of natives of the northwestern region apparently inherited more advanced mechanisms of cardiovascular regulations in the conditions of the Arctic.

Comparative Analysis of Disorders of Heart Rhythm Regulation Mechanisms Induced in Newborn Rats by Nickel Chloride and the Acetylcholinesterase Inhibitor Physostigmine (Eserine)

A comparative analysis of heart rate variability (HRV) indices after injection of the acetylcholinesterase inhibitor (AChE) physostigmine (¾ LD50) and the T-type calcium channel blocker (T-VDCC) Ni2+ (ED100) into animals was performed in experiments on 3-day-old newborn rats. Both drugs cause phenomenologically similar pathological heart rhythm with significant bradycardia complexes (PHRBC). Analysis of HRV indices showed that the disturbance of heart rhythm regulation mechanisms in NiCl2 poisoning of rats and in cholinoreactive structure activation caused by AChE inhibition develop according to a similar pattern. In both cases there is a decrease in the total power of the spectrum and the absolute power values of the LF (predominantly sympathetic) and HF (parasympathetic influences) bands. Significant decrease in the level of nerve influences leads to the fact that the dominant role in the regulation of heart rhythm begins to play neurohumoral factors (VLF-band). It was found that under conditions of premedication with H- or M-cholinolytics, when rats do not develop cardiac rhythm disturbances, the initial decrease in the severity of neurohumoral and subsequent increase in sympathetic and, to a lesser extent, parasympathetic influences is common. In this case, vagosympathetic balance is not decisive. In case the influence of neurohumoral factors increases after premedication, then later there is a decrease in the proportion of nerve influences and the occurrence of PHRBC. The obtained data suggest that in newborn rats both direct blockade of T-VDCC and changes in ICaT current mediated through M3-subtype muscarinic cholinoreceptors lead to disruption of pacing and development of PHRBC.

Spectral Analysis of Heart Rate Variability Based on the Hilbert-Huang Method.

Analysis of heart rate variability (HRV) is widely used for noninvasive assessment of the state of the regulation systems of the heart. The aim of this study was to evaluate the capabilities of the Hilbert-Huang method for calculating spectral parameters of HRV in comparison with the commonly used Fourier analysis. Fourier analysis allows estimation of averaged spectral amplitudes and power of HRV oscillations in fixed frequency intervals, which are associated with the activity of sympathetic, parasympathetic, and humoral regulation systems. Using the Hilbert-Huang method, we revealed four spectral components, described by Gaussian functions, in which HRV oscillations are concentrated, and showed the absence of fixed boundaries between them. The obtained energy quantitative characteristics of the spectral components of heart rhythm oscillations can serve as the basis for diagnostic methods of heart rhythm regulation, supplementing the commonly used ones.

Adynamic response to cold pain reflects dysautonomia in type 1 diabetes and polyneuropathy

Cardiac autonomic neuropathy (CAN), widely assessed by heart rate variability (HRV), is a common complication of long-term diabetes. We hypothesized that HRV dynamics during tonic cold pain in individuals with type 1 diabetes mellitus (T1DM) could potentially demask CAN. Forty-eight individuals with long-term T1DM and distal symmetrical polyneuropathy and 21 healthy controls were included. HRV measures were retrieved from 24-h electrocardiograms. Moreover, ultra-short-term HRV recordings were used to assess the dynamic response to the immersion of the hand into 2 °C cold water for 120 s. Compared to healthy, the T1DM group had expectedly lower 24-h HRV measures for most components (p < 0.01), indicating dysautonomia. In the T1DM group, exposure to cold pain caused diminished sympathetic (p < 0.001) and adynamic parasympathetic (p < 0.01) HRV responses. Furthermore, compared to healthy, cold pain exposure caused lower parasympathetic (RMSSD: 4% vs. 20%; p = 0.002) and sympathetic responses (LF: 11% vs. 73%; p = 0.044) in the T1MD group. QRISK3-scores are negatively correlated with HRV measures in 24-h and ultra-short-term recordings. In T1DM, an attenuated sympathovagal response was shown as convincingly adynamic parasympathetic responses and diminished sympathetic adaptability, causing chronometric heart rhythm and rigid neurocardiac regulation threatening homeostasis. The findings associate with an increased risk of cardiovascular disease, emphasizing clinical relevance.

Pathological Heart Rate Regulation in Apparently Healthy Individuals.

Cardiovascular diseases are the leading cause of morbidity and mortality in adults worldwide. There is one common pathophysiological aspect present in all cardiovascular diseases-dysfunctional heart rhythm regulation. Taking this aspect into consideration for cardiovascular risk predictions opens important research perspectives, allowing for the development of preventive treatment techniques. The aim of this study was to find out whether certain pathologically appearing signs in the heart rate variability (HRV) of an apparently healthy person, even with high HRV, can be defined as biomarkers for a disturbed cardiac regulation and whether this can be treated preventively by a drug-free method. This multi-phase study included 218 healthy subjects of either sex, who consecutively visited the physician at Gesundheit clinic because of arterial hypertension, depression, headache, psycho-emotional stress, extreme weakness, disturbed night sleep, heart palpitations, or chest pain. In study phase A, baseline measurement to identify individuals with cardiovascular risks was done. Therefore, standard HRV, as well as the new cardiorhythmogram (CRG) method, were applied to all subjects. The new CRG analysis used here is based on the recently introduced LF drops and HF counter-regulation. Regarding the mechanisms of why these appear in a steady-state cardiorhythmmogram, they represent non-linear event-based dynamical HRV biomarkers. The next phase of the study, phase B, tested whether the pathologically appearing signs identified via CRG in phase A could be clinically influenced by drug-free treatment. In order to validate the new CRG method, it was supported by non-linear HRV analysis in both phase A and in phase B. Out of 218 subjects, the pathologically appearing signs could be detected in 130 cases (60%), p < 0.01, by the new CRG method, and by the standard HRV analysis in 40 cases (18%), p < 0.05. Thus, the CRG method was able to detect 42% more cases with pathologically appearing cardiac regulation. In addition, the comparative CRG analysis before and after treatment showed that the pathologically appearing signs could be clinically influenced without the use of medication. After treatment, the risk group decreased eight-fold-from 130 people to 16 (p < 0.01). Therefore, progression of the detected pathological signs to structural cardiac pathology or arrhythmia could be prevented in most of the cases. However, in the remaining risk group of 16 apparently healthy subjects, 8 people died due to all-cause mortality. In contrast, no other subject in this study has died so far. The non-linear parameter which is able to quantify the changes in CRGs before versus after treatment is FWRENYI4 (symbolic dynamic feature); it decreased from 2.85 to 2.53 (p < 0.001). In summary, signs of pathological cardiac regulation can be identified by the CRG analysis of apparently healthy subjects in the early stages of development of cardiac pathology. Thus, our method offers a sensitive biomarker for cardiovascular risks. The latter can be influenced by non-drug treatments (acupuncture) to stop the progression into structural cardiac pathologies or arrhythmias in most but not all of the patients. Therefore, this could be a real and easy-to-use supplemental method, contributing to primary prevention in cardiology.