Increase in cardioprotective SUR2A does not alter heart rate and heart rate regulation by physical activity and diurnal rhythm

SUR2A is an ABC protein serving as a regulatory subunit of ATP-sensitive (KATP) channels. An increase in SUR2A levels is cardioprotective and it is a potential therapeutic strategy against ischaemic heart disease, heart failure and other diseases. However, whether overexpression of this protein has any adverse effects is yet to be fully understood. Objectives Here, we examined the heart rate and the heart rate diurnal variation in mice overexpressing SUR2A (SUR2A+) and their littermate controls (WT) using ECG telemetry that was continuously recorded for 14 days (days 8–23 post-radiotransmitter implantation). Methods Using SigmaPlot 14.0 and Microsoft Excel, Area Under the Curve (AUC) for each parameter was calculated and plotted in a graph. Results Both WT and SUR2A+ mice were more physically active during nights and there were no significant differences between two phenotypes. Physical activity was associated with increased heart rate in both phenotypes, but there were no differences in heart rate between phenotypes irrespective of physical activity or time of the day. A diurnal heart rate variation was preserved in the SUR2A+ mice. As area under the curve (AUC) analysis has the potential to reveal differences that are invisible with other statistical methods, we compared AUC of heart rate in SUR2A+ and WT mice. This analysis did not yield anything different from traditional analysis. Conclusions We conclude that increased SUR2A levels are not associated with changes in physical activity, heart rate and/or circadian rhythm influence on the heart rate. This lack of adverse effects supports a notion that manipulation with SUR2A levels is a promising cardioprotective strategy.

Comparative Characteristics of Sensorimotor Reactions of Highly Qualified Athletes with Different Types of Heart Rate Regulation

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

Features of heart rate variability in patients with takotsubo syndrome

Funding Acknowledgements Type of funding sources: None. Main funding source(s): North-Western State Medical University named after I.I. Mechnikov Objective to study the features of autonomic regulation of sinus rhythm features of autonomic regulation of cardiac sinus rhythm in patients with Takotsubo syndrome (TTS) during inpatient stay in hospital. Materials and methods. The study included 25 female patients (the median age 57.5 ± 28.5 years) with TTS, diagnosis was based on the InterTAK criteria. On the 5-7th day after admission, the heart rate variability (HRV) was assessed both at rest and cardiac autonomic function tests: the deep breathing test (DBT) and active orthostatic test (AOT) with the usage of a computer diagnostic system «Valenta». RESULTS According to HRV data, initially at rest, the majority of the studied patients predominantly had a parasympathetic impact on the heart rate regulation: in 70% - increased parasympathetic influence, in 17% - increased sympathetic influence, in 13% - a balanced heart rate regulation. When performing a DBT, the predominance of the parasympathetic influence on the heart rate was noted both in spectral parameters and according to the data of time analysis (HF during DBT increased 1.8 times up to 489.6 ± 114.2 ms2 (p <0.05) ; LF decreased 1.7 times up to 254.1 ± 70.3 ms2 (p <0.05); VLF increased 2.8 times up to 402.3 ± 101.8 ms2 (p <0, 05); TP increased 1.4 times up to 1145.9 ± 251.3 ms2; CV increased 1.3 times up to 6.5 ± 0.7% (p <0.05); SDNN increased 1.3 times up to - 58.7 ± 6.6 ms (p <0.05). HRV measured during an AOT showed a paradoxical evaluation in the parasympathetic impact on the heart rate (HF increased by 1.8 times and reached - 488.0 ± 104.7 ms2 (p <0.05); LF decreased by 1.1 times up to 408 , 4 ± 103.6 ms2; VLF increased 1.2 times up to 166.4 ± 52.2 ms2; TP increased 1.3 times up to 1062.8 ± 181.1 ms2 (p <0.05); CV increased 1.6 times up to 8.0 ± 0.9% (p <0.05); SDNN increased 1.4 times up to 62.6 ± 7.5 ms (p <0.05)). Conclusions During the index hospital inpatient stays the majority of patients with TTS have a vegetative imbalance due to increased parasympathetic influence on the heart rate, both at rest and during a deep breathing test and an active orthostatic test. This fact is quite unexpected and requires further study.

Physiological Balance of the Body: Theory, Algorithms, and Results

Aim: To confirm algorithm of determination of risk groups with physiological imbalance in the population exposed to unfavorable anthropogenic influences. Methods: The testing included such functional systems as constitution, myocardial contractility, autonomic regulation of the heart rate, regulation of peripheral circulation, psychomotor regulation, respiratory regulation and metabolism. Monitoring is carried out using computerized measurement instrumentation and data processing systems. Results: A risk group with pronounced shifts in the physiological balance was identified, which made up 38% of the surveyed population. The greatest contribution to the imbalance was made by the psychomotor system. Conclusion: We analyzed two different components of organism’s adaptation: resistance and resilience. Physiological systems experiencing increasing load attain a tipping points, where even a weak disturbing influence can induce transition to a qualitatively different state. This transition can result in either recovery of the regulatory stability of the system, or its transition to a lower level (dysregulation) with further development of a pathology. In this regard, of paramount importance is early detection of the signals about approaching the tipping points, one of these is the slowing down phenomenon during functional tests. In view of intricate interaction of physiological systems, recording of as much indicators as possible is advisable. The method of partial correlations is effective for evaluation of adaptive interaction of systems.

Нeart rate variability of children aged 8-11 with deprivation of auditory function

ntroduction.Currently, there are quite a number of publications on the peculiarities of heart rate in children with hearing impairments. However, such studies were conducted with individuals who had varying degrees of deafness and virtually did not examine children with congenital deafness.Children with congenital deafness are likely to have significant changes in cardiovascular system (CVS) indicators compared to their healthy peers. Purpose.The aim of the study was to elucidate the mechanisms of heart rate regulation in children with deprivation of auditory function during active orthostatic testing. Methods. The study involved 15 children: boys (7 individuals) and girls (8 individuals) aged 8-11 with congenital deafness and 17 almost healthy peers. Cardiorhythmograms were recorded with spectral characteristics of heart rate: (VLFms2, less than 0.05 Hz), low (LFms2, 0.05--0.4 Hz) frequencies; the ratio of LF/HF was considered.Results.The results of the study suggest that a group of childrenwith hearing deprivation in all indicators of spectral analysis of HRV had a much lower reactivity of the CVScompared to their healthy peers. The LF indicator did not change significantly, and therefore the sympathetic link of regulation did not play a significant role. However, the contribution of the parasympathetic system, which can be judged by HF, was significantly reduced in both groups. Thus, we can assume that the regulation of blood circulation was due to reduced activation of the parasympatheticlink with constant sympathetic. This feature is indicated by the indicator of vagosympathetic balance of the LF / HF ratio. Its changes reached quite significant values: 87.5% in deaf and 262.5% in healthy children. This indicates the leading role of the sympathetic system in the regulation of heart rhythm in children 8-11 years during orthostasis. However, the differences in the reactivity of the CVSof representatives of different groups indicated a less pronounced degree of activation of this link in the regulation of children with derivation of auditory function.The ratio of the length and width of the autocorrelation cloud (L / W) indicated a similar dependence. The dynamics of this indicator in the direction of increase may indicate a change in the intensity of the autonomic circuit regulation of cardiac activity. 202159In healthy subjects, these changes occurred with a greater degree of activation of central regulatory mechanisms than in children with hearing impairments.Because TP is an almost complete physiological analogue of SDNN, its decrease during orthostasis in children with hearing deprivation by 20.1% and 44.2% in healthy people indicates that the total effect of central regulation mechanisms decreases.Originality.Currently, there are virtuallyno data on reactive changes in the cardiovascular system of children with hearing impairments to postural gravitational loads, especially in relation to children with congenital deafness. This is important given that information about the reactions of thecardiovascular system of children with hearing impairments will allow you to adjust the exercise, choose the optimal motor mode and predict possible deviations or pathologies.Conclusion.Children with the deprivation of auditory function are characterized by more pronounced maladaptive responses of the cardiovascular system to orthostatic load than their healthypeers. Central regulatory mechanisms in deaf children have less pronounced activation compared to healthy children. At orthostatic test, in both groups of subjects, regulation of blood circulation is carried out mainly at the expense of a parasympathetic link of an autonomic nervous system.Keywords. deprivation of auditory function, heart rate variability, spectral analysis

Applying of speleoclimatotherapy for improving children’s health and adaptational possibilities

The article presents the results of the use of speleoclimatotherapy in recreational activities in children of primary school age. In the course of the study, we analyzed indicators of heart rate variability in children depending on the initial vegetative status. In vagotonics and normotonics, there was an increase in the activity of the sympathetic division of the autonomic nervous system, and in sympatotonics, there was a decrease in HRV parameters within the age norm, characteristic of increased activity of the sympathetic division of the autonomic nervous system. Such changes can occur when the adaptive reserves of the childs body increase. However, when using speleoclimatotherapy during recreational activities, it is necessary to take into account the initial level of vegetative activity of heart rate regulation in children.