National Repository of Grey Literature 8 records found  Search took 0.01 seconds. 
HRV analysis in the context of daily activities
Indrák, Václav ; Smital, Lukáš (referee) ; Novotná, Petra (advisor)
The aim of this bachelors thesis is to measure ECG recordings on voulenteers, and following analysis of HRV from these recordings. It persues the explanation of basic metrics used to evaluate HRV, used both in clinical and scientific practice and their following programming implementation in Matlab environment to achieve the most accurate results possible, which are than assessed.
The verification of usability of the heart rate variability in the training process for cyclists
KADLEC, Jakub
Alternation of intensity and rest in the right proportion is crucial for the development of sports performance. The correct timing of the practice can be simplified by monitoring heart rate variability. The aim of the thesis is to verify connection between the current readiness to give a sport performance and HRV. The verification had been performed using HRV monitoring and stress tests. The stress tests were undertaken in Functional Load Diagnostic Laboratory belonging to the Department of Sport Studies at the University of South Bohemia. The experiment had been running for two months. The participants of the experiment were two cyclists of XC category. One of the limiting factors of the experiment is the number of participants. The statistical significance of values was gained by comparing spirometry and spectral analysis of heart rate variability results. Correlation of values of sympathetic nervous system stimulation and minute ventilation can be considered as statistically important. Connections of only one of two experiment participants were statistically important for the thesis. The first of the probands showed 32 statistically important correlations out of 140. The second of the probands showed 11 statistically important correlations out of 140. More statistically significant correlations have been proven in cyclist with higher level of performance. The connection between the level of performance and the HRV, the importance of which is particularly in determining the level of compensation, has been confirmed at least to some extent.
Neuromodulation in heart failure
Naar, Jan ; Ošťádal, Petr (advisor) ; Rokyta, Richard (referee) ; Vízek, Martin (referee)
The prognosis of heart failure with reduced ejection fraction remains poor. Neurohumoral activation, including increased cardiac sympathetic nerve activity, plays an important role in the pathogenesis as well as disease progression. Recently, several neuromodulation strategies have been proposed that aim to directly affect the residual autonomic imbalance. Spinal cord stimulation is one of the proposed methods. In the clinical part of this project, we assessed the mid-term effect of spinal cord stimulation on cardiac sympathetic nerve activity and the acute effect on autonomic balance. In the total study population, we did not detect any changes in cardiac sympathetic nerve activity or heart rate variability. However, we observed that the patients with high baseline sympathetic nerve activity or low heart rate variability responded favourably to therapy, reflected in reduced cardiac sympathetic nerve activity and increased heart rate variability. Considering these results, we conducted an experimental study focused on the effect of acute severe heart failure on heart rate variability. In a porcine model of hypoxic myocardial dysfunction, we observed a significant reduction in heart rate variability in all parameters recorded. Our results indicate that spinal cord stimulation may improve autonomic...
HRV analysis in the context of daily activities
Indrák, Václav ; Smital, Lukáš (referee) ; Novotná, Petra (advisor)
The aim of this bachelors thesis is to measure ECG recordings on voulenteers, and following analysis of HRV from these recordings. It persues the explanation of basic metrics used to evaluate HRV, used both in clinical and scientific practice and their following programming implementation in Matlab environment to achieve the most accurate results possible, which are than assessed.
Contribution of particular vasoactive systems in the development of chronic kidney disease
Drábková, Natálie ; Vaněčková, Ivana (advisor) ; Vaňourková, Zdeňka (referee)
Chronic kidney disease (CKD) is a life-threating disease which arises as a frequent consequence of diabetes and hypertension. Since it is going on silently, CKD often progresses to the end-stage renal disease. It is therefore necessary to combat this disease especially due to the fact that the world population is growing old. The aim of this work was to determine the contribution of selected vasoactive systems contributing to the maintenance of high blood pressure in the developmental and established phase of CKD. Two models of CKD were used: 5/6 nephrectomy in Ren-2 transgenic rats (TGR) and stenosis of renal artery (2K1C) in Wistar rats. We demonstrated that renin-angiotensin system does not play so important role in blood pressure maintenance in both CKD models. By contrast, a more important role has sympathetic nervous system. During both the developmental and established phase of CKD, vasoconstrictor systems prevail above vasodilator NO-synthase effects. In fact, the role of NO-dependent vasodilation gradually decreased in nephrectomized TGR rats, while it was unchanged in Wistar rats with 2K1C hypertension.
Contribution of particular vasoactive systems in the development of chronic kidney disease
Drábková, Natálie ; Vaněčková, Ivana (advisor) ; Vaňourková, Zdeňka (referee)
Chronic kidney disease (CKD) is a life-threating disease which arises as a frequent consequence of diabetes and hypertension. Since it is going on silently, CKD often progresses to the end-stage renal disease. It is therefore necessary to combat this disease especially due to the fact that the world population is growing old. The aim of this work was to determine the contribution of selected vasoactive systems contributing to the maintenance of high blood pressure in the developmental and established phase of CKD. Two models of CKD were used: 5/6 nephrectomy in Ren-2 transgenic rats (TGR) and stenosis of renal artery (2K1C) in Wistar rats. We demonstrated that renin-angiotensin system does not play so important role in blood pressure maintenance in both CKD models. By contrast, a more important role has sympathetic nervous system. During both the developmental and established phase of CKD, vasoconstrictor systems prevail above vasodilator NO-synthase effects. In fact, the role of NO-dependent vasodilation gradually decreased in nephrectomized TGR rats, while it was unchanged in Wistar rats with 2K1C hypertension.
The role of Rho-kinase signaling pathway in the regulation of blood pressure
Brunová, Aneta ; Zicha, Josef (advisor) ; Kopkan, Libor (referee)
Calcium sensitization represents a mechanism that enables vascular smooth muscle cells to change the sensitivity of the contractile apparatus to intracellular calcium The aim of this study was to determine to what extent is calcium sensitization modulated by the renin- angiotensin system (RAS), sympathetic nervous system (SNS), nitric oxide (NO) and prostanoids produced by cyclooxygenase (COX). For this purpose we studied the effects of acute and chronic blockade of particular systems on blood pressure changes elicited in conscious normotensive rats by administration of Rho-kinase inhibitor fasudil. Adult male chronically cannulated Wistar rats were used in all experiments. Main findings of this study are as follow: 1) Decrease of blood pressure elicited by Rho-kinase inhibition was enhanced under the conditions of acute NOS inhibition. Inhibition of NOS was shown to have a bigger effect than COX inhibition (this was confirmed under the conditions of acute RAS and SNS inhibition as well). These findings are in agreement with the hypothesis that NO exerts a suppressive effect on calcium sensitization. 2) Chronic NOS inhibition caused hypertension characterized by a more pronounced blood pressure lowering after Rho-kinase inhibition in comparison with control. NO chronically suppresses the calcium...
L-serine induced effects on blood pressure in normotensive and hypertensive rats: the influence of anesthesia
Bencze, Michal ; Zicha, Josef (advisor) ; Husková, Zuzana (referee)
Anesthetics cause profound alterations in respiratory and cardiovascular systems. Our experiments demonstrated that different anesthetics caused different changes in blood pressure regulating components. The role of particular BP regulating systems was disclosed by their selective inhibition - sympathetic nervous system blocked by pentolinium (peripheral ganglionic blockade), renin-angiotensin system by captopril (angiotensin converting enzyme blocker) and nitric oxide production by L-NAME (nitric oxide synthase blocker). Components of blood pressure regulating mechanisms in conscious normotensive Wistar rats and spontaneously hypertensive rats were compared with four different groups of anesthetized rats by pentobarbital, ketamine-xylazine, chloralose-urethane and isoflurane. Each anesthesia caused different hemodynamic changes. If hemodynamic conditions should be similar to conscious rats, the most suitable anesthetic is pentobarbital. L-serine-induced effects represent endothelium-derived hyperpolarizing factor (EDHF)-mediated response, which is a type of endothelium-dependent regulation of vascular tone, independent of nitric oxide and prostacyclin production. Pronounced L-serine effects on blood pressure were shown in NO-deficient type of hypertension. Our study demonstrated its pronounced effects in...

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