National Repository of Grey Literature 53 records found  beginprevious44 - 53  jump to record: Search took 0.01 seconds. 
Heart rate variability in decreasing of alertness level
Strublová, Tereza ; Provazník, Ivo (referee) ; Janoušek, Oto (advisor)
Objective of this study is to familiarize with problems of measuring heart rate variability. At first there is described physiology of vascular system, then practical measuring of heart rate variability during falling asleep. At the end of this project is the statistical processing of results and comparison of the differences between heart rate variability during sleep and wakefulness.
Analysis of Heart Rate Variability
Peterek, Jan ; Janoušek, Oto (referee) ; Kozumplík, Jiří (advisor)
The goal of this thesis is to describe and implement the chosen method for estimating the power spectrum of heart rate variability. Two methods have been developed that are aligned with each other conclusion. This thesis of theoretical and practical parts. The theoretical part describes the theory of the ECG signal and heart rate variability in the practical part the realization of the two selected methods for estimating the power spectrum of heart rate variability, and several other auxiliary display in Matlab
LabView and biosignal analysis
Kutílek, Miloš ; Harabiš, Vratislav (referee) ; Kolář, Radim (advisor)
This bachelor’s thesis deals with the analysis of biological signals in LabView environment. Mainly it focuses on the analysis of ECG signals. The thesis also describes the theory of electrocardiogram and occupies by several programs which consider various approaches to digital filtering of ECG signals, programs for detection R wave by different ways and simple cardiology monitor.
Analysis of long-term electrocardiograms
Vojtíšek, Jiří ; Vítek, Martin (referee) ; Kolářová, Jana (advisor)
This work deals with long-therm analysis of electrocardiogram using heart rate variability representation. Project explains heart anatomy and electrophysiology, creation and shape of ECG curve. Heart rate variability is described by power spectral density, which we obtain from created algorithm. This algorithm was used in graphic user interface application Spider Pig Analysis, which analyze long-term ECG focused on showing Power Spectral Density graph. Practicality of this program was verified in experiment. In the experiment HRV at rest and HRV at tilt were compared.
Influence of autonomic nervous system in the inducibility of atrial fibrillation.
Šrutová, Martina ; Provazník, Ivo (referee) ; Kolářová, Jana (advisor)
Cílem této práce je zjištění změn předcházejícím fibrilaci síní. Pozorována je rovnováha mezi sympatikem a parasympatikem. Do experimentu výzkumného ústavu Cleavlendské kliniky bylo zapojeno šest psů různých ras. Signály EKG byly získány Holterovským 24hodinovým monitorováním. Pomocí 40 vysokofrekvenčních impulsů (TI) byla každých 30 minut vyvolávána AF. Z 24hodinového signálu byly extrahovány kratší epizody. Každá z těchto epizod obsahovala 10 minut předcházejících TI a 3 minuty následující po TI. Desetiminutové epizody byly zpracovány automaticky, byly detekovány QRS komplexy a RR intervaly a vypočteny HRV parametry. Přítomnost a délka trvání AF byly zjištěny manuálně z tříminutových intervalů následujících po TI. Byla-li vyvolána AF o délce trvání kratší než 30 sekund došlo ve srovnání s epizodami bez výskytu AF k významným změnám tří HRV parametrů. HF parametr poklesl pro epizody s výskytem AF. LF parametr byl naopak vyšší v epizodách s AF. Pro AF delší než 30 sekund nebyly významné změny pozorovány. Změny v epizodách s krátkou AF mohly být způsobeny změnami vlivu sympatiku a parasympatiku. Ke vzniku dlouhých AF je pravděpodobně zapotřebí i jiného vlivu, který nemusí nutně souviset s nervovým systémem. K dalším analýzám je zapotřebí většího množství signálů.
Use of HRV analysis for automatic detection of ischemia in animal isolated heart
Vykoupil, Pavel ; Vítek, Martin (referee) ; Ronzhina, Marina (advisor)
This paper deals with HRV analysis, creating segments for this analysis, calculating HRV parameters and their classification for automatic detection of ischemia. First part of the work is dedicated to theoretical describtion of heart anatomy, ECG reading, its processing and methods of HRV analysis. Next part of this work outline the principle of creating segments used for calculation of HRV parameters. Last part of the work indtroduces classification of said parameters with the help of multilayered neural networks and finding their best possible setup based on least classification error and computing time achieved. Calculation of HRV parameters and classification was realized using software Matlab.
ECG classification using methods of HRV analysis
Caha, Martin ; Vítek, Martin (referee) ; Ronzhina, Marina (advisor)
This paper deals with the classification of ECG measured from isolated rabbit hearts during the experiment with repeated ischemia. Classification features were calculated using the methods of heart rate variability analysis. The results were statistically evaluated. Heart rate variability parameters were calculated using Kubios HRV, other calculations were performed in MATLAB. Artificial neural network was created to classify the analyzed parameters to specific groups.
Detrended fluctuation analysis for heart rate variability analysis
Šikner, Tomáš ; Ronzhina, Marina (referee) ; Janoušek, Oto (advisor)
Heart rate variability analysis can be used for a diagnosis of the cardiac diseases. The HRV analysis methods are divided into linear and nonlinear methods. Time-domain method is one of the simplest method and belongs to linear methods. Detrended fluctuation analysis DFA is nonlinear method made relatively recently. In this paper, it has been done the comparison of these two methods based on the changes detection in HRV caused by an ischemia.
Software for manual delineation of ECG signals
Jež, Radek ; Kozumplík, Jiří (referee) ; Vítek, Martin (advisor)
This thesis deals with evaluation EKG in terms of classification rhythm and analysis HRV. In theoretic part of work are described basics of heart physiology and its usual pathology, basics of electrocardiography, evaluation EKG and standard methods of HRV evaluation. In practical part are described algorithms used in created application. Mainly describes technique of rhythm evaluation, ectopic rhythms and delineation error elimination, data preparing for HRV evaluation, drift removal from DES and HRV evaluation methods. Created program was tested on CSE and MIT- BIH database records. For lack of suitable data and absence of tested data, it wasn’t possible to test all the classification rules of used algorithms. Tested part of program appears reliable and functional.
Analysis of Heart Rate Variability
Škrtel, Karol ; Kolářová, Jana (referee) ; Provazník, Ivo (advisor)
The project describes the methods useful for observe changes of heart rate in ECG signal. Heart rate variability become (HRV) the conventionally accepted term to describe variations of NN intervals between consecutive heart beats and generally it is function of instantaneous heart rate or NN interval on time. HRV may be evaluated by time domain or frequency domain measures. In Matlab was developed algorithm, realized like function, which counts HRV parameters from ECG signal series. Analysis in time domain adverts to high correlation between statistic and geometric parameters and similarly with signal HRV. Results of frequency domain analysis shows similarity of power spectral density, which was calculated by two different ways (from interpolated and no interpolated signal HRV). Functionality of developed algorithm was verified on each signal. Project results have signification in progress of analysis ECG signal methods with a view to observe pathological changes in heart rate.

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