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New Approaches in Cardiac Optical Mapping
Švrček, Martin ; Kizek, René (referee) ; Sovka, Pavel (referee) ; Provazník, Ivo (advisor)
This dissertation deals with new approaches in cardiac optical mapping. The principle of cardiac optical mapping as well as the current research in this field was described. The new measurement system was developed and its characteristics presented. The system design allows epicardial and endocardial mapping, employing new ratiometric techniques in 2D acquisition and simultaneous electrical and optical mapping. The measured characteristics of fluorescent dye di-4-ANEPPSS were presented. The relation between movement and consequent motion artifacts is well described. Several new approaches in signal processing were proposed, including new ratiometry technique and using image registration to suppress motion artifacts. The algorithm for elastic image registration of optical signals and innovative method for verification of registration process were presented. Application of all proposed approaches and its results are included and discussed.
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Effect of surface electrode type on quality of decopmposition of surface EMG signal
Strusková, Edita ; Otáhal, Jakub (advisor) ; Michalec, Radim (referee)
Title: Effect of surface electrode type on quality of decomposition of surface EMG signal Objectives: The aim of this thesis is to evaluate the effect of surface electrode type, which was used for EMG record, on the quality of decomposition of surface EMG signal using decomposition software EMGlab. Methods: The form of the thesis is an experimental essay. It was detected an EMG signal from one healthy volunteer during mild cyclic contraction. It was used three different types of electrodes (standard surface electrode, tetrode, tetrode with saw-off spikes) for EMG signal detection. These signals were decomposed in program EMGlab. The results were processed in program MS Excel, compared with each other and graphically displayed. Results: The measurement verified a hypothesis which claimed that the used type of electrode affects the quality of automatic decomposition. The best results of automatic decomposition provide the signal gained from the standard surface electrode. Key words: action potential, decomposition, surface electrodes, EMG signal, tetrode, electromyography
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3D Model of Cardial Tissue Electrical Propagation
Míková, Monika ; Mézl, Martin (referee) ; Hejč, Jakub (advisor)
The aim of this master thesis is to create a simple 3D electro-anatomical model of cardiac tissue that will be able to simulate the electrical activation in both a healthy heart and a heart with arrhytmogenic substrate. The model of electrical activation is realized in the COMSOL Multiphysics, simulation software for modelling using the finite element method. The Fitzhugh-Nagumo equation was used to model the excitatory feature of the myocardium and 2D models of myocardial tissue describing the propagation of action potential in healthy tissue, ischemic tissue, spontaneous action potential formation in the SA node, and spiral wave formation were first developed based on appropriate parameters. Subsequently, simplified 3D models of the heart describing the spread of excitement in a healthy heart, in the presence of accessory pathway and in third-degree atrioventricular block were created. The simplified 3D heart model offers a compromise between computational load and model complexity and can be used as a diagnostic tool for tissue and whole heart adjustment with appropriate equation parameter settings.
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Fuzzy Neural Networks for Pattern Classification
Ollé, Tamás ; Kontár, Stanislav (referee) ; Vágnerová, Jitka (advisor)
Práce popisuje základy principu funkčnosti neuronů a vytvoření umělých neuronových sítí. Je zde důkladně popsána struktura a funkce neuronů a ukázán nejpoužívanější algoritmus pro učení neuronů. Základy fuzzy logiky, včetně jejich výhod a nevýhod, jsou rovněž prezentovány. Detailněji je popsán algoritmus zpětného šíření chyb a adaptivní neuro-fuzzy inferenční systém. Tyto techniky poskytují efektivní způsoby učení neuronových sítí.
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Electrogram processing and analysis
Hanák, Pavel ; Kolářová, Jana (referee) ; Janoušek, Oto (advisor)
The aim of the study was focused on problem of electrograms recording from alive tissue. Study of electrograms recording was extended with noise analysis and its elimination. Elimination of noise and disturption was made in program Matlab; lowpass filtration and wavelet transformation was used. Application for electrograms analysis was developed in latter part of this work.
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The influence of stochastic behaviour of ion channels on the signal and information transfer at excitable neuronal membranes
Šejnová, Gabriela ; Kuriščák, Eduard (advisor) ; Maršálek, Petr (referee)
The stochastic behavior of voltage-gated ion channels causes fluctuations of conductances and voltages across neuronal membranes, contributing to the neuronal noise which is ubiquitous in the nervous system. While this phenomenon can be observed also on other parts of the neuron, here we concentrated on the axon and the way the channel noise influences axonal input-output characteristics. This was analysed by working with our newly created computational compartmental model, programmed in Matlab environment, built up using the Hodgkin-Huxley mathematical formalism and channel noise implemented via extended Markov Chain Monte Carlo method. The model was thoroughly verified to simulate plausibly a mammalian axon of CA3 neuron. Based on our simulations, we confirmed quantitatively the findings that the channel noise is the most prominent on membranes with smaller number of Na+ and K+ channels and that it majorly increases the variability of travel times of action potentials (APs) along axons, decreasing thereby the temporal precision of APs. The simulations analysing the effect of axonal demyelination and axonal diameter correlated well with other finding referred in Literature. We further focused on spike pattern and how is its propagation influenced by inter-spike intervals (ISI). We found, that APs fired...
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Effect of surface electrode type on quality of decopmposition of surface EMG signal
Strusková, Edita ; Otáhal, Jakub (advisor) ; Michalec, Radim (referee)
Title: Effect of surface electrode type on quality of decomposition of surface EMG signal Objectives: The aim of this thesis is to evaluate the effect of surface electrode type, which was used for EMG record, on the quality of decomposition of surface EMG signal using decomposition software EMGlab. Methods: The form of the thesis is an experimental essay. It was detected an EMG signal from one healthy volunteer during mild cyclic contraction. It was used three different types of electrodes (standard surface electrode, tetrode, tetrode with saw-off spikes) for EMG signal detection. These signals were decomposed in program EMGlab. The results were processed in program MS Excel, compared with each other and graphically displayed. Results: The measurement verified a hypothesis which claimed that the used type of electrode affects the quality of automatic decomposition. The best results of automatic decomposition provide the signal gained from the standard surface electrode. Key words: action potential, decomposition, surface electrodes, EMG signal, tetrode, electromyography
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Optical Measurement of Electromechanical Characteristics of Heart Cells
Čmiel, Vratislav ; Križanová,, Olga (referee) ; Babula, Petr (referee) ; Provazník, Ivo (advisor)
Dissertation is focused on the application of optical measurement methods using techniques of optical microscopy and fluorescence microscopy in measurements of electromechanical characteristics of isolated cardiac cells and clusters of differentiated cardiomyocytes. The first proposed method uses a practical combination of fluorescence microscopy equipped with fluorescent fast and high-resolution camera and atomic force microscopy for simultaneous measurement of calcium transients and contraction of cardiomyocyte clusters. The signals obtained undergoes filtration, processing and analysis. Result function parameters obtained by analyzing signals after application of caffeine are evaluated by comparison with functional parameters obtained during the control measurement. The second proposed method is applied to the cardiomyocyte clusters for the purpose of cardiomyocyte contraction signals measurement. The signals obtained by optical methods are analyzed and compared with the reference signal obtained using atomic force microscopy. Optical measurement method of cell contractins based on detection of cell ends using adjusting of microscopy images by re-sharpening and fluorescence method for cardiomyocyte contractions measurements were designed to increase realiability in simultaneous measurement of cell contractions simultaneously with calcium transients in isolated cardiomyocytes experiments.
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Software for ECG analysis
Plch, Vít ; Hejč, Jakub (referee) ; Ronzhina, Marina (advisor)
This bachelor thesis deals with design and construction of tool for analysing electrocardiograms. The theoretical part deals with the origin of the action potential, propagation of the action potential through conduction system of the heart, failure of electrical impulse propagation through the con-duction system; different aspects of disorders, which can be found in experimental electrograms recorded from animal isolated hearts (database of electrograms, the Department of Biomedical En-gineering, FEEC, BUT), are also discussed. Software for electrograms draw and annotation available on the DBME, namely EG_Anotation and EG_RR_View, are described. As a result, the design and construct of ECG_ANN, the tool for the electrograms annotation, is proposed with regard to the advantages and disadvantages of mentioned software. At the end of the bachelor thesis there are the guide for ECG_ANN and discussion about problems which appears in design and construct of this tool.
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