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Analysis of High-Frequency ECG and Mechano-Electric Coupling in Isolated Heart
Novotná, Petra ; Ronzhina, Marina (oponent) ; Hejč, Jakub (vedoucí práce)
This master's thesis deals with the analysis of high frequency ECG from the perspective of mechano-electric coupling in isolated rabbit heart. The first part of this thesis is the literature review considering given thematics. It contains information about formation and genesis of ECG and action potential at the chemical and electric level, mechano-electric coupling. The thesis contains the chapter about signal averaging as the technique for gaining the signal-to-noise ratio when analysing HF ECG. In the part of practical application is the knowledge applied to the long recordings of isolated rabbit heart's ECG. There is the description of perfusion system according to Neely included. The realisation consists of data from 15 isolated rabbit hearts to be analysed and explored for the presence of system's reaction to the change of input parameters (preload, afterload) for the case of pressure-volume data. The results have been connected to the similar ones from HF ECG and altogether they create the description of mechano-electric coupling of heart. The reuslts have been statistically tested and evaluated.
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Study of Electrophysiological Function of the Heart in Experimental Cardiology
Ronzhina, Marina ; Tyšler, Milan (oponent) ; Halámek, Josef (oponent) ; Kolářová, Jana (vedoucí práce)
Isolated heart is widely used in experimental cardiology to study myocardial ischemia and infarct, left ventricular hypertrophy, myocarditis, etc. Nevertheless, the standardized criteria for assessment of above disorders in animal models are missing that complicates interpretation of the results obtained in such studies. It is of special importance, if several pathologies are presented simultaneously, when possible co-effects cannot be simply identified and analysed. Besides the condition of the heart, there are many other factors playing important role in data acquisition and analysis. In this work, electrophysiological effects of increased left ventricular mass (intrinsic factor) and voltage-sensitive dye di-4-ANEPPS (external factor) are evaluated on rabbit isolated hearts under non-ischemic and ischemic condition. Although both phenomena are quite frequent in animal studies, their effects on ischemia manifestations and electrogram-based ischemia detection accuracy have not been quantitatively described yet. Results of quantification of ischemia-induced changes in heart function (under normal conditions, increased LV or dye administration) by analysis of various EG and VCG parameters are summarized. Such important aspects as recording electrodes placement, method of parameters calculation (using or without outcomes of manual EG delineation) and definition of the beginning of ‘true’ ischemic injury in preparation (methodological factors) are also addressed. Along with it, different tools for automatic detection of ischemia in data are presented. According to the results of statistical analysis of parameters and testing the detectors on different data, all above mentioned phenomena (both heart-related and methodological) should be taken into account to ensure successful study of the heart electrical activity.
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Analysis of High-Frequency ECG and Mechano-Electric Coupling in Isolated Heart
Novotná, Petra ; Ronzhina, Marina (oponent) ; Hejč, Jakub (vedoucí práce)
This master's thesis deals with the analysis of high frequency ECG from the perspective of mechano-electric coupling in isolated rabbit heart. The first part of this thesis is the literature review considering given thematics. It contains information about formation and genesis of ECG and action potential at the chemical and electric level, mechano-electric coupling. The thesis contains the chapter about signal averaging as the technique for gaining the signal-to-noise ratio when analysing HF ECG. In the part of practical application is the knowledge applied to the long recordings of isolated rabbit heart's ECG. There is the description of perfusion system according to Neely included. The realisation consists of data from 15 isolated rabbit hearts to be analysed and explored for the presence of system's reaction to the change of input parameters (preload, afterload) for the case of pressure-volume data. The results have been connected to the similar ones from HF ECG and altogether they create the description of mechano-electric coupling of heart. The reuslts have been statistically tested and evaluated.
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Study of Electrophysiological Function of the Heart in Experimental Cardiology
Ronzhina, Marina ; Tyšler, Milan (oponent) ; Halámek, Josef (oponent) ; Kolářová, Jana (vedoucí práce)
Isolated heart is widely used in experimental cardiology to study myocardial ischemia and infarct, left ventricular hypertrophy, myocarditis, etc. Nevertheless, the standardized criteria for assessment of above disorders in animal models are missing that complicates interpretation of the results obtained in such studies. It is of special importance, if several pathologies are presented simultaneously, when possible co-effects cannot be simply identified and analysed. Besides the condition of the heart, there are many other factors playing important role in data acquisition and analysis. In this work, electrophysiological effects of increased left ventricular mass (intrinsic factor) and voltage-sensitive dye di-4-ANEPPS (external factor) are evaluated on rabbit isolated hearts under non-ischemic and ischemic condition. Although both phenomena are quite frequent in animal studies, their effects on ischemia manifestations and electrogram-based ischemia detection accuracy have not been quantitatively described yet. Results of quantification of ischemia-induced changes in heart function (under normal conditions, increased LV or dye administration) by analysis of various EG and VCG parameters are summarized. Such important aspects as recording electrodes placement, method of parameters calculation (using or without outcomes of manual EG delineation) and definition of the beginning of ‘true’ ischemic injury in preparation (methodological factors) are also addressed. Along with it, different tools for automatic detection of ischemia in data are presented. According to the results of statistical analysis of parameters and testing the detectors on different data, all above mentioned phenomena (both heart-related and methodological) should be taken into account to ensure successful study of the heart electrical activity.
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