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QRS complex detection in long electrograms
Novotná, Petra ; Hejč, Jakub (referee) ; Kozumplík, Jiří (advisor)
This bachelor thesis deals with the detection of the QRS complexes in long electrograms which were acquired by scanning isolated rabbit hearts. The first section of this thesis contains information about general detection principles. Some of those principles are de- scribed into details in the fourth chapter. The practical part consists of: the introduction of processed data, the description of specific algorithms used while solving the task and the realisation of those algorithms in the language of technical computing (MATLAB).
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QRS complex detection in electrograms
Mahdalová, Kateřina ; Chrobák, Martin (referee) ; Kozumplík, Jiří (advisor)
This work deals with QRS complex detection in isolated rabbit´s heart. In first part of the work is a description of human electrogram and summary of selected methods of QRS detection. In the practical part detectors which were implemented in Matlab are presented. It is followed by a statistical analysis of the acquired results and their respective interpretation.
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Short time Fourier transform for heart rate variability analysis
Osičková, Kristýna ; Slávik, Vladimír (referee) ; Janoušek, Oto (advisor)
The thesis describes the heart rate variability (HRV), its physiological and clinical significance and the means of its analysis. It includes a thorough dissection of the methods applied in the process of HRV evaluation in a time domain and using the short-time Fourier transform. The thesis compare both of the methodologies regarding changes of HRV caused by global ischaemia. The practical part descibes the application created in Matlab for analysis in the time domain and using short-time Fourier transform. The resulsts were calculated from the positions R wave EG signal isolated rabbit hearts.
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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.
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Analysis of intracardiac electrogram, depending on transmurality of ablation lesions at catheter radiofrequency ablation of cardiac arrythmias
Žbánková, Alena ; Kozumplík, Jiří (referee) ; Kolářová, Jana (advisor)
Catheter ablation is a unique method for cardiac arrhythmias treatment based on creating spot lesions of radiofrequency energy using intracardiac ablation catheter. Transmurality of these lesions should be achieved for long-term therapeutic treatment effect. The degree of myocardial damage depth is reflected in the parameters of sensed intracardiac ECG. From research studies is evident that the change in morphology and deflection of ablation signal play a key role in the assessment of transmurality. This thesis consists of theoretical introduction to electrophysiology, proposal and realization of methods for objective assessment of transmurality by processing signals in time, frequency and time – frequency domain. The end of this diploma thesis includes the statistical analysis of these clinical dat and comparison of methods.
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Experimental data processing in real time
Veselý, Petr ; Harabiš, Vratislav (referee) ; Kolářová, Jana (advisor)
The thesis completes the current programming equipment for experimental measurement of isolated animal heart signals. It adds a block providing the pre-processing of the signals. The signals measured are the elektrogram (EG) and the action potential (AP). The origin of individual signals, the measuring method and the possibilities of noise elimination are dealt with in the theoretical part of the thesis. The practical part describes the pre-processing block securing the noise elimination during the AP. It uses accumulative methods of averaging the corresponding time periods of the AP. Based on the results of measuring the signal to noise ratio, the thesis suggests the most appropriate accumulative methods and their variables. In order for the chosen accumulative methods to work well, it is important to divide the AP process into sectors of corresponding shape (repeats). The connection between the EG and AP processes is used to determine the beginning and end of the sectors. These points are identified by the detection of R and T wave peaks in the EG. To detect the R and T waves, the thesis uses methods based on wavelet transform. The efficiency and accuracy of detection methods is verified by test EG signals with hand-marked R and T wave peaks.
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