To circumvent some inherent problems in the conventional ECG, this research reinvestigates an ‘unassisted’ approach which enables ECG measurement without the placement of leads on the body. Employed in this research is a widely accepted assumption that the electrical activity of the heart may be represented, largely, by a 3-D time-varying current dipole (3D-CD). From the PhysioBank database, mECG and fECG data were obtained, and Singular Value Decomposition (SVD) was performed to estimate the time-varying Vector ECG dipole. To determine the sensing matrix responsible for transforming the activity of the 3D-CD into the potential distribution on the surface of the medium, the ECG vector dipole signals are used to excite a 3D-CD in water medium of a specific shape-containing-ellipsoid model(s) in COMSOL tool. The sensing matrix thereby estimated is then utilized to reconstruct the 3D-CD signals from the signals measured by the probes on the surface of the medium. Fairly low NRMSEs (Normalized Root-Mean-Squared Errors) are attained. The approach is also successfully extended to the case of two ellipsoids, one inside the other, representing a pregnant female subject. Low NRMSEs (Normalized Root-Mean-Squared Errors) are again observed.

La fibrillation atriale est la plus fréquente des arythmies cardiaques et sa physiopathologie reste mal comprise. Il n’existe pas actuellement de modèle animal dans lequel cette arythmie survienne de manière spontanée. Comme l’âge et l’hypertension artérielle sont deux facteurs de risque majeurs dela fibrillation atriale chez l’Homme, nous avons recherché si le rat spontanément hypertendu (SHR)vieillissant (11-13 mois d’âge) développe cette pathologie. Des enregistrements télémétriques de 24 h de l’électrocardiogramme (ECG) ont été réalisés dans 4 groupes de rats vigils. Ils ont révélé chez le rat SHR vieillissant la présence de nombreux épisodes de tachyarythmie atriale non soutenus, épisodes qui ne sont pas observés chez le rat SHR jeune ni chez lerat normotendu Wistar Kyoto jeune ou vieillissant. Les résultats rapportés ci-dessus ont été obtenus grâce à l’analyse visuelle de l’intégralité de chaque enregistrement ECG, ce qui représente une durée d’analyse incompatible avec des expérimentations de routine. Nous avons donc choisi de développer une méthode automatique de reconnaissance des arythmies atriales chez le rat vigil. Cette méthode utilise exclusivement les intervalles RR car les ondes P ne peuvent pas toujours être identifiées avec fiabilité dans les enregistrements télémétriques de l’ECG. Elle repère les motifs caractéristiques de tachyarythmie grâce à une structure d’automate, et présente une bonne performance sur les enregistrements télémétriques déjà réalisés. Le nouveau modèle animal, conjointement à la nouvelle méthode automatique d’analyse de l’ECG, devrait permettre de réaliser les analyses phénotypiques de qualité indispensables aux hypothèses physiopathologiques moléculaires actuellement avancées dans la fibrillation atriale. / Atrial fibrillation is the most common cardiac arrhythmia and its pathophysiology is still poorly understood. To date, there is no animal model in which the arrhythmia occurs spontaneously. As ageand hypertension are major risk factors of atrial fibrillation in humans, we examined whether the aging (11-13 months of age) spontaneously hypertensive rat (SHR) develops this pathology. Telemetric recordings of electrocardiogram (ECG) were obtained in four groups of conscious rats. They revealed the presence in the aging SHR of many non-sustained atrial tachyarrhythmic episodes that were observed neither in the young SHR nor in the young or aging normotensive Wistar Kyotorat. These results were obtained by visual examination of the whole ECG recordings, which is extremely time consuming and thus, not compatible with routine experiments. Therefore, we chose to develop an automated method to detect atrial arrhythmias in the conscious rat. This method only uses RR intervalsbecause P waves cannot always be accurately identified in telemetric recordings. It recognizes characteristicpatterns of tachyarrhythmia by using an automaton structure, and shows a good performance when applied to previously collected telemetric data. The new animal model, together with the new, automated method of ECG analysis, are expected to be extremely useful for producing high quality phenotypic data, which are necessary to test present molecular hypotheses of atrial fibrillation pathophysiology.

Made available in DSpace on 2016-01-26T18:55:31Z (GMT). No. of bitstreams: 1 Dissertacao.pdf: 489642 bytes, checksum: 095c84cd0f391c63e5fde8b3263ef666 (MD5) Previous issue date: 2011-08-01 / The lack or absence of physical activity in dogs, combined with a diet high in energy has seriously affected the health of dogs, taking them to the development of various problems associated with the heart. This study aimed to study the activity of serum enzymes creatine kinase (CK), creatine kinase MB fraction (CK-MB), lactate dehydrogenase (LDH) and glutathione peroxidase (GSH-Px), before and after short duration exercise, evaluating them with electrocardiographic findings such as heart rate (beats / minute), duration of P-R interval (seconds), heart rate and variation of the T wave in 8 healthy dogs. Heart rate, P-R segment size, heart rates and percentage of T wave, did not change during exercise. It can be concluded that exercise of short duration conducted with prior training of animals modified values of CK, CK-MB and LDH, probably caused by muscle injury due to physical exertion and increased GSH-Px was caused by increased production of free radicals due to the higher oxygen consumption by the body during physical effort. / A falta ou ausência de atividade física de cães, aliada a uma alimentação de alto valor energético, têm afetado seriamente a saúde destes, levando-os ao desenvolvimento de vários problemas associados ao coração. O presente estudo teve como objetivo estudar a atividade das enzimas séricas creatino quinase (CK), creatino quinase fração MB (CK-MB), lactato desidrogenase (LDH) e glutationa peroxidase (GSH-Px), antes e após a realização de exercício de curta duração, avaliando-os com os achados eletrocardiográficos tais como frequência cardíaca (batimentos/minuto), duração do intervalo PR (segundos), ritmo cardíaco e variação da amplitude de onda T em 8 cadelas hígidas. A freqüência cardíaca, tamanho do segmento PR, ritmos cardíacos e percentuais de onda T, não se alteraram durante o exercício. Pode-se concluir que o exercício físico de curta duração realizado com treinamento prévio dos animais modificou os valores das enzimas CK, CK-MB e LDH, provavelmente pela lesão causada no músculo devido ao esforço físico intenso e o aumento da GSH-Px foi ocasionado pela maior produção de radicais livres em virtude do maior consumo de oxigênio pelo organismo durante o esforço físico.

Made available in DSpace on 2016-07-18T17:53:08Z (GMT). No. of bitstreams: 1 Dissertacao.pdf: 489642 bytes, checksum: 095c84cd0f391c63e5fde8b3263ef666 (MD5) Previous issue date: 2011-08-01 / The lack or absence of physical activity in dogs, combined with a diet high in energy has seriously affected the health of dogs, taking them to the development of various problems associated with the heart. This study aimed to study the activity of serum enzymes creatine kinase (CK), creatine kinase MB fraction (CK-MB), lactate dehydrogenase (LDH) and glutathione peroxidase (GSH-Px), before and after short duration exercise, evaluating them with electrocardiographic findings such as heart rate (beats / minute), duration of P-R interval (seconds), heart rate and variation of the T wave in 8 healthy dogs. Heart rate, P-R segment size, heart rates and percentage of T wave, did not change during exercise. It can be concluded that exercise of short duration conducted with prior training of animals modified values of CK, CK-MB and LDH, probably caused by muscle injury due to physical exertion and increased GSH-Px was caused by increased production of free radicals due to the higher oxygen consumption by the body during physical effort. / A falta ou ausência de atividade física de cães, aliada a uma alimentação de alto valor energético, têm afetado seriamente a saúde destes, levando-os ao desenvolvimento de vários problemas associados ao coração. O presente estudo teve como objetivo estudar a atividade das enzimas séricas creatino quinase (CK), creatino quinase fração MB (CK-MB), lactato desidrogenase (LDH) e glutationa peroxidase (GSH-Px), antes e após a realização de exercício de curta duração, avaliando-os com os achados eletrocardiográficos tais como frequência cardíaca (batimentos/minuto), duração do intervalo PR (segundos), ritmo cardíaco e variação da amplitude de onda T em 8 cadelas hígidas. A freqüência cardíaca, tamanho do segmento PR, ritmos cardíacos e percentuais de onda T, não se alteraram durante o exercício. Pode-se concluir que o exercício físico de curta duração realizado com treinamento prévio dos animais modificou os valores das enzimas CK, CK-MB e LDH, provavelmente pela lesão causada no músculo devido ao esforço físico intenso e o aumento da GSH-Px foi ocasionado pela maior produção de radicais livres em virtude do maior consumo de oxigênio pelo organismo durante o esforço físico.

The aim of this thesis is to analyse high-frequency ECG to detect some heart diseases. This is performed with averaging of selected QRS complexes for each lead of the signal; these are thenfilteredin range 500-1 000 Hz. After that the envelope of the signal is done and here the peaks are detected. Based on mutual positions of this peaks, it is possible to detectwhat kind od signal we treat.

The aim of this thesis is to analyse high-frequency ECG to detect some heart diseases. This is performed with averaging of selected QRS complexes for each lead of the signal; these are then filtered in range 500-1 000 Hz. After that the envelope of the signal is done and here the peaks are detected. Based on mutual positions of this peaks, it is possible to detect what kind od signal we treat.

Main objective of this thesis was to learn about possibility of suppression of narrow band disturbances. We focused on use of Lynn’s filters. The objective was to realize these filters with respect to a fast algorithm of filtering. Concretely, for suppression of drift we realized the fast high pass filter with flexible cut off frequency. Then we realized filter for suppression of electrical network disturbance. We have realized these filters for sampling frequencies 250 and 500 Hz and we tested them with real ECG signals. Then we have evaluated their efficiency.

Objective of this diploma work was to study methods of adaptive filtering and their use in suppression of noise in biological signals. Adaptive filtering represents effective means of suppression of parasitic nonstationary disturbances in a useful signal. The task was to design various types of adaptive filters and implement an adaptation algorithm in Matlab programming environment. It namely included suppression of powerline noise at 50 Hz and 100 Hz in ECG signals with minimization useful components disturbing. The realized filters were verified on real ECH signals and their efficiency was evaluated.

The aim of this diploma work is the suggestion and realization of a cardiostimulator of „On Demand“ type operated by microcontroller. The work is structured on four thematic parts. For the correct suggestion of the whole system, firstly is necessary to understand correctly the cell’s electrophysiology and heart’s anatomy, inclusive the cardiology arrhytmia, which are adherent to cardiostimulators. The cardiostimulator is inhibited by the R-wave and is adaptive on a pulse rate of a source signal. The whole system is supplied by batteries and this supplying is taken into consideration. The network’s functionality is realized on the ECG simulator. There are suggested the suitable enhancements in discussion.

This thesis deals with implementation of detector QRS complex with use of wavelet transform. The first part is focused on formation and possibility to measure cardiac activity. The other part of thesis we will familiarise with the different possibilities of detection QRS complex and we intimately focus on wavelet transform that will be used for a project of detection QRS complex. The practical part of thesis focuses on the project of detector in programming language Matlab and his different setting. This projected detector has been tested with CSE database. Achieved results of projected detector are evaluated with the results of others authors.