|
|
SMV-2018-19: Systém for ECG analysis
Plešinger, Filip ; Jurák, Pavel ; Halámek, Josef ; Viščor, Ivo
A subject of this contracional research is development of algorithms for automated ECG processing from 1-lead ECG holters. Namely, it consists of:\n- development of algorithm for QRS recognition with focus on robustness against noise\n- development of classification algorithm to recognize arrhythmias, the algorithm is based on analysis of RR intervals and other ECG descriptors. The algorithm implements machine learning (neural networks). The input is Information related to QRS complexes and other descriptors extracted from ECG. The output is category of classified ECG block (atrial fibrillation, AB-block, non-quality signal, premature atrial contractions, premature ventricular contractions, sinus rhythm, supraventricular tachycardia and ventricular tachycardia)\n- Implemetation of these algorithms as software for .NET platform in C# language. It is optimized for multi-thread computers (computing server of the customer).\n
|
|
|
Efficient implementation of Stockwell Transform for real-time embedded processing of physiologic signals
Holmes, D. ; Pinto, S.C. ; Felton, Ch. ; Smítal, L. ; Leinveber, P. ; Jurák, Pavel ; Gilbert, B. ; Haider, C.
Physiologic monitoring enables scientists and physicians to study both normal and pathologic signals of the body. While wearable technologies are available today, many of these technologies are limited to data collection only. Embedded processors have minimal computational capabilities. We propose an efficient implementation of the Stockwell Transform which can enable real-time time-frequency analysis of biological signals in a microcontroller. The method is built upon the fact that the Stockwell Transform can be implemented as a compact filter bank with pre-computed filter taps. Additionally, due to the long tails of the gaussian windowing function, low amplitude filter taps can be removed. The method was implemented on a TI MSP430 processor. Simulated ECG data was fed into the processor to demonstrate performance and evaluate computational efficiency.
|
|
|
Hemodynamic modelling in the calf — A pilot study
Matějková, M. ; Jurák, Pavel ; Soukup, L. ; Halámek, Josef ; Viščor, Ivo ; Langer, P. ; Vondra, Vlastimil
With increasing age, the cardiovascular system loses its efficiency. The goal of this work was to investigate the hemodynamic system response to a head-up tilt test in two groups of different aged people. We used a model for describing this response in the right calf based on a non-invasive, non-occlusive, bioimpedance signal measurement technique. A decrease in the bioimpedance value in the calf during the head-up tilt test is associated with the accumulation of blood in the calf, which can be expressed by a model parameter. Subjects were examined in both a head-up tilt test and a supine position. 50 healthy non-smoking volunteers were divided into two groups according to age. The impedance signal during the tilt test for each subject was fitted by a model exponential function: Z0 model EF(t) =A exp(-t/B)+C, where Z0 model EF(t) is the calculated model of electrical impedance in the calf by an exponential function, A is the amplitude of impedance change, B is the time constant of the impedance decrease, C is the value of the steady state after the tilt test and t denotes time. A lower time constant B shows a faster filling of the vascular system in the investigated part. The Mann-Whitney test (p-value<;0.005) revealed that the time constant B for the older group was significantly lower than for the young group (145.24+/- 80.28 vs. 239.23+/-136.59 sec.). A lower time constant value means a faster response to blood filling in the lower limbs and directly reflects decreased vessel elasticity. This time constant was lower in the older group. The results show increased vessel stiffness in old age and could lead to a non-invasive evaluating the cardiovascular system state.
|
|
|
Biventricular pacing optimization by means of the dyssynchrony parameter
Jurák, Pavel ; Leinveber, P. ; Halámek, Josef ; Plešinger, Filip ; Postránecká, T. ; Lipoldová, J. ; Novák, M.
To improve Cardiac Resynchronization Therapy (CRT), different interventricular delay (VVD) settings can be used. However, relatively small VVD induced hemodynamic changes cannot be measured by standard echocardiographic methods. The QRS complex duration (QRSd) is mostly the main criterion. Here we introduce a new dyssynchrony parameter (DYS) that is able to more accurately detect improved electrical synchrony. Methods: 12-lead 5 kHz ECG during 3-10 minute rest period was measured in 46 patients with CRT OFF and CRT ON with VVD 0 ms (CRT0) and -20 ms (CRT20). We detected QRSd and the dyssynchrony parameter DYS as the time difference between 500-1000 Hz averaged envelopes positions in the V1 and V6 leads in the QRS complex region. Results: 32 of 46 patients had a positive CRT response manifested by QRSd shortening and a DYS decrease. 28 of 32 patients had a positive LV pre-excitation effect: additional QRSd shortening of 4.7+/-.9 ms and a DYS decrease of 12.6+/-7.5 ms. The correlation coefficient of QRSd and DYS changes (CRT 0 vs CRT 20) was 0.23 and indicates information diversity. The DYS parameter differs from QRSd and provides a significantly higher response to VVdelay changes (p <; 0.001).
|
|
|
Desk for splitting semiautomatic
Jurák, Pavel ; Vlašic, František (referee) ; Dvořáček, Jiří (advisor)
The subject of the bachelor thesis is the design of the working table, which will ensure the stem lifting and its transport to the splitting semi-automat. Lifting of stem with weight up to 500 kg is ensured by lifting arms. Then, the stem is moved to the splitting semi-automatic by means of a belt conveyor. The design of the frame is designed to withstand a load of 5000 N. The lowest security has k = 1.2 according to the strength analysis. The table frame can be easily folded using a hydraulic cylinder. Thanks to this we can easily mount the frame behind a splitter semi-automatic and transport both devices at the same time.
|
|
| |
|
|
Possibilities for the use of modern music in liturgy
Jurák, Pavel ; Minářová Výborná, Terezie (advisor) ; Eliáš, Vojtěch (referee)
Surname and name of author: JURÁK Pavel Institution: Department of Pastoral Theology and Law Sciences, Catholic Theological Faculty, Charles University in Prague Title: Possibilities of application of modern music in liturgy Supervisor: Mgr. Bc. Terezie Minářová Výborná Number of pages: 82 Number of bibliographical sources: 67 Keywords: sacred music, liturgy, modern music, active participation, Christian youth This diploma thesis deals with the possibilities of application of modern music in liturgy. The introductory part is dedicated to definitions of the basic terms connected with the sacred music. The next part gives the information on history of liturgical music from the Last Supper. It shows how this music was in its history influenced by the profane elements. It concentrates on interventions of the Church aimed against their penetration in liturgy. The third part of the theses describes in detail attributes of the liturgical music and how this music has been traditionally utilized during the Holy Mass and other liturgical configurations. The attention is also dedicated to term participatio actuosa and ot its importance to the liturgical singing. The main part of the thesis is focused on the possibilities of application of modern music in liturgy. As a model for the incorporation of this...
|
|
|
Detection of High-Frequency EEG Activity in Epileptic Patients
Cimbálník, Jan ; Kremláček, Jan (referee) ; Jiruška,, Přemysl (referee) ; Jurák, Pavel (advisor)
Tato práce se zabývá automatickou detekcí vysokofrekvenčních oscilací jakožto moderního elektrofyziologického biomarkru epileptogenní tkáně v intrakraniálním EEG, jehož vizuální detekce je zdlouhavý proces, který je ovlivněn subjektivitou hodnotitele. Epilepsie je jedním z nejčastějších neurologických onemocnění postihující 1 % obyvatelstva. Přestože jsou přibližně dvě třetiny případů léčitelné farmakologicky, zbylá třetina pacientů je odkázána zejména na léčbu chirurgickým zákrokem, pro nějž je zapotřebí přesně lokalizovat ložisko patologické tkáně. Vysokofrekvenční oscilace jsou v posledním desetiletí studovány pro jejich potenciál lokalizace patologické tkáně. Součástí této práce je shrnutí dosavadního výzkumu vysokofrekvenčních oscilací a výčet detektorů používaných ve výzkumu. V rámci práce byly vyvinuty či vylepšeny tři detektory vysokofrekvenčních oscilací, na jejichž popis navazuje evaluace z hlediska shody s manuální detekcí, přesnosti výpočtu příznaků oscilací a schopnosti lokalizace patologické tkáně. V závěru práce jsou představeny vyvinuté metody vizualizace vysokofrekvenčních výskytu oscilací a stručně uvedeny dosažené vědecké výsledky.
|
|
|
Comparing of the parameters for the determination of cardiac dyssynchrony from the ultra-high-frequency electrocardiogram
Jančová, Ivana ; Viščor,, Ivo (referee) ; Jurák, Pavel (advisor)
This thesis deals with the analysis of high-frequency ECG, namely by parameters for the determination of cardiac asynchrony from the amplitude envelopes ultra-high-frequency ECG. In the theoretical part is described the conventional and high-frequency ECG, procedure of their scanning and parameters of the acquired record. Also is described the electrical conduction system of the heart and its blockade. This issue is followed by chapters about cardiac asynchrony and its treatments by biventricular pacemaker – resynchronization therapy. The chapter about resynchronization includes a description of the methods used for the indication for therapy based on conventional and high-frequency ECG. In the practical part are proposed new parameters for determining heart asynchrony from high-frequency ECG, programmed their detection in environment MATLAB and described realization of detection and obtained results. In the last part of thesis is described statistical evaluation of data and is decided about suitability of use the proposed parameters.
|
|
|
Evaluation of pulse wave velocity in the human body
Mezuláníková, Radka ; Viščor,, Ivo (referee) ; Jurák, Pavel (advisor)
This Mater's thesis deals with the evaluation of pulse wave velocity using multi-channel whole-body impedance cardiography. Data were taken from the group of healthy volunteers whose impedance changes were measured during rest, respiratory maneuvers, tilt and stress exercise. The result of this measurement are values of peaks of pulse wave time shifts towards R-wave. The velocity values towards the thorax electrodes were recalculated on the basis of knowledge about the pulse wave time shifts and the distances from the heart to the scanned locations, which were measured using the arterial segment's lengths.
|
guest ::
RSS feed.