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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Motion artifact reduction of electrocardiograms using multiple motion sensors

2013 September 1900 (has links)
An electrocardiogram (ECG) is a measurement of the electrical signal produced by the heart as it beats. This is a signal very commonly used by medical professionals, as it gives an indication of an individual’s heart rate and can further be used to detect specific abnormalities within the heart. There are a number of sources of noise that can corrupt the ECG signal, the most problematic being that of motion artifacts. As an individual wearing a surface ECG moves, their movements will add noise to the signal. This noise is particularly difficult to remove, as it will change depending on the movements of the user and will often fall in the same spectrum as the ECG signal itself. The effectiveness of the adaptive filtering method in reducing motion artifacts is investigated using multiple motion sensors on key locations of the body and by combining the motion data through the use of various blind source separation methods. An adaptive filter is a filter that can use a reference signal in order to readjust itself to a constantly changing noise signal and is commonly used to clean ECG signals. The adaptive filter uses noise estimations based on the reference signal as well as previous noise estimations in order to continually clean the noisy signal. Since motion artifacts are based directly off the movements of the user, collected motion data will be directly correlated with the noise being introduced to the ECG, and can therefore be used in the adaptive filter to produce a desirable ECG signal.
22

EKG-Screening för unga idrottare på elitnivå : En systematisk litteraturstudie / ECG-Screening for young elite athletes

Julås, Daniel January 2013 (has links)
ECG-Screening for young elite athletes Abstract Background Sudden cardiac death (SCD) during physical activity is a frightening and emotional tragedy that draws huge media attentions when it occurs. Fortunately it is a relatively uncommon occurrence but happens nonetheless to young athletes who often seems to be in perfect health. SCD is used as a term for sudden unexpected complications on the cardiovascular system that leads to a deadly outcome normally within the first hour of onset of symptoms and the cause is some sort of underlying cardiovascular disease that gets triggered by physical activity.Normally athletes gets divided into two groups dependent on age, over and under 35 years, and this studies focus is on the younger group since it is often during this period athletes are at the elite level. It is also in this category the most unexpected sudden deaths occur that is not due to coronary atherosclerosis, which is the dominant cause of death, and drastically increases, for people over 35 years old. Aim The aim of this study was to scientific and unbiased analyze peer-reviewed clinical articles todescribe the pros, cons and cost to implement an ECG-screening as a standard before physicalactivities for specifically defined elite athletes. Method A systematic review was performed and after all data collection 21 articles was chosen to beused as a base for both background and analyze. At the end 10 articles was fulfilling the criteria to be used at the analyze and later the results. Results The implementation of ECG-screening has reduced SCD in Italy by 89 % between the years 1979-2004. There is a higher risk of SCD for active elite athletes. ECG-screening could be aneffective way to detect hypertrophic cardiomyopathy but a similar study showed oppositeresult. The positive negative results from ECG are relatively low. Hypertrophiccardiomyopathy is a rare disease among elite athletes. A standardized help tool for ECG can help all sorts of physicians in judging the results from ECG. The cost for implementation ofECG-screening for all young athletes is high and will probably not be implemented in countries like USA for a foreseable future. Discussion There is a lot of studies done on the matter but only a couple has shown any positive numbers that gives the implementation of en ECG-screening actually reduce the mortality to SCD. More studies are published every year and the debate will probably go on for a long time, especially concerning money and resources but also about its effectiveness. Better technology in the future will probably make it a more affordable project, especially if it develops to be amore efficient tool.
23

Adaptive cancellation techniques for noise reduction in electrocardiography

Mukalaf, A. January 1987 (has links)
No description available.
24

Normal and Abnormal Findings from Exercise Stress ECG, Post-Exercise Echocardiography and Angiography Studies in a Series of Hypertensive and Normotensive Individuals

Gerni, Angie G. Jr. 09 December 1997 (has links)
The purpose of this investigation was to compare the frequencies of normal and abnormal findings from exercise electrocardiography (ECG), post-exercise echocardiography (ECHO) and angiography studies in a series of hypertensive and normotensive individuals who underwent diagnostic testing. Data for the ECG and ECHO were obtained simultaneously and the angiography was performed either before or following the exercise stress test. Thirty-seven cases were included in this retrospective study. Records were excluded if patients had: history of myocardial infarction; valvular heart disease; ECG evidence of abnormal Q waves, left ventricular hypertrophy (LVH) with abnormal ST/T wave pattern, or left bundle branch block (LBBB); medications that would alter blood pressure responses or ECG interpretation, technically uninterpretable records; or failure to attain 85% of age-adjusted maximal heart rates during the exercise tests. Subjects were defined as hypertensive (HYP) if at least two of the following criteria were met: 1) SBP ≥ 140 mmHg or DBP ≥ 90 mmHg; 2) current use of antihypertensive medications; or 3) history of hypertension. Normotensive subjects (NORM) were defined as absence of the above criteria. Data for the ECG and ECHO variables were obtained simultaneously in association with treadmill exercise studies. In each test, ECG measures were taken at peak exercise while the ECHO data were taken within 90 seconds immediately post exercise to obtain images. ECG response was considered abnormal if the ST shifted ≥ .1 mV from baseline at J₆₀ , while the ECHO response was considered abnormal when new or worsening of pre-existing wall motion abnormalities was observed. The 2-D ECHO's were recorded with the subject in the left lateral decubitus position, and parasternal long- and short-axis apical two and four chamber views were recorded for qualitative determination of wall motion abnormalities. Eleven of the 37 subjects also underwent angiography. Chi-square analysis demonstrated that high blood pressure status did not increase the frequency of abnormal test results for the ECHO (Χ²= 0.00009, DF = 1, p>.05), the exercise ECG (Χ²= 0.07, DF = 1, p>.05) nor for the angiography (Χ²= 0.69, DF = 1, p>.05). These results indicate that resting blood pressure does not influence the occurrence of abnormal vs normal ECG and ECHO findings nor angiography findings between hypertensive and normotensive subjects. There was also no significant differences between the ECG and ECHO in the occurrence of abnormal findings for NORM subjects (Χ²=2.43E-015, DF = 1, p>.05) nor HYP subjects (Χ²=0.13, DF = 1, p>.05). The ECHO showed 80% true-positive findings and the ECG showed 60% compared to the angiography. Both the ECG and ECHO had the same percentage of true-negatives (33%) compared to the angiography results. Since there was a higher percentage of ECHO true-positive results compared to the angiography then the ECG, this may indicate that the ECHO is comparable to the angiography findings and may be a better predictor in determining disease than the ECG. However, these data warrant further evaluation studies. / Master of Science
25

Wireless In-home Ecg Monitoring System with Remote Access

Porter, Logan 08 1900 (has links)
The thesis work details the design and testing of a wireless electrocardiogram (ECG) system. This system includes a wireless ECG device, as well as software packages to visually display the waveform locally on a computer and remotely on a web page. The remote viewing capability also extends to using an Android phone application. The purpose of the system is to serve as a means for a doctor or physician to check up on a patient away from a hospital setting. This system allows for a patient to be in their home environment while giving health vital information, primarily being the heart’s activity through the ECG, to medical personnel.
26

Notch Filter Design for Power Line Interference Artifact Reduction of ECG Signal and Feature Extraction in LabVIEW

Kasidi, Divyasri 05 1900 (has links)
Electrocardiogram (ECG) is a biological signal that represents the heart's electrical activity. Interference from power lines introduces a frequency component of 50 to 60 Hz into the signal, which is the principal cause of ECG corruption. By using the Cadence Virtuoso Spectre circuit simulator and typical TSMC RF 180 nm CMOS technology, a notch filter was created to reduce powerline interference. The advantage of utilizing a notch filter for PLI is that noise at 60 Hz is completely eliminated without sacrificing any important information. Additionally, this study contains a MATLAB-based model for, which is used to compute the power spectral density for the obtained time-domain signal. By incorporating power spectral density into data gathering procedures, it is feasible to enhance data collection methodologies, construct models that appropriately account for observed power and aid in the removal of undesired components. NI LabVIEW is used to extract features. The advantage of ECG feature extraction is that it provides information that assists in the identification of cardiac rhythm issues, and gives information about the occurrence of heart attack. In this study, several patient data sets are utilized to extract characteristics and provide information regarding heart condition abnormalities.
27

Electrocardiography, ECG Interpretation and Applications

Sefat, Farshid January 2014 (has links)
yes / The aim of this book is to be able to interpret Electrocardiograms avoiding all possible errors. The accuracy of the interpretation is of great importance but a true diagnosis is far more significant. This book focuses on the recognition and interpretation of arrhythmias, one of the most important clinical tools in medicine. The greatest degree of accuracy is achieved by familiarising with the normal ECG that enables the recognition of abnormal patterns to be made immediately. Firstly, it is necessary to acquaint the function of the heart and the electrical activity in order to broaden our understanding of how the ECG detects this electrical activity. It is essential to know the characteristic patterns of a normal ECG and to categorise a wide array of morphologic patterns along with determining abnormal ECG patterns to be diagnostic of particular pathological entities. A series of practical experiments have been carried out on various subjects using the BIOPAC system to record electrical signals of the heart. Subjects were asked to perform various tasks such as lying down, sitting, deep breathing and exercising to detect electrical signals in different conditions and eventually interpret the data. The ethical issue toward each subject is also too important, so it was necessary to let the subject know about any risk factors during experiment. For this purpose, a Volunteer Information Sheet was designed during this work for each subject to read and be aware of all the ethical issues. Also, another Patient Consent Form was designed to make sure that each volunteer fully understands the procedures. Volunteer Questionnaire is necessary to make sure volunteer that there is no problem, which can affect the experimental results. Finally, ECG results were interpreted using a systematic approach and the precise findings were correlated with the pathophysiology and clinical status of the patient. This book concludes with a thorough investigation into the essential techniques and skills required to accurately interpret an ECG, eliminating as many errors as possible.
28

A 018μm Cmos Transmitter for Ecg Signals

Kakarna, Tejaswi 12 1900 (has links)
Electrocardiography (ECG) signal transmitter is the device used to transmit the electrical signals of the heart to the remote machine. These electrical signals are ECG signals caused due to electrical activities in the heart. ECG signals have very low amplitude and frequency; hence amplification of the signals is needed to strengthen the signal. Conversion of the amplified signal into digital information and transmitting that information without losing any data is the key. This information is further used in monitoring the heart.
29

Análise diferencial da expressão gênica e proteica no corpo lúteo de bovinos submetidos a tratamentos com eCG / Differential analysis of the gene and protein expression in bovine corpus luteum under eCG treatments

Fátima, Luciana Alves de 04 September 2012 (has links)
A gonadotrofina coriônica equina (eCG) tem sido utilizada em programas de sincronização para inseminação artificial em tempo fixo e normalmente promove o aumento do volume do corpo lúteo e a da produção de progesterona. Além disso, esta mesma gonadotrofina pode ser utilizada para superovulação. Desse modo, hipóteses relativas aos mecanismos pelos quais gonadotrofinas exógenas alteram as funções celulares nos corpos lúteos resultantes foram formuladas. Para testar tais hipóteses, 18 vacas (Bos indicus) foram divididas em grupos: controle (n=5), estimulado (n=6) e superovulado (n=7) e a ovulação das mesmas foi sincronizada usando um protocolo já estabelecido com dispositivo de progesterona. Os animais estimulados receberam 400 UI de eCG no dia de remoção do dispositivo de progesterona e os animais superovulados 4 dias antes. No dia 7 após injeção de GnRh, os animais foram abatidos para a coleta de CLL e sangue. Análises de peso e volume de CL, concentração de progesterona (P4), bem como da expressão gênica e proteica de fatores angiogênicos e de proteínas esteroidogênicas foram realizadas. Além disso, o transcriptoma foi analisado por microarranjo. Foi observado que o volume do CL foi maior nos animais do grupo estimulado (1177,37 ± 167,07 mm3) e ainda maior nos do superovulado (1495,18 ± 137,01 mm3) quando comparados ao grupo controle (830,33 ± 234,99 mm3; p = 0,03). A concentração média de progesterona por CL nos animais do grupo estimulado foi maior que nos animais do grupo controle (5,95 ± 0,17 vs 3,69 ± 0,72 ng/ml; p = 0,03) e que nos superovulados (4,11 ± 0.73; p = 0,01). Além disso, os tratamentos com eCG aumentaram a expressão do FGFR2 e também da STAR nos animais estimulados e superovulados (p < 0,05). Quanto aos resultados do microarranjo, no total 242 transcritos foram aumentados e 111 foram diminuídos nos animais estimulados e 111 foram aumentados e 113 diminuídos nos animais superovulados em relação aos animais controle (~1,5 vezes, p 0.05). Entre os genes diferencialmente expressos, muitos estavam envolvidos na síntese de lipídios e na produção de progesterona, tais como: PPARG, HMGCR, STAR, receptores de prolactina e folistatina. Estes achados demonstraram que os tratamentos com eCG modularam a expressão gênica diferencialmente, dependendo do tratamento, e que nossos dados contribuem para entender as vias relacionadas ao aumento do volume do CL e da produção de progesterona observada após os tratamentos. Em um segundo experimento, foi realizado análises da influência do FSH na expressão de VEGF no cultivo de células da granulosa. Neste experimento foi possível observar que o FSH aumentou a expressão gênica e proteica do VEGF, colaborando com a ideia de que as gonadotrofinas têm propriedades angiogênicas. / Equine chorionic gonadotropin (eCG) has been widely used in synchronization protocol to artificial insemination program and usually promote corpus luteum (CL) volume increases and stimulates progesterone production. Furthermore the same gonadotropin can be used to superovulation protocols. Thus, hypotheses concerning the mechanisms by which exogenous gonadotropins alter cellular functions in resulting corpora lutea were formulated. To test that hypothesis, 18 (Bos indicus) cows were divided into control (n=5), stimulated (n=6) and superovulated groups (n=7). Ovulation was synchronized using a progesterone device-based protocol. Stimulated animals received 400 IU of eCG of device removal and superovulated animals received 2000 IU of eCG 4 days prior. Corpora lutea (CLL) and blood samples were collected seven days after GnRH administration. Analyses of CL weight and volume, progesterone (P4) concentration, as well as the gene and protein expression of angiogenic and steroidogenic proteins were performed. Furthermore, the transcriptome was evaluated by microarray. The CL volume was higher in superovulated (1495.18 ± 137.01) than in stimulated (1177.37 ± 167.07) cows and higher in stimulated than in the control (830.33 ± 234.99) cows, and the P4 concentration per CL was higher in stimulated (5.95 ± 0.17 ng/ml) animals than in the control (3.69 ± 0.72 ng/ml) and superovulated (4.11 ± 0.73 ng/ml; P = 0.01) animals. Overall, 242 transcripts were up-regulated and 111 transcripts were downregulated in stimulated cows (P 0.05) and 111 were up-regulated and 113 down-regulated in superovulated cows in relation to the control (1.5 fold, P 0.05). Among the differentially expressed genes, many were involved in lipid biosynthesis and progesterone production, as PPARG, HMGCR, STAR, prolactin receptors and follistatin. In conclusion, eCG modulates gene expression differently depending on the treatment. Our data contribute to the understanding of the pathways involved in increased CL volume and progesterone levels observed after eCG treatment. In a second experiment, analyzes were performed about the influence of FSH on the expression of VEGF in the culture of granulosa cells. In this experiment it was observed that FSH increases the expression of the VEGF gene and protein, these finding collaborate with the idea that gonadotrophins have angiogenic properties.
30

Desenvolvimento de protocolos para IATF com 7 dias de permanência do CIDR® em fêmeas Nelore / Protocol development for TAI with 7 days of CIDR® in Nellore cows

Santos, Marcelo Henrique dos 01 April 2016 (has links)
O objetivo do experimento I foi avaliar a redução do tempo de permanência do dispositivo de P4 de 9 para 7 dias sob parâmetros reprodutivos de vacas Nelore. Foram utilizadas 674 vacas lactantes entre 40-60 dias pós parto que receberam no início do protocolo (d0) BE + CIDR. No momento da retirada do CIDR foi administrado PGF2 &#945;, ECP e eCG. A IATF ocorreu 55 e 48 horas após a retirada do dispositivo nos tratamentos 7d-CIDR e 9d-CIDR, respectivamente. Dez dias após a IA foi realizada colheita de sangue para dosagem de P4 sérica e confirmação da ovulação. Vacas tratadas com 7d-CIDR apresentaram menor (p < 0,01) folículo ovulatório em relação ao 9d-CIDR. No entanto, a concentração de P4 pós-IA, taxas de ovulação, detecção de estro e prenhez não foram influenciadas pelo tempo de permanência do CIDR. Assim, o uso do CIDR por 7 dias promoveu desempenho reprodutivo semelhante em vacas Nelore comparado ao protocolo com 9 dias. O experimento II teve o objetivo de avaliar os efeitos da reutilização do CIDR por até 35 dias de uso em vacas e 42 dias em novilhas Nelore. Utilizou-se 749 vacas lactantes 40-60 dias pós parto e 92 novilhas púberes. No d0 os animais receberam BE + CIDR novo (CIDR1) ou previamente usado por 7 (CIDR2), 14 (CIDR3), 21 (CIDR4), 28 (CIDR5) e 35 (CIDR6) dias. No momento da retirada do CIDR (d7) foi administrado PGF2 &#945;, ECP, eCG e exame de US para mensuração do maior folículo (FD), além de colheita de sangue para dosagem de P4. A IATF ocorreu 55 horas após a retirada do dispositivo. O diâmetro do FD foi maior (p < 0,01) de acordo com o maior número de usos do CIDR nas vacas, a concentração de P4 reduziu nos CIDRs reutilizados porém se mantiveram acima de 1,5 ng/ml e a taxa de prenhez não foi afetada pela reutilização do dispositivo por até 5 vezes em vacas e o sexto uso em novilhas. O protocolo com 7 dias de permanência permite a reutilização do CIDR por até 6 vezes mantendo a mesma eficiência reprodutiva. No experimento III o objetivo foi avaliar se a aplicação do eCG dois dias antes da retirada do dispositivo aumenta o tamanho do FO, CL e taxa de prenhez. Foram utilizadas 681 vacas lactantes 40-60 dias pós parto e 182 novilhas púberes. Os animais foram distribuídos em dois tratamentos com aplicação de eCG no quinto (5d-eCG) ou sétimo dia (7d-eCG). No d0, os animais receberam BE + CIDR e no dia 7 o CIDR foi retirado e administrado PGF2 &#945; e ECP. Dez dias após a IA foi realizada US para mensuração do CL e colheita de sangue para dosagem de P4. A IATF ocorreu 55 horas após a retirada do dispositivo. O tratamento 5d-eCG aumentou (p < 0,01) o FO nas vacas em relação ao grupo 7deCG e o mesmo ocorreu nas novilhas. Em vacas, a concentração de P4 pós IA foi mais alta (p = 0,04) no 5d-eCG. Em novilhas o diâmetro do CL pós-IA foi maior (p < 0,01) no 5d-eCG. No entanto, a antecipação da aplicação do eCG foi eficiente em aumentar o folículo ovulatório no momento da IATF, mas não aumentou a taxa de prenhez / The aim of the experiment I was to evaluate the reduction of the time of P4 device from 9 (9d-CIDR) to 7 (7d-CIDR) days and its impacts on reproductive parameters of Nellore cows. Six hundred and seventy-four suckling cows 40-60 days postpartum received EB + CIDR at d0 of the protocol. At CIDR removal, there were administered PGF2 &#945;, ECP, eCG. The FTAI occurred 55 and 48 hours after device removal in the treatment 7d-CIDR and 9d-CIDR, respectively. Ten days after AI blood samples were collected for P4 analysis and ovulation rate. Cows of treatment 7d-CIDR showed lower (p <0.01) ovulatory follicle (OF) than 9d-CIDR. The CIDR length in cows and heifers did not influence concentration of P4, ovulation rate, estrus detection rate and pregnancy rate. Thus, the use of CIDR by 7 days did not impacted reproductive result in suckling cows and Nellore heifers. The aim of experiment II was to evaluate the effects of the CIDR reuse up to 35 days in cows and heifers on reproductive characteristics. We used 749 suckling cows 40-60 days postpartum and 92 pubertal heifers. In d0 animals received EB + new CIDR (CIDR1) or previously used by 7 (CIDR2), 14 (CIDR3), 21 (CIDR4), 28 (CIDR5) and 35 (CIDR6) days. At CIDR removal were administered PGF2 &#945;, ECP, eCG and US to measure the largest follicle (LF), and blood collection for P4 analysis. The TAI occurred 55 hours after device removal. The LF diameter was greater (p <0.01) in CIDR reused in cows. P4 concentration was lower in CIDR reused, but was higher than 1.5 ng / mL, and the device reused up to 5 times in cows and 6 times heifers did not affect pregnancy rate. The 7d-CIDR protocol allowed the reuse of CIDR up to 6 times keeping the same efficiency of CIDR new. In the experiment III the objective was to evaluate whether the application of eCG two days before the device removal increases the size of OF, CL and pregnancy rates. Six hundred and eighty-one suckling cows 40-60 days postpartum and 182 pubertal heifers were used. The animals were divided into two treatments with eCG application in fifth (5d-eCG) or seventh day (7d-eCG) of protocol. In d0, the animals received EB + CIDR and day 7 CIDR was removed and administered PGF2 and ECP. Ten days after AI, US was performed to measure the size of CL and blood collection for P4 analysis. The TAI occurred 55 hours after CIDR removal. The treatment d5 eCG increased (p < 0.01) OF. In cows, the concentration of P4 after AI was higher (p = 0.04) in 5d-eCG. In heifers, the CL diameter was higher in 5d-eCG. However, the 5d-eCG did not increase (p > 0.1) pregnancy rate. The strategy of eCG application in d5 was efficient to increase ovulatory follicle, but did not increase pregnancy rate

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