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Influence of Parasympathetic Modulation in Doppler Mitral Inflow Velocity in Individuals without Heart Disease

ANTELMI, Ivana; YAMADA, Alice Tatsuko; HSIN, Chang Nan; TSUTSUI, Jeane M.; GRUPI, Cesar Jose; MANSUR, Alfredo Jose
Fonte: MOSBY-ELSEVIER Publicador: MOSBY-ELSEVIER
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
37.298408%
Background: The relation between left ventricular filing velocities determined by Doppler echocardiography and autonomic nervous system function assessed by heart rate variability (HRV) is unclear. The aim of this study was to evaluate the influence of the autonomic nervous system assessed by the time and frequency domain indices of HRV in the Doppler indices of left ventricular diastolic filling velocities in patients without heart disease. Methods: We studied 451 healthy individuals (255 female [56.4%]) with normal blood pressure, electrocardiogram, chest x-ray, and treadmill electrocardiographic exercise stress test results, with a mean age of 43 +/- 12 (range 15-82) years, who underwent transthoracic Doppler echocardiography and 24-hour electrocardiographic ambulatory monitoring. We studied indices of HRV on time (standard deviation [SD] of all normal sinus RR intervals during 24 hours, SD of averaged normal sinus RR intervals for all 5-minute segments, mean of the SD of all normal sinus RR intervals for all 5-minute segments, root-mean-square of the successive normal sinus RR interval difference, and percentage of successive normal sinus RR intervals > 50 ms) and frequency (low frequency, high frequency, very low frequency, low frequency/high frequency ratio) domains relative to peak flow velocity during rapid passive filling phase (E)...

Características da fadiga de pacientes com insuficiência cardíaca; Fatigue characteristics of heart failure patients

Fini, Andréa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 12/05/2008 Português
Relevância na Pesquisa
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INTRODUÇÃO: A fadiga é freqüente em pessoas com insuficiência cardíaca e limita a manutenção de um estilo de vida compatível com senso desejável de autonomia e independência. O controle das limitações funcionais é prioridade no cuidado à pessoa com insuficiência cardíaca, mas não há estudos sobre fadiga em amostras de pacientes brasileiros. OBJETIVO: Caracterizar a fadiga em pacientes com insuficiência cardíaca e comparar sua freqüência e intensidade com voluntários sem doença. MÉTODO: Estudo descritivo-exploratório, com 300 pacientes ambulatoriais. (masculino=68,3%, idade média de 54,8(±11,5) anos, escolaridade média de 6,0(±4,1) anos; Classe Funcional I= 44,7%) e 64 voluntários sem doença, acompanhantes de pacientes ambulatoriais (masculino=34,4%, idade média de 33,3(±10,7) anos, escolaridade média de 10,2(±3,2) anos). Foi aplicado instrumento com as escalas de fadiga (Dutch Fatigue Scale - DUFS) de fadiga ao esforço (Dutch Exertion Fatigue Scale - DEFS), o Inventário de Depressão de Beck (IDB), instrumento de avaliação da atividade física (International Physical Activity Questionnaire) e itens para avaliação da dispnéia, tabagismo e terapia medicamentosa. As escalas DUFS e DEFS foram adaptadas para o Brasil e mostraram propriedades psicométricas adequadas (consistência interna...

Desenvolvimento de sistemas bio-telemétricos para a medida da freqüencia cardíaca e do ritmo respiratório.; Development of Biotelemetric systems for the measure of the cardiac frequency and the respiratory rhythm.

Costa, Gláucia Grüninger Gomes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/02/1986 Português
Relevância na Pesquisa
46.86983%
O desenvolvimento da Física tem possibilitado sua atuação em vários campos, e mais recentemente, na Medicina, onde estudos da Freqüência Cardíaca e do Ritmo Respiratório fornecem informações importantes acerca de processos fisiológicos e podem ser um útil instrumento diagnóstico e terapêutico. Nestes estudos, em muitos casos, necessita-se que as variáveis sejam monitoradas telemétricamente, como a observação de atletas e pacientes pré e pós-enfartados durante a prática desportiva, e estudos de animais em seu habitat natural. Desenvolvemos, portanto, um protótipo capaz de medí-las por métodos não invasivos (métodos que dispensam urna exposição cirúrgica), baseando-se na aplicação do Efeito Doppler Ultrasônico e no Movimento Mecânico do Tórax. Este protótipo consta de um conjunto de transmissores e receptores que captam e Freqüência Cardíaca e o Ritmo Respiratório, registrando de forma audível, gráfica e numérica, conforme tempos pré-estabelecidos.; The development of physics made action in various fields possible, and more recently, in Medicine, studies of heart frequency and breathing rhythm give important information about physiological status and are useful for diagnostics and therapeutics. In these studies...

Efeito do manejo pré-abate sobre alguns parâmetros fisiológicos em fêmeas suínas pesadas

Dalla Costa, Osmar Antonio; Ludke, Jorge Vitor; Coldebella, Arlei; Kich, Jalusa Deon; Costa, Mateus José Rodrigues Paranhos da; Faucitano, Luigi; Peloso, José Vicente; Dalla Roza, Darlan
Fonte: Universidade Federal de Santa Maria (UFSM) Publicador: Universidade Federal de Santa Maria (UFSM)
Tipo: Artigo de Revista Científica Formato: 852-858
Português
Relevância na Pesquisa
46.81754%
O objetivo neste trabalho foi avaliar o efeito do período de descanso (3, 5, 7 e 9 horas) dos suínos no frigorífico (PDF) e da localização dos suínos na carroceria do caminhão (PBO), quando transportados, no inverno ou verão, sobre alguns parâmetros fisiológicos avaliados em 64 fêmeas, com peso médio de 130kg para abate, durante o manejo pré-abate. Para a análise estatística, foram considerados, no modelo de análise da variância, os efeitos de bloco, PDF, PBO e da interação (bloco x PDF), entre outros. O PDF influenciou, significativamente, as concentrações de lactato no sangue e cortisol na saliva. Suínos que descansaram 5 e 7 horas apresentaram maior concentração de lactato em relação aos animais que descansaram 3 e 9 horas. No transporte, a freqüência cardíaca foi muito maior em relação aos demais locais avaliados. Concluiu-se que o incremento do PDF não promove mudanças na freqüência cardíaca, nas concentrações de glicose e CPK no sangue e cortisol na saliva, mas interfere na concentração de lactato no sangue dos suínos.; The aim of the research was to evaluate the effect of pig lairage time (PDF=3, 5, 7 and 9 hours) and evaluate the effect of pig position into the truck (PBO) during transportation to slaughterhouse...

Respostas fisiológicas durante a prática de Kitesurf

Hilário, Henrique
Fonte: Instituto Politécnico de Santarém Publicador: Instituto Politécnico de Santarém
Tipo: Dissertação de Mestrado
Publicado em //2013 Português
Relevância na Pesquisa
47.178765%
MESTRADO EM DESPORTO, ESPECIALIZAÇÃO EM DESPORTO NATUREZA; RESUMO As exigências fisiológicas em desportos aquáticos têm vindo a ser estudadas a fim de possibilitar, melhor e maior conhecimento das respostas orgânicas, por forma a auxiliar os atletas e praticantes das diversas atividades, na sua preparação física. O objetivo deste estudo foi identificar as exigências fisiológicas impostas pela modalidade de kitesurf. Para tal, dez indivíduos de elite realizaram um teste máximo em passadeira e um teste em água com percurso delineado, com a duração de 30 min e com uma velocidade de vento entre os 16-25 nós. O consumo de oxigênio (VO 2 ) foi calculado a partir da frequência cardíaca (FC) registada durante o teste em água usando a relação individual FC-VO2 determinada durante o teste máximo de esforço. A média de valores da FC e o VO2 estimado representam, respetivamente, 80,31±3,19% da frequência cardíaca máxima e 67,64±5,00% de consumo máximo de oxigênio para velocidades de bordo que variam de 16 e 25 nós. Este estudo sobre Kitesurf sugere que a exigência energética é principalmente sustentada pelo metabolismo aeróbio durante uma condição de vento moderado.; ABSTRACT The physiological demands of water sports have been studied so as to enable and improve the knowledge of organic responses to help prepare athletes and practitioners of different activities. The aim of this study was to identify the physiological demands of kite surf. To do so...

Respostas fisiológicas durante a prática de Kitesurf

Hilário, Henrique
Fonte: Instituto Politécnico de Santarém Publicador: Instituto Politécnico de Santarém
Tipo: Dissertação de Mestrado
Publicado em //2013 Português
Relevância na Pesquisa
47.178765%
Dissertação apresentada para a obtenção do grau de Mestre em Desporto com especialização em Desporto de Natureza; Orientador: Professor Doutor João Brito; RESUMO As exigências fisiológicas em desportos aquáticos têm vindo a ser estudadas a fim de possibilitar, melhor e maior conhecimento das respostas orgânicas, por forma a auxiliar os atletas e praticantes das diversas atividades, na sua preparação física. O objetivo deste estudo foi identificar as exigências fisiológicas impostas pela modalidade de kitesurf. Para tal, dez indivíduos de elite realizaram um teste máximo em passadeira e um teste em água com percurso delineado, com a duração de 30 min e com uma velocidade de vento entre os 16- 25 nós. O consumo de oxigênio (VO2) foi calculado a partir da frequência cardíaca (FC) registada durante o teste em água usando a relação individual FC-VO2 determinada durante o teste máximo de esforço. A média de valores da FC e o VO2 estimado representam, respetivamente, 80,31±3,19% da frequência cardíaca máxima e 67,64±5,00% de consumo máximo de oxigênio para velocidades de bordo que variam de 16 e 25 nós. Este estudo sobre Kitesurf sugere que a exigência energética é principalmente sustentada pelo metabolismo aeróbio durante uma condição de vento moderado.; ABSTRACT The physiological demands of water sports have been studied so as to enable and improve the knowledge of organic responses to help prepare athletes and practitioners of different activities. The aim of this study was to identify the physiological demands of kite surf. To do so...

Heart rate variability and arrhythmias evaluated with Holter in dogs with degenerative mitral valve disease

Oliveira,M.S.; Muzzi,R.A.L.; Araújo,R.B.; Muzzi,L.A.L.; Ferreira,D.F.; Silva,E.F.
Fonte: Universidade Federal de Minas Gerais, Escola de Veterinária Publicador: Universidade Federal de Minas Gerais, Escola de Veterinária
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2014 Português
Relevância na Pesquisa
37.289524%
Cardiac diseases promote alterations in the autonomic control of the heart, leading to an increase in heart rate and, as a result, a decrease in heart rate variability (HRV).The aim of this study was to evaluate if the development of heart failure secondary to degenerative mitral valve disease (DMVD) concurs with changes in autonomic modulation of heart rhythm which are assessed by long electrocardiography examination (Holter). Dogs were evaluated by clinical examination and echocardiography in order to be categorized into the following groups: Control (healthy; n=6), DMVD (disease without heart failure; n=8), and DMVD heart failure (disease with heart failure; n=13). Arrhythmias and frequency domain HRV were determined by Holter. Diseased animals, when compared to healthy, had significantly lower total power, which indicates overall HRV. DMVD heart failure dogs also showed other disturbances such as high incidence of supraventricular arrhythmias, high heart rate, little amount of pauses (2.0s long between consecutive heartbeats), longer time in tachycardia, shorter time in bradycardia, low high frequency (parasympathetic control), and high low frequency (sympathetic and parasympathetic control) when compared to control (p<0.05). In DMVD dogs...

Changes in oxygen saturation and heart frequency during sleep in young normal subjects.

Gimeno, F; Peset, R
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1984 Português
Relevância na Pesquisa
46.688545%
Changes in oxygen saturation and heart frequency were measured during sleep in a group of 21 normal subjects (9 women and 12 men) aged 19-25. At the time of the investigation all were non-smokers, they had no respiratory complaints, and indices of lung function (lung volumes, volume-pressure diagram, and diffusing capacity for carbon monoxide) were within normal limits. In contrast to published data, there were no major changes in oxygen saturation and no differences between men and women.

Coil occlusion of systemic venous collaterals in hypoplastic left heart syndrome

Andrews, R E; Tulloh, R M R; Anderson, D R
Fonte: Copyright 2002 by Heart Publicador: Copyright 2002 by Heart
Tipo: Artigo de Revista Científica
Publicado em /08/2002 Português
Relevância na Pesquisa
46.68268%
Objective: To assess the frequency of systemic venous collaterals to the atria, which may cause desaturation, after stage II reconstructive surgery for hypoplastic left heart syndrome (HLHS) and to determine whether coil occlusion prevents the need for surgical ligation.

Non-invasive assessment of ventricular force–frequency relations in the univentricular circulation by tissue Doppler echocardiography: a novel method of assessing myocardial performance in congenital heart disease

Cheung, M M H; Smallhorn, J F; McCrindle, B W; Van Arsdell, G S; Redington, A N
Fonte: Copyright 2005 by Heart Publicador: Copyright 2005 by Heart
Tipo: Artigo de Revista Científica
Publicado em /10/2005 Português
Relevância na Pesquisa
46.896924%
Objective: To describe the first clinical application of a novel tissue Doppler derived index of contractility, isovolumic acceleration (IVA), in the assessment of the ventricular myocardial force–frequency relation (FFR) in the univentricular heart (UVH).

A Simple and Novel Method to Monitor Breathing and Heart Rate in Awake and Urethane-Anesthetized Newborn Rodents

Zehendner, Christoph M.; Luhmann, Heiko J.; Yang, Jenq-Wei
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 03/05/2013 Português
Relevância na Pesquisa
37.200188%
Rodents are most useful models to study physiological and pathophysiological processes in early development, because they are born in a relatively immature state. However, only few techniques are available to monitor non-invasively heart frequency and respiratory rate in neonatal rodents without restraining or hindering access to the animal. Here we describe experimental procedures that allow monitoring of heart frequency by electrocardiography (ECG) and breathing rate with a piezoelectric transducer (PZT) element without hindering access to the animal. These techniques can be easily installed and are used in the present study in unrestrained awake and anesthetized neonatal C57/Bl6 mice and Wistar rats between postnatal day 0 and 7. In line with previous reports from awake rodents we demonstrate that heart rate in rats and mice increases during the first postnatal week. Respiratory frequency did not differ between both species, but heart rate was significantly higher in mice than in rats. Further our data indicate that urethane, an agent that is widely used for anesthesia, induces a hypoventilation in neonates whilst heart rate remains unaffected at a dose of 1 g per kg body weight. Of note, hypoventilation induced by urethane was not detected in rats at postnatal 0/1. To verify the detected hypoventilation we performed blood gas analyses. We detected a respiratory acidosis reflected by a lower pH and elevated level in CO2 tension (pCO2) in both species upon urethane treatment. Furthermore we found that metabolism of urethane is different in P0/1 mice and rats and between P0/1 and P6/7 in both species. Our findings underline the usefulness of monitoring basic cardio-respiratory parameters in neonates during anesthesia. In addition our study gives information on developmental changes in heart and breathing frequency in newborn mice and rats and the effects of urethane in both species during the first postnatal week.

CT coronary angiography in patients with suspected angina due to coronary heart disease (SCOT-HEART): an open-label,parallel-group, multicentre trial

Scot-Heart Investigators
Fonte: Elsevier Publicador: Elsevier
Tipo: info:eu-repo/semantics/article; all_ul_research; ul_published_reviewed
Português
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57.135073%
peer-reviewed; Background The benefi t of CT coronary angiography (CTCA) in patients presenting with stable chest pain has not been systematically studied. We aimed to assess the eff ect of CTCA on the diagnosis, management, and outcome of patients referred to the cardiology clinic with suspected angina due to coronary heart disease. Methods In this prospective open-label, parallel-group, multicentre trial, we recruited patients aged 18–75 years referred for the assessment of suspected angina due to coronary heart disease from 12 cardiology chest pain clinics across Scotland. We randomly assigned (1:1) participants to standard care plus CTCA or standard care alone. Randomisation was done with a web-based service to ensure allocation concealment. The primary endpoint was certainty of the diagnosis of angina secondary to coronary heart disease at 6 weeks. All analyses were intention to treat, and patients were analysed in the group they were allocated to, irrespective of compliance with scanning. This study is registered with ClinicalTrials.gov, number NCT01149590. Findings Between Nov 18, 2010, and Sept 24, 2014, we randomly assigned 4146 (42%) of 9849 patients who had been referred for assessment of suspected angina due to coronary heart disease. 47% of participants had a baseline clinic diagnosis of coronary heart disease and 36% had angina due to coronary heart disease. At 6 weeks...

Power spectral analysis of heart rate variability in children and adolescents with IDDM

Wawryk, A.; Bates, D.; Couper, J.
Fonte: AMER DIABETES ASSOC Publicador: AMER DIABETES ASSOC
Tipo: Artigo de Revista Científica
Publicado em //1997 Português
Relevância na Pesquisa
37.18776%
OBJECTIVE: To investigate power spectral analysis (PSA) of heart rate variability (HRV) in children and adolescents with IDDM, its relationship with other measures of HRV and standard cardiovascular responses, and factors associated with reduced HVR. RESEARCH DESIGN AND METHODS: A total of 130 subjects with IDDM aged 12.8 +/- 3.2 years and 108 healthy control subjects were studied. Power spectra were analyzed from supine electrocardiograph (ECG) recordings by processing into consecutive R-R intervals and analysis using fast Fourier transformation. Standard cardiovascular responses to deep breathing and standing were performed. RESULTS: IDDM subjects had a reduction in total power including both low-frequency (0.05-0.14 Hz; P = 0.0001) and high-frequency (0.14-0.40 Hz; P = 0.0002) components. These changes were seen from diagnosis. Other measures of HRV, coefficient of variation (CV) and standard deviation (SD) of mean resting heart rate, were also significantly lower in IDDM. All 20 (15%) of the 130 IDDM subjects with total power less than the 5th percentile in control subjects also had reduced HRV when measured by CV of heart rate. There was an independent relationship between age and the high-frequency component in IDDM subjects and control subjects. Total power correlated with mean heart rate (r = -0.56; P < 0.0001)...

The modification of heart rate variability in normal, overweight and type 2 diabetic individuals.

Sjoberg, Nicholas J.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2013 Português
Relevância na Pesquisa
37.306304%
The aim of this thesis was to improve our understanding of the effects that dietary therapies have on improving cardiac autonomic activity in healthy and diabetic people, particularly the effects of omega 3 polyunsaturated fatty acids (PUFA) on healthy people. Research conducted to date suggests that diet has specific effects on cardiac autonomic activity; however, much of this research has ignored the underlying influence of specific therapies and weight loss. In this thesis, heart rate variability (HRV) is used to assess cardiac autonomic activity. Cardiac autonomic activity is chiefly responsible for the beat to beat control of heart rate and has been implicated in sudden cardiac death and prognosis of an adverse cardiovacular event following myocardial infarct. The first experiment was designed to systematically examine the dose-response changes in cardiac ANS activity and vascular compliance after supplementation with omega 3 polyunsaturated fatty acids. In sixty seven overweight middle aged volunteers, HRV, cardiac sympathetic activity (assessed via low frequency component of HRV), parasympathetic activity (assessed by the high frequency component of HRV), Low Frequency/High Frequency (LF/HF) ratio (representing the balance of sympathetic/parasympathetic nervous activity on heart rate)...

Automatic Heart Sound Analysis for Cardiovascular Disease Assessment

Kumar, Dinesh
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
37.438345%
Cardiovascular diseases (CVDs) are the most deadly diseases worldwide leaving behind diabetes and cancer. Being connected to ageing population above 65 years is prone to CVDs; hence a new trend of healthcare is emerging focusing on preventive health care in order to reduce the number of hospital visits and to enable home care. Auscultation has been open of the oldest and cheapest techniques to examine the heart. Furthermore, the recent advancement in digital technology stethoscopes is renewing the interest in auscultation as a diagnosis tool, namely for applications for the homecare context. A computer-based auscultation opens new possibilities in health management by enabling assessment of the mechanical status of the heart by using inexpensive and non-invasive methods. Computer based heart sound analysis techniques facilitate physicians to diagnose many cardiac disorders, such as valvular dysfunction and congestive heart failure, as well as to measure several cardiovascular parameters such as pulmonary arterial pressure, systolic time intervals, contractility, stroke volume, etc. In this research work, we address the problem of extracting a diagnosis using anal-ysis of the heart sounds. Heart sound analysis consists of three main tasks: i) identification of non-cardiac sounds which are unavoidably mixed with the heart sound during auscultation; ii) segmentation of the heart sound in order to localize the main sound component; and finally...

Time-frequency and point process algorithms for cardiac arrhythmia analysis and cardiorespiratory control

Kodituwakku, Sandun
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (PhD); Doctor of Philosophy (PhD)
Português
Relevância na Pesquisa
37.233594%
Cardiovascular diseases are major causes of disability and premature death globally. In particular, atrial fibrillation is the most common cardiac arrhythmia condition found in clinical practice, and is associated with an increased risk of stroke. Heart rate variability (HRV) and respiratory sinus arrhythmia (RSA) are important indicators of cardiovascular health, and provide useful information on autonomic nervous system inputs to cardiac cycle and cardiorespiratory coupling, respectively. New methods to support the treatment of cardiovascular diseases and identifying efficient ways of measuring cardiovascular health could yield significant benefits. In this thesis, we present a number of advanced algorithms for cardiorespiratory signal processing. We present algorithms for analyzing atrial fibrillation arrhythmia from electrocardiograms (ECG). We propose an orthonormal basis function based representation for fibrillatory waveforms, and use a regularized least square solution for atrial activity extraction from ECG, suppressing more dominant ventricular components. Time-frequency analysis of atrial activity is used to identify and track fibrillatory frequencies from extracted atrial activity, which provides possible guidance to tailored treatments. In addressing the problem of tracking fibrillatory frequencies...

Recognition of heart sound based on distribution of Choi-Williams

Chen,Tianhua; Xiang,Lingzi; Zhang,Meina
Fonte: Sociedade Brasileira de Engenharia Biomédica Publicador: Sociedade Brasileira de Engenharia Biomédica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2015 Português
Relevância na Pesquisa
37.247297%
IntroductionTo realize noninvasive diagnosis and early diagnosis of coronary heart disease, the study proposes a new time-frequency method for analyzing heart sound signals. This method is based on Choi-Williams Distribution (CWD).MethodsCWD distribution is developed and modified from Wigner Ville distribution (WVD). To solve the problem of cross-term interference existing in WVD there is an improved version of WVD, called Choi-Williams Distribution (CWD), which introduces the smoothing window as the kernel function and deals with the time-frequency analysis of heart sound signal.ResultsThe improved method has good performance and can be implemented simply without much increase of operation complexity.ConclusionIn this paper, 21 cases of heart sound signals are acquired from the outpatients and hospitalized patients with coronary heart diseases. The research results of 21 cases show that the CWD method can be used to analyze heart sounds. It accurately identifies the 9 cases of heart sounds of health people and 12 cases of heart sounds of patients with coronary heart disease. Besides, the CWD displays obvious differences between heart sounds of healthy people and abnormal heart sounds. The contour line of heart sounds from healthy people shows the following characteristics: concise...

Treinamento muscular inspiratório em pacientes com insuficiência cardíaca: estudo de caso; Inspiratory muscle training for patients with heart failure: a case study

Granville, Daniela Diello; Grünenwald, Paula Girardi; Leguisamo, Camila Pereira; Calegari, Leonardo
Fonte: Universidade de São Paulo. Faculdade de Medicina Publicador: Universidade de São Paulo. Faculdade de Medicina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 31/12/2007 Português
Relevância na Pesquisa
46.736455%
A insuficiência cardíaca (IC) pode ser definida como uma síndrome clínicacomplexa, caracterizada pela incapacidade de o coração ejetar quantidadesuficiente de sangue para atender às necessidades metabólicas dos diferentes tecidos. Pacientes com IC podem apresentar força muscular inspiratória diminuída, o que contribui para os sintomas de fadiga e dispnéia observados durante o esforço ou na realização das atividades de vida diária. Este estudo de caso teve por objetivo verificar a influência do treinamento muscular inspiratório (TMI) em três pacientes com diagnóstico clínico de IC, que foram avaliados no pré e póstreinamento por manovacuometria, ergoespirometria e os índices de Base (IBD) e de Transição de Dispnéia (ITD). O TMI foi realizado durante 12 semanas, 7 vezes por semana com 30 minutos de duração e incremento semanal de carga de 30% da pressão inspiratória máxima (PImáx). Ao final do TMI, constatou-se aumento da PImáx e melhora na pontuação do IBD e ITD nos três pacientes. A melhora da intolerância ao esforço, representada pela redução do duplo produto, da freqüência cardíaca e o aumento no tempo de teste foi verificada em dois pacientes. Não houve alterações no consumo máximo de oxigênio e a ventilação foi reduzida em um dos pacientes. Conclui-se que...

Spectral analysis of heart rate variability: Acquisition/analysis software development

DeLong, David James
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
37.337246%
This work develops an acquisition/analysis software application to investigate the spectral content of the heart rate variability signal derived from an electrocardiographic (EKG) waveform. The location and strength of the frequency content reveals general information concerning sympathetic and parasympathetic activity within the autonomic nervous system of the study subject. Current investigations into pediatric head trauma patients have revealed specific correlations between spectral content of the heart rate variability and overall patient recovery. The levels of serum catecholamines, specifically epinephrine and norepinephrine, are also investigated for a possible correlation with both trauma severity and spectral power of the heart rate variability signal. Two frequency regions are of particular interest in the power spectral density waveform, the low frequency band (0.01-0.15 Hz) and the high frequency band (0.15-0.50 Hz). The low frequency band is indicative of sympathetic nervous system activity (such as body temperature and arterial blood pressure regulation) as well as some parasympathetic nervous system activity. The high frequency band is indicative of parasympathetic activity (such as respiratory sinus arrhythmia) only. In fact...

Time-frequency distribution analysis of heart rate and blood velocity variabilities in stage 24/34 chick embryos

Bonacci, Andrew
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
37.329287%
Time-frequency distribution (TFD) analysis is a relatively new process for decomposing a complex signal to understand its spectral content Traditional signal spectral analysis examines both temporal and spectral contents distinctly. This method of analysis is suitable for signals where the spectral content is stationary and time-invariant. However, many naturally occurring signals are not only multicomponent, but are also highly time-variable, such as speech, heart rate variability, and other biological signals. Typically, the Fourier transform exposes sinusoidal frequencies present in a signal. It cannot, however, tell when these frequencies existed temporally. This is where timefrequency analysis excels over traditional spectral processing techniques. Time-frequency analysis allows the spectral content of the signal to be determined as well as when these frequency components occurred. The process can be thought of as time dependent Fourier analysis. The following thesis explores the effectiveness of time-frequency analysis for examining heart rate and blood velocity variability of dorsal aortic blood flow in developing chick embryos. These hemodynamic data series are used to assess embryonic cardiovascular function.. It is hoped that this thesis aids in the creation of cluneal tools for the early identification of functional heart defects in a developing human fetus. These heart defects can lead to serious heart disease later in life. Clinical treatments of morphological and functional heart defects are possible if they can be identified during early embryo/fetal development The time-frequency analysis performed...