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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.
111

Respostas agudas da variabilidade da frequência cardíaca após sesão de exercício de força com restrição de fluxo sanguíneo = Acute responses of heart rate variabiblity afer blood flow restriction resistance exercise / Acute responses of heart rate variabiblity afer blood flow restriction resistance exercise

Souza, Luciana Cristina de, 1986- 23 August 2018 (has links)
Orientador: Mara Patrícia Traina Chacon Mikahil / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Física / Made available in DSpace on 2018-08-23T03:14:09Z (GMT). No. of bitstreams: 1 Souza_LucianaCristinade_M.pdf: 3136861 bytes, checksum: 3f028a579a4869dd47ab258e4144ea85 (MD5) Previous issue date: 2013 / Resumo: A redução da Variabilidade da Frequência Cardíaca (VFC) está associada com o alto risco de eventos cardiovasculares, e também ao processo de envelhecimento e ao grau de sedentarismo. A prática regular de exercícios físicos, destacadamente os aeróbios, reflete em um aumento da VFC, decorrente da reduzida atividade simpática quase sempre acompanhada do aumento da atividade parassimpática sobre o coração, tanto em condições de repouso, como após sessão de treinamento. A prescrição do treinamento de força no envelhecimento tem sido prescrito por gerar ganhos de força e hipertrofia diminuindo o risco de lesões e quedas. Nesse sentido, o exercício resistido (RE) associado com uma restrição do fluxo sanguíneo (RE-BFR) tem sido utilizado por proporcionar ganhos de força ou hipertrofia muscular similar ao treinamento tradicional, fazendo uso de intensidades reduzidas de treinamento. Entretanto, pouco se sabe sobre as respostas autonômicas cardiovasculares agudas associadas a este tipo de treinamento. Objetivo: Desta forma, o presente estudo se propôs a comparar as respostas agudas da VFC após sessões de RE tradicional e RE-BFR, utilizando um ou dois exercícios em membros inferiores. Métodos: Quinze homens (47,6±5,28 anos, 76,81±10,95 kg, 1,74±0,08m), saudáveis e não ativos participaram desse estudo. Os voluntários foram submetidos a quatro sessões randomizadas de treinamento, compostas pelos seguintes exercícios: Leg Press de alta intensidade (Leg-HI) (80% 1RM), Leg Press de baixa intensidade com restrição parcial do fluxo sanguíneo (Leg-BFR) (20% 1RM), Extensão do joelho e Flexão de joelho de alta intensidade (EF-HI) (80% 1RM) e Extensão do joelho e Flexão de joelhos de baixa intensidade com restrição parcial do fluxo sanguíneo (EF-BFR) (20% 1RM). Os dados de VFC foram coletados nos momentos pré durante 20min, e imediatamente após a sessão de treinamento durante 60min, na posição supina. A coleta foi feita utilizando monitor Polar® s810 e os dados foram analisados a partir do software Kubios HVR Analysis 1.1. Foi utilizada uma análise da curva de crescimento para expressar o comportamento das variáveis ao longo do período de recuperação, bem como a comparação entre as diferentes sessões de exercício. Foi utilizado o software SAS 9.2. Resultados: A análise da curva de crescimento identificou aumento no índice LFnu para o grupo Leg-HI comparado ao Leg-BFR(P = 0,0033) e EF-BFR(P = 0,0062). O grupo Leg-HI também mostrou maior redução de HFnu comparado ao Leg-BFR (P = 0,0033) e EF-BFR(P = 0,0062). Além disso, houve uma tendência para maior LF/HF para EF-HI comparado ao Leg-BFR(P = 0,0758). Houve efeito de tempo (P=0,0001; P=0,0001; P=0,0067) e efeito de grupo (P=0,001; P=0,0169; P=0,0001) para os índices iRR, SDNN e RMSSD, respectivamente. Entretanto, não houve efeito grupo x tempo para essas variáveis. Conclusões: Os resultados mostraram aumento da modulação simpática e diminuição na modulação parassimpática para Leg-HI quando comparado com ambos os protocolos de RE-BFR após a sessão de exercício. Esses resultados podem ser importantes especialmente para pessoas envelhecendo, visto que o RE-BFR pode ser um método interessante, pois somados aos benefícios neuromusculares já reportados, apresenta menor stress autonômico comparado ao RE de alta intensidade / Abstract: Reduced Heart Rate Variability (HRV) is associated with high risk of cardiovascular events, and also to the aging process and the degree of inactivity. The regular practice of physical exercise, the aerobic prominently, reflects an increase in HRV, due to reduced sympathetic activity almost always accompanied by an increase in parasympathetic activity on the heart, both at rest, and after the exercise session. The prescription of strength training in aging has been prescribed for generating gains in strength and hypertrophy decreasing the risk of injury and falls. Accordingly, the resistance exercise (RE) associated with a restriction of blood flow (RE-BFR) has been used for providing strength gains and muscle hypertrophy similar to traditional training with lower intensity training. However, studies about the acute cardiovascular autonomic responses associated with this type of training are scarce. Objective: Thus, the present study purposed to compare the acute responses of HRV after sessions of traditional RE and RE-BFR, using one or two exercises for lower limbs. Methods: Fifteen men (47.6 ± 5.28 years, 76.81 ± 10.95 kg, 1.74 ± 0.08m), healthy and non-active participated in this study. The volunteers were randomly assigned to four sessions of training, consist of the following exercises: Leg Press high intensity (Leg-HI) (80% 1RM), Leg Press low intensity with partial blood flow restriction (Leg-BFR) (20% 1RM), knee extension and knee flexion high intensity (EF-HI) (80% 1RM) and knee extension and knee flexion low intensity with partial restriction of blood flow (EF-BFR) (20% 1RM). HRV data were collected in pre session during 20min and immediately after session during 60min in the supine position. The collection was made using Polar ® S810 monitor and data were analyzed using the software Kubios HVR Analysis 1.1. Random coefficient growth curve analysis allowed comparison between slopes to express the behavior of variables over the period of recovery, as well as the comparison between different exercise sessions. We used SAS 9.2 software. Results: The analysis of the growth curve identified an increase in LFnu index to Leg-HI compared to Leg-BFR (P = 0.0033) and EF-BFR (P = 0.0062). The Leg-HI group also showed greater reduction in HFnu compared to Leg-BFR (P = 0.0033) and EF-BFR (P = 0.0062). In addition there was a tendency for higher LF/HF compared to EF-HI-Leg BFR (P = 0.0758). There was a time effect (P = 0.0001, P = 0.0001, P = 0.0067) and group effect (P = 0.001, P = 0.0169, P = 0.0001) to iRR, SDNN and RMSSD indices, respectively. However, no significant group vs time effect for these variables. Conclusions: The results showed increased sympathetic modulation and reduced parasympathetic modulation for Leg-HI when compared with both protocols RE-BFR after the exercise session. These results are especially important for aging people, since RE-BFR may be an interesting method because in addition to neuromuscular benefits reported, presented lower autonomic stress compared to RE high intensity / Mestrado / Atividade Fisica Adaptada / Mestra em Educação Física
112

Caracterização da carga física de trabalho na horticultura orgânica / Characterization of the workload on the organic horticulture

Ribeiro, Ivan Augusto Vall 08 August 2011 (has links)
Orientadores: Roberto Funes Abrahão, Mauro José Andrade Tereso / Tesse (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-19T06:14:25Z (GMT). No. of bitstreams: 1 Ribeiro_IvanAugustoVall_D.pdf: 6768277 bytes, checksum: 3276154c8c5da600e316acce986202e0 (MD5) Previous issue date: 2011 / Resumo: Diversas têm sido as pesquisas em agricultura orgânica a partir de perspectivas técnicas, econômicas ou relacionadas aos aspectos ecológicos. No entanto, ainda são raras as investigações que objetivam identificar as características da carga de trabalho na agricultura orgânica, sob uma perspectiva ergonômica. Este projeto buscou caracterizar a carga física de trabalho na horticultura orgânica com base na determinação da frequência de exposição dos trabalhadores às categorias relevantes da atividade. Para tanto, fez-se uma adaptação do método PATH (Posture, Activities, Tools and Handling) para sua utilização na análise do trabalho agrícola. A abordagem incluiu uma avaliação do esforço físico exigido para a execução das tarefas dos diversos sistemas de trabalho por meio de uma amostragem sistemática das situações laborais e da monitoração sincronizada do parâmetro fisiológico frequência cardíaca; caracterização do repertório postural adotado pelos trabalhadores pela adaptação do método OWAS; identificação das áreas do corpo dos trabalhadores que apresentam desconforto pela aplicação do Diagrama das Áreas Dolorosas; avaliação do esforço percebido através da aplicação da escala RPE. Buscou-se correlacionar os resultados das avaliações particulares e interpretá-los à luz da observação da atividade dos trabalhadores. Os resultados sugerem que o método adotado mostrou-se eficiente para caracterizar a carga de trabalho da horticultura orgânica. As exigências posturais foram mais significativas que as cardiovasculares para as tarefas estudadas e se correlacionaram positivamente com as manifestações de desconforto corporal. O desenvolvimento tecnológico para assistir o trabalho humano na horticultura deveria ser priorizado para as tarefas ligadas ao plantio, tratos culturais e à colheita, tanto para minimizar os efeitos deletérios da carga de trabalho, quanto para aumentar a sua produtividade / Abstract: There are many researches on organic agriculture regarding technical, economic or ecological issues; few researches, however, tries to identify the characteristics of the workload in organic agriculture under an ergonomic perspective. This project aimed the characterization of the physical workload in organic horticulture by determining the frequency of exposure of operators to some activity categories. To do this, an adaptation of the PATH method (Posture, Activities, Tools and Handling) was done to be used in the context of agriculture work. The approach included an evaluation of physical effort demanded to perform the tasks in the work systems from an systematic sampling of work situations from a synchronized monitoring of the heart rate; a characterization of posture repertoire adopted by workers by adapting the OWAS method; an identification of pain body areas using the Corlett diagram; and a subjective evaluation of perceived effort using the RPE Borg scale. The results of the individual assessments were cross correlated and explained from an observation of the work activity. The results suggest that the adopted method was efficient to characterize the workload of the organic horticulture. Postural demands were more significant than cardiovascular demands for the studied tasks, and correlated positively with the expressions of bodily discomfort. It is expected that, besides the knowledge obtained of the physical effort demanded by organic horticulture, this project will be useful for the development of new technologies directed to minimize the difficulties of the human work and to raise the work productivity / Doutorado / Planejamento e Desenvolvimento Rural Sustentável / Doutor em Engenharia Agrícola
113

Alterações autonômicas na doença de Machado-Joseph / Autonomic dysfunction in Machado-Joseph

Takazaki, Karen Antonia Girotto, 1979- 21 August 2018 (has links)
Orientadores: Marcondes Cavalcante França Junior, Anamarli Nucci / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-21T18:19:14Z (GMT). No. of bitstreams: 1 Takazaki_KarenAntoniaGirotto_M.pdf: 1348260 bytes, checksum: 48e434fbe077053824d92b0221e439fc (MD5) Previous issue date: 2012 / Resumo: A SCA3/MJD é a ataxia hereditária mais freqüente em nosso meio e apresenta sintomatologia bastante variada, incluindo aspectos motores e não - motores. Dentre estes, ressaltamos a disfunção autonômica, achado pouco estudado e muitas vezes subestimado nestes pacientes. Neste estudo tivemos por objetivos: 1. determinar a frequência e a intensidade das manifestações autonômicas na SCA3/MJD; 2. avaliar se a disfunção autonômica envolve o sistema simpático e/ou o parassimpático; 3.determinar se existe correlação entre as manifestações autonômicas, parâmetros genéticos e clínicos; e 4. verificar se existe correlação entre as manifestações autonômicas e o envolvimento do sistema nervoso periférico. Para isso realizamos uma avaliação clínica e eletrofisiológica em 40 pacientes com confirmação molecular da doença e 38 controles saudáveis pareados por idade e sexo. Ambos os grupos foram submetidos a exame clínico, incluindo o uso da escala SARA (Scale for the Assessment and Rating of Ataxia), o questionário SCOPA-AUT (Scales for Outcomes in Parkinson's Disease - Autonomic Questionnaire), além da aferição da pressão arterial nas posições supina e ortostática. Também realizamos o estudo da variabilidade da frequência cardíaca no repouso, no desafio ortostático (razão 30:15), durante a manobra de Valsalva (índice de Valsalva) e na respiração profunda (razão E:I). Realizamos ainda a análise espectral dos intervalos RR no repouso e a resposta simpática cutânea. As queixas mais frequentes dos pacientes relacionam-se aos sintomas do controle urinário, cardiovascular e sudomotor. Observamos diferença significativa na média dos intervalos RR em repouso dos pacientes em relação aos controles (811,8 x 933,4 ms; p=0,001). A análise da razão 30:15 também mostrou diferença significativa entre os dois grupos (1,10 x 1,15; p=0,038). Já o índice de Valsalva e a razão E:I não mostraram diferença significativa (p=0,373 e p=0,08). A análise espectral mostrou diferença significativa entre os grupos, em relação ao LFPA (poder de baixa frequência), com média de 23,6 x 43,3 ms² (p<0,001), e ao HFPA (poder de alta frequência), com média de 28,8 x 54,4ms² (p<0,001). Obtivemos a frequência de 30% de disautonomia cardiovascular e 45% de disautonomia simpática sudomotora nos pacientes com SCA3/MJD. Verificamos envolvimento tanto do simpático quanto do parassimpático. Não observamos correlação entre as manifestações autonômicas e parâmetros genéticos (tamanho da expansão CAG) ou clínicos, mas encontramos correlação entre disfunção autonômica simpática sudomotora e o envolvimento do sistema nervoso periférico / Abstract: SCA3/MJD is the most frequent autosomal dominant ataxia worldwide and characterized by a variety of symptoms, including motor and non-motor manifestations. Autonomic dysfunction has been described in SCA3/MJD, but there are only small studies and several important questions remain unanswered. In this study we had the following objectives: 1. To determine the frequency and the intensity of the autonomic manifestations in SCA3/MJD. 2. To evaluate whether the autonomic dysfunction compromises the sympathetic and/or the parasympathetic system. 3. To identify possible correlations between the autonomic manifestations, genetic and clinical parameters. 4. To verify whether there is correlation between the autonomic manifestations and peripheral nervous system damage. We have thus performed clinical and electrophysiological evaluation of 40 patients with molecular confirmation of SCA3/MJD and 38 healthy controls matched by age and gender. In the clinical study we used the SARA scale (Scale for the Assessment and Rating of Ataxia), the SCOPA-AUT questionnaire (Scales for Outcomes in Parkinson's Disease - Autonomic Questionnaire), and we measured blood pressure in supine and orthostatic positions. We also studied the heart rate variability at rest, during the orthostatic challenge (30:15 ratio), during the Valsalva maneuver (Valsalva index) and deep breathing (E:I ratio). We included in our study the spectral analysis of the RR intervals at rest and the cutaneous sympathetic response. The most frequent complaints in our patients are related to urinary, cardiovacular and sweat control. We found significant difference of the mean RR intervals at rest between patients and controls (811.8 x 933.4 ms; p=0.001 respectively). The 30:15 ratio was also different between the two groups (1.10 x 1.15; p=0.038 respectively). The Valsalva index and the E:I ratio were similar between the groups (p=0.373 and p=0.08). Spectral analysis presented distinct results in patients and controls, related to LFPA - low frequency power (p<0.001) and to HFPA - high frequency power (p<0.001). We found cardiovascular and sympathetic sweat disautonomia in 30% and 45% of the patients with SCA3/MJD, respectively. We found evidence of both sympathetic and parasympathetic dysfunction. We did not find correlation between autonomic manifestations and genetic (CAG repeat length) or clinical parameters, but we found correlation between sympathetic sweat autonomic dysfunction and peripheral nervous system damage / Mestrado / Neurologia / Mestra em Ciências Médicas
114

Cardiac autonomic regulation and repolarisation during hypoglycaemia in type 1 diabetes

Koivikko, M. (Minna) 05 February 2013 (has links)
Abstract Hypoglycaemia may contribute to the nocturnal occurrence of sudden death in type 1 diabetes. The impact of hypoglycaemia on cardiac autonomic regulation and electrical properties is a potential factor predisposing patients to fatal arrhythmic events.This study was designed to assess the effects of hypoglycaemia on cardiovascular autonomic regulation and cardiac repolarisation in type 1 diabetic patients and their non-diabetic counterparts during experimental and spontaneous hypoglycaemia. Sixteen subjects with type 1 diabetes and eight healthy controls participated in experimental hypoglycaemia induced by using glucose clamp technique. Altogether 37 patients with type 1 diabetes were evaluated in real-life situation by using continuous glucose monitoring system. Ten of those individuals participated in additional experiment to determine the effect of sympathetic activation on the cardiac autonomic regulation. Continous electrogram recordings were used to analyze heart rate variability (HRV) and cardiac repolarisation. During experimental hypoglycaemia, cardiac vagal activity, assessed by the high frequency (HF) component and beat-to-beat R-R interval variability (SD1), decreased progressively with no differences among diabetic or non-diabetic subjects. Controlled hypoglycaemia evoked profound changes in cardiac repolarisation. These changes tended to be even more evident in the diabetic subjects compared to those encountered in their healthy counterparts. During spontaneous hypoglycaemia, the low frequency (LF) component of HRV decreased significantly and correlated positively with the change in the glucose concentration. The muscle sympathetic nerve activity study confirmed that the reduction in the LF spectral component resulted mainly from pure sympathetic activation without any concomitant vagal withdrawal. Spontaneous hypoglycaemia induced significant changes in T-wave loop morphology. The QT interval corrected for heart rate by Bazett´s formula and by the nomogram method shortened during hypoglycaemia. The present observations indicate that hypoglycaemia has major impacts on cardiac autonomic regulation and repolarisation which may partly explain the vulnerability of these individuals to life-threatening cardiac arrhythmias and may have some clinical importance in contributing to the occurrence of ´dead-in-bed` syndrome. / Tiivistelmä Hypoglykemia saattaa vaikuttaa yöllisten äkkikuolemien ilmaantuvuuteen tyypin 1 diabetesta sairastavilla. Hypoglykemian vaikutus sydämen autonomiseen toimintaan ja sähköisiin ominaisuuksiin voi altistaa potilaat kuolemaan johtaville rytmihäiriölle. Tämän tutkimuksen tarkoitus oli selvittää hypoglykemian vaikutuksia kardiovaskulaarisen autonomisen toiminnan säätelyyn ja sydämen repolarisaatioon tyypin 1 diabetesta sairastavilla ja heidän terveillä verrokeillaan kokeellisen ja spontaanin hypoglykemian aikana. Kuusitoista diabetesta sairastavaa ja 8 verrokkipotilasta osallistuivat kokeellisen hypoglykemian tutkimukseen. Yhteensä 37 tyypin 1 diabetesta sairastavaa seurattiin jatkuvan sokeriseurannan laitteella kotioloissa. Kymmenen heistä osallistui jatkotutkimukseen, jossa selvitettiin sympaattisen aktivaation vaikutusta sydämen autonomisen toiminnan säätelyyn. Jatkuvaa sydänfilmin rekisteröintiä käytettiin sydämen sykevaihtelun ja repolarisaation analysoinnissa. Kokeellisen hypoglykemian aikana sydämen vagaalinen aktiivisuus määriteltynä korkean taajuuden (HF) komponentin osuutena ja R-R-välin vaihteluna (SD1) väheni progressiivisesti sekä diabetesta sairastavilla että verrokeilla. Kontrolloitu hypoglykemia aiheutti huomattavia muutoksia sydämen repolarisaatioon. Nämä muutokset olivat jopa suurempia diabetesta sairastavilla kuin heidän terveillä verrokeillaan. Spontaanin hypoglykemian aikana sykevaihtelun matalan taajuuden (LF) komponentin osuus pieneni huomattavasti ja korreloi positiivisesti sokeripitoisuuden muutokseen. Lihaksen sympaattisen hermoston aktiivisuutta koskeva tutkimus vahvisti, että matalan taajuuden osuuden pieneneminen johtui pääasiassa sympaattisesta aktivaatiosta eikä niinkään vagaalisen osuuden pienenemisestä. Spontaani hypoglykemia aiheutti merkittäviä muutoksia T-aallon sähköisen silmukan morfologiaan. Bazett’n kaavalla ja nomogrammimenetelmällä korjattu QT-väli lyheni hypoglykemian aikana. Tehdyt havainnot osoittavat, että hypoglykemialla on sellaisia merkittäviä vaikutuksia sydämen autonomisen toiminnan säätelyyn ja repolarisaatioon, jotka voivat osittain selittää näiden yksilöiden alttiuden henkeä uhkaaville rytmihäiriöille. Näillä muutoksilla voi olla kliinistä merkitystä ns. ”dead in bed”-oireyhtymän esiintymisessä.
115

Personality traits and health outcomes : an exploration into associations and potential mechanisms

Čukić, Iva January 2015 (has links)
There were two main objectives of this thesis. First, given that personality traits have been linked to a number of diabetes risk factors and precursors such as lifestyle and the metabolic syndrome, our aim is to explore whether personality traits are associated with type 1 and type 2 diabetes mellitus. Second, we aim to investigate several potential mechanisms by which personality could influence diabetes, and other health outcomes such as cardiovascular disease and mortality. Chapter 1 provides an introductory overview of the history of personality-health research, and discusses strengths and limitations of different methodological frameworks. Chapters 2-4 focus on the associations between personality and diabetes. Two studies described in Chapter 2 examine cross-sectional and longitudinal associations between personality and type 1 and type 2 diabetes. We used a large national sample with ten years of follow-up. We detected positive associations between openness and neuroticism and type 1 diabetes prevalence, and negative associations between neuroticism and type 2 diabetes incidence. In Chapter 3, we examine relationships between personality and type 2 diabetes incidence using aggregated personality and diabetes data on a level of the U.S. counties and states. In a six-years follow-up study, we found no evidence that mean levels of personality traits were associated with diabetes incidence in the U.S. states. In the following chapter we explore whether a possible mechanism by which personality may influence diabetes is by moderating the expression of its genetic risk. The study described in Chapter 4 looks at interactions between personality domains and facets with polygenic risk score for type 2 diabetes in predicting glycated haemoglobin levels using a large community-dwelling sample. This study found a negative phenotypic correlation between openness and glycated haemoglobin levels, though this association was confounded by cognitive ability. Moreover, genetic risk for diabetes was more strongly associated with glycated haemoglobin levels in people with lower levels of either agreeableness or conscientiousness. In Chapter 5 we move away from diabetes to discuss previously reported contradictory results regarding the effects neuroticism has on mortality. Some of the previous studies reported higher neuroticism being associated with higher risk of mortality, whereas some reported that higher neuroticism was associated with lower risk of death. We tested whether the sign of the neuroticism effect was a function of the covariates included in the models. In a national sample with ten years of follow-up we found that neuroticism was a risk factor for death in the models that did not include objective and self-rated health variables. However, when these variables were included, neuroticism was related to lower risk of death. In the last empirical chapter, Chapter 6, we explore whether autonomic nervous system activity is a biomarker for personality traits. The first study tests whether openness is associated with measures of sympathetic and parasympathetic nervous system activation. We find that openness was associated with sympathetic nervous system activity under baseline but not in the stress conditions, and that it was not associated with measures of parasympathetic activation. The second study describes a model of associations between neuroticism and autonomic nervous system activation, while controlling for cardiovascular disease and depression and their mutual associations. We found that neuroticism has independent contributions to all measures of autonomic nervous system activity, and to heart disease, even when controlling for relevant clinical variables. Thus, autonomic nervous system activity may explain in part observed links between personality, and heart disease and mortality. Finally, in Chapter 7 we summarize the findings presented in the five empirical chapters, discuss the limitations of the current method, and offer suggestions for future research in the field.
116

Analysis of heart rate variability from 24-hour ambulatory electrocardiographic recordings:significance of preprocessing of R-R interval time series

Peltola, M. (Mirja) 11 January 2011 (has links)
Abstract Heart rate variability (HRV) is used in the assessment of cardiovascular health. However, often contradictory results have impeded the efficient use of HRV in clinical practice. HRV signals can contain artifacts leading to errors in the interpretation of HRV results. Various methods have been used for artifact editing, but there is relatively little information on how the actual editing can influence the HRV measures. The main aim of this thesis was to improve the reliability of HRV analysis by concentrating on the HRV signal preprocessing methods. The effects of three editing methods on the HRV of short (512 R-R) and long-term (24-hour) R-R interval data were studied with non-edited and edited data from healthy subjects (n=10) and patients with acute myocardial infarction (AMI) (n=10). The effects of ectopic beats on short (α1) and long-term (α2) fractal scaling exponents were studied by inserting artificial ectopic beats into the HRV signals of 20 healthy subjects and 20 AMI patients. The prognostic significance of edited and non-edited α1 and α2 was studied in random elderly (n=84) and post-AMI (n=84) populations. A new method to quantify respiratory sinus arrhythmia (RSA) was developed based on the HRV signals of 13 healthy subjects. A new measure, the RSA index, was defined to evaluate the risk to sudden cardiac death (SCD) in 1631 AMI patients. Lastly, a new algorithm was developed in order to edit heart rate (HR) turbulence occurring immediately after a ventricular premature beat (VPB). The effects of HR turbulence editing on the HRV analysis were studied in 267 AMI patients. Editing had distinct effects on the HRV analysis depending on the editing method and data type. Deletion editing was found to be unsuitable for the HRV spectrum analysis. There was no universal editing method for the time and frequency domain HRV analyses. Unedited ectopic beats increased the randomness of short-term R-R interval dynamics, especially in AMI patients. However, unedited α1 differed significantly between survivors and those who died during the follow-up. Ectopic beats do not necessarily need to be edited if fractal analysis is used in the risk evaluation. A depressed RSA index was found to be a strong predictor of SCD but a weak predictor of non-SCD in AMI patients. Editing of HR turbulence affected differently the various HRV measures. ULF and VLF components were most clearly influenced by HR turbulence removal. The amount of VBPs had an important impact on the results. When the VBPs/hour were >50, ULF and VLF were >30% lower after turbulence removal. The results of this thesis highlight the importance of editing the erroneous or irrelevant R-R interval oscillation in an HRV analysis. The careful choice of preprocessing method is essential if one wishes to obtain reliable HRV analyses for clinical purposes.
117

Imaging of salivary glands and assessment of autonomic nervous system function in primary Sjögren's syndrome

Niemelä, R. (Raija) 27 February 2004 (has links)
Abstract The purpose of the present study was to find reliable non-invasive methods for imaging salivary glands and diagnosing primary Sj?gren's syndrome (SS) and to evaluate autonomic function and central nervous system (CNS) disorders in patients with primary SS. The patient population consisted of consecutive patients with primary SS, who fulfilled the International classification criteria for primary SS, from the Division of Rheumatology, Department of Internal Medicine in Oulu University Hospital. Magnetic resonance (MR) imaging and MR sialography of parotid glands were performed on 27 patients and 7 healthy controls and ultrasonography (US) of major salivary glands on 27 patients, 27 healthy controls, and 27 symptomatic controls with sicca symptoms or salivary gland swellings without SS. MR imaging and US showed heterogeneous parenchyma or adipose degeneration of the gland in 81% and 78% of patients, respectively. MR sialography showed ductal system changes, narrowings and dilatations, or cavities in 96% of patients. One healthy control and 2 symptomatic controls had abnormal findings of parotid or submandibular glands on US. Other controls had normal findings. The diagnostic specificity of US was 94%. Parenchymal structural changes on MR imaging and US were associated with anti-Ro/SSA positivity and weakly with the focus score index, but not with salivary or tear secretion, age, disease duration, or features of systemic activity of the disease, such as hypergammaglobulinemia or systemic complications. A comprehensive package of cardiovascular tests, including 24-hour heart rate variability, baroreflex sensitivity test with phenylephrine, Valsalva manoeuvre, deep breathing tests, and active orthostatic test, were conducted on 30 patients and 30 healthy, age and sex-matched, randomly selected population-based controls. No signs of autonomic dysfunction were found in patients compared to controls in any of the tests. The test results were not associated with saliva or tear secretion, age, disease duration, or clinical features of systemic activity of the disease. A case of severe inflammatory CNS disease associated with primary SS was described, and an investigation of the relevant literature was made. Though inflammatory CNS disease is a possible complication of primary SS, there is no consensus regarding its prevalence or significance in the literature. Diagnostics and treatment are empiric. In conclusion, MR imaging, MR sialography, and US yield such a definitive picture of the glandular changes in primary SS that they are promising alternatives for invasive examinations in the diagnostics of primary SS. Comprehensive cardiovascular tests revealed no signs of autonomic dysfunction in patients with primary SS compared to general population.
118

Effect of physical exercise on autonomic regulation of heart rate

Hautala, A. (Arto) 07 May 2004 (has links)
Abstract Regular aerobic training has been suggested to protect the heart by increasing cardiac vagal activity. The aims of this study were to evaluate the autonomic regulation of heart rate (HR) during and after exercise, during aerobic training interventions and to study the association between autonomic regulation and the training response in healthy male subjects. HR variability assessment was used to study the effects of exercise on autonomic regulation of HR. The whole study population consisted of 70 volunteer male subjects (age 36 ± 10 years). The recovery of the autonomic nervous system after prolonged exhaustive exercise was studied in a group of 10 subjects. The training interventions included 51 subjects. The effects of training volume on autonomic regulation were assessed (n = 46) during a controlled eight-week training intervention. The association between training and autonomic regulation was studied (n = 24) during a ten-month period of home-based training based on the American College of Sports Medicine recommendations. Finally, the association between autonomic regulation and the individual training response was analysed (n = 51) after eight weeks of controlled training. The recovery rate of vagally mediated high-frequency (HF) power of HR variability after prolonged exhaustive exercise was associated with physical fitness (r = -0.71, P &lt; 0.016). Moderate (3 hours/week) and high-volume (6 hours/week) aerobic training results in a similar increase in HR variability indices. HF power increased from 6.19 ± 1.02 to 6.76 ± 0.96 ln ms2 (P &lt; 0.001) and from 6.61 ± 1.01 to 7.12 ± 0.92 ln ms2 (P &lt; 0.001) after moderate and high-volume training, respectively. During the home-based training program, the changes in HF power were associated with the changes in the fitness (r = 0.44, P &lt; 0.05), body mass index (r = -0.44, P &lt; 0.05) and the amount of training (r = 0.41, p &lt; 0.05). Finally, a significant correlation was observed between the training response and the baseline HF power (r = 0.52, P = 0.001). HF power accounted for 27 % of the change as an independent predictor of the aerobic training response. In conclusion, a highly controlled aerobic training intervention of eight weeks, including six 30-min sessions a week at an intensity of 70–80 % of maximum HR, is a sufficient intervention to increase cardiac vagal outflow and the offered home-based training according the current guidelines maintains the high cardiac vagal outflow. Secondly, high vagal activity at baseline is associated with the improvement in aerobic fitness caused by aerobic training, suggesting that the cardiovascular autonomic function is an important determinant of the response to aerobic training.
119

Non-invasive predictors of mortality after acute myocardial infarction

Tapanainen, J. (Jari) 03 May 2003 (has links)
Abstract There is a need to identify patients with an increased risk of dying after acute myocardial infarction (AMI), because sudden cardiac death (SCD) and potentially fatal ventricular tachyarrhythmias can be prevented by an implantable cardioverter-defibrillator, or in some cases, with aggressively optimized drug or revascularization therapy. The present study was designed to study the predictive power of non-invasive risk markers and all-cause, cardiac and arrhythmic mortality in 700 consecutive post-AMI patients discharged alive with optimal medication according to contemporary guidelines. Detrended fluctuation analysis of heart rate variability (HRV) predicted all-cause mortality beyond clinical variables as well as left ventricular function in post-AMI patients. The predictive power of the short-term scaling exponent α1 was higher than that of the traditional indexes of HRV (for α1 &lt; 0.65, the risk ratio (RR) in multivariate analysis was 5.1, with 95% confidence intervals (CI) 2.9-8.9; p &lt; 0.001). HRV results from a conventional 24-hour electrocardiographic (ECG) recording system differed significantly when compared to a system with a higher sampling frequency. The difference was generally more pronounced in post-AMI patients than in healthy subjects. The presence of sustained T-wave alternans during a predischarge exercise test after AMI was not a marker of mortality. However, the inability to perform an exercise test or to reach the heart rate of 105 beats/min predicted independently all-cause (RR 9.3, 95% CI 2.0-43.3, p &lt; 0.01) and cardiac mortality (RR 11.1, 95% CI 2.4-50.8, p &lt; 0.01). High levels of natriuretic peptides were associated with both sudden and non-sudden cardiac mortality. B-type natriuretic peptide provided more specific independent information on the risk for subsequent SCD (RR 3.9, 95% CI 1.2-12.3, p &lt; 0.05) than non-SCD. SCDs occurred mainly more than 18 months after AMI, and the proportion of SCD was less than 40% of all cardiac deaths. Common arrhythmia markers such as the presence of ventricular premature beats or episodes of nonsustained ventricular tachycardia during ambulatory recordings, the time domain parameters of HRV, baroreflex sensitivity, QT dispersion and QRS complex duration provided only limited predictive power on the risk of SCD or arrhythmic events in patients with optimized beta-blocking therapy. Many risk variables previously considered to predict SCD were better predictors of non-SCD than SCD. Conclusions: 1. The epidemiological pattern of SCD was different from that reported previously. 2. Many arrhythmia risk markers provided only limited information on the risk of SCD. 3. Short-term fractal scaling exponent α1 provided potentially useful information on the risk for all-cause mortality, and BNP was useful in predicting the risk of SCD in a post-AMI population with optimized therapy.
120

Thermal, circulatory, and neuromuscular responses to whole-body cryotherapy

Westerlund, T. (Tarja) 17 March 2009 (has links)
Abstract The purpose of this study was to examine thermal (body temperature, thermal sensation and comfort ratings), circulatory (blood pressure, heart rate variability) and neuromuscular performance responses to whole-body cryotherapy (WBC, -110 °C). Altogether 66 healthy subjects were exposed to WBC for two minutes. The acute and long-term changes were examined, when the subjects were exposed to WBC three times a week during three months. Skin temperatures decreased very rapidly during WBC, but remained such a high level that there was no risk for frostbites. The effects on rectal temperature were minimal. Repeated exposures to WBC were mostly well tolerated and comfortable and the subjects became habituated at an early stage of trials. WBC increased both systolic (24 mmHg) and diastolic (5 mmHg) blood pressures temporarily. Adaptation of blood pressure was not found during three months. The acute cooling-related increase in high-frequency power of RR-intervals indicated an increase in cardiac parasympathetic modulation, but after repeated WBC the increase was attenuated. The repeated WBC exposure-related increase in resting low frequency power of RR-intervals resembles the response observed related to exercise training. There are signs of neuromuscular adaptation, especially in dynamic performance. A single WBC decreased flight time in drop-jump exercise, but after repeated WBC these changes were almost vanished. This adaptation was confirmed by the change of the activity of the agonist muscle, which increased more and the change of the activity of antagonist muscle, which increased less/did not change after repeated WBC indicating reduced co-contraction and thus, neuromuscular adaptation.

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