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Role of the cardiac nerve in the adaptive changes of heart rate in response to an aversive stimulus in Megalobulimus mogianensis

ROMERO, S.M.B.; HOFFMANN, A.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.13%
The effect of an aversive stimulus represented by contact with a hot plate on the heart rate of Megalobulimus mogianensis was evaluated with electrocardiogram recording in intact snails (N = 8). All stimulated animals showed an increase in heart rate, with mean values ranging from 35.6 ± 1.2 (basal heart rate) to 43.8 ± 0.9 bpm (post-stimulation heart rate). The cardioacceleration was followed by gradual recovery of the basal heart rate, with mean recovery times varying from 4.3 ± 0.3 to 5.8 ± 0.6 min. Repetition of the stimulus did not affect the magnitude of variation nor did it influence the basal heart rate recovery time. To investigate the role of the cardiac nerve in mediating the heart rate alterations induced by the aversive stimulus, denervated (N = 8) and sham-operated (N = 8) animals were also tested. Although the aversive stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (4.4 ± 0.4 bpm) was 57% of the value obtained in sham-operated animals (7.7 ± 1.3 bpm), indicating that the cardiac nerve is responsible for 43% of the cardioacceleration induced by the aversive stimulus. The cardioacceleration observed in denervated snails may be due to an increase in venous return promoted by the intense muscular activity associated with the withdrawal response. Humoral factors may also be involved. A probable delaying inhibitory effect of the cardiac nerve on the recuperation of the basal heart rate is suggested.

The relationship between heart rate reserve and oxygen uptake reserve in heart failure patients on optimized and non-optimized beta-blocker therapy

CARVALHO, Vitor Oliveira; GUIMARÃES, Guilherme Veiga; BOCCHI, Edimar Alcides
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.13%
BACKGROUND: The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients either on non-optimized or off beta-blocker therapy is known to be unreliable. The aim of this study was to evaluate the relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients receiving optimized and non-optimized beta-blocker treatment during a treadmill cardiopulmonary exercise test. METHODS: A total of 27 sedentary heart failure patients (86% male, 50±12 years) on optimized beta-blocker therapy with a left ventricle ejection fraction of 33±8% and 35 sedentary non-optimized heart failure patients (75% male, 47±10 years) with a left ventricle ejection fraction of 30±10% underwent the treadmill cardiopulmonary exercise test (Naughton protocol). Resting and peak effort values of both the percentage of oxygen consumption reserve and percentage of heart rate reserve were, by definition, 0 and 100, respectively. RESULTS: The heart rate slope for the non-optimized group was derived from the points 0.949±0.088 (0 intercept) and 1.055±0.128 (1 intercept), p<0.0001. The heart rate slope for the optimized group was derived from the points 1.026±0.108 (0 intercept) and 1.012±0.108 (1 intercept)...

Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients

CARVALHO, Vitor Oliveira; GUIMARÃES, Guilherme Veiga; CIOLAC, Emmanuel Gomes; BOCCHI, Edimar Alcides
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.17%
BACKGROUND: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS: Twenty-five heart failure patients (49±11 years, 76% male), with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS: Basal heart rate was lower in heart failure patients (57±3 bpm) compared to controls (89±14 bpm; p<0.0001). Similarly, the peak heart rate (% maximum predicted for age) was lower in HF patients (65.4±11.1%) compared to controls (98.6±2.2; p<0.0001). Maximum respiratory exchange ratio did not differ between the groups (1.2±0.5 for controls and 1.15±1 for heart failure patients; p=0.42). All controls reached the maximum heart rate for their age...

Recuperação da freqüência cardíaca após teste de esforço em esteira ergométrica e variabilidade da freqüência cardíaca em 24 horas em indivíduos sadios; Heart rate recovery after treadmill electrocardiographic exercise stress test and 24-hour heart rate variability in healthy individuals

ANTELMI, Ivana; CHUANG, Eliseu Yung; GRUPI, Cesar José; LATORRE, Maria do Rosário Dias de Oliveira; MANSUR, Alfredo José
Fonte: Sociedade Brasileira de Cardiologia - SBC Publicador: Sociedade Brasileira de Cardiologia - SBC
Tipo: Artigo de Revista Científica
POR
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66.15%
FUNDAMENTO: A recuperação da freqüência cardíaca após o eletrocardiograma de esforço em esteira ergométrica é modulada pelo sistema nervoso autônomo. A análise da variabilidade da freqüência cardíaca (VFC) pode fornecer informações valiosas sobre o controle do sistema nervoso autônomo sobre o sistema cardiovascular. OBJETIVO: O objetivo deste estudo foi testar a hipótese de associação entre a recuperação da freqüência cardíaca após teste de esforço em esteira ergométrica e a variabilidade da freqüência cardíaca. MÉTODOS: Foram estudamos 485 indivíduos sem evidência de cardiopatia com média de idade de 42± 12,1 (faixa etária de 15 a 82) anos, 281 (57.9%) dos quais do sexo feminino, submetidos a um teste de esforço em esteira ergométrica e avaliação da VFC nos domínios do tempo (SDNN, SDANN, SDNNi, rMSSD e pNN50) e da freqüência (LF, HF, VLF e razão LF/HF) durante monitoramento eletrocardiográfico ambulatorial de 24 horas. RESULTADOS: A recuperação da freqüência cardíaca foi de 30 ± 12 batimentos no 1º minuto e 52± 13 batimentos no 2º minuto após o exercício. Os indivíduos mais jovens de recuperaram mais rápido do 2º ao 5º minuto após o exercício (r = 0,19-0,35, P < 0,05). As mulheres se recuperaram mais rápido que os homens (4 ± 1...

Estudo das alterações da variabilidade da freqüência cardíaca e troponina no paciente séptico; Heart rate variability and troponin in septic patients

Nogueira, Antonio Carlos
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 24/04/2006 PT
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66.13%
CONTEXTO: Estudos observacionais têm demonstrado alterações na variabilidade da freqüência cardíaca em pacientes em sepse, embora não exista publicação correlacionando lesão cardíaca causada pela inflamação sistêmica e redução da variabilidade da freqüência cardíaca. OBJETIVOS: Determinar, em pacientes em sepse, se a lesão cardíaca é causa das alterações da variabilidade da freqüência cardíaca e sua correlação com a mortalidade. Analisar também a associação entre evolução clínica e variabilidade da freqüência cardíaca, troponina, lesão celular à microscopia eletrônica e óptica e variáveis hemodinâmicas. MÉTODO: Estudo observacional, prospectivo, entre pacientes que desenvolveram sepse grave ou choque séptico, analisando sobrevida. Foram analisados: variabilidade da freqüência cardíca (alta e baixa freqüência, através da monitorização cardíaca contínua), dosagem dos níveis séricos de troponina, creatinofosfoquinase e creatinofosfoquinase fração MB, proteína C-reativa, alterações morfológicas e funcionais das células cardíacas por microscopia óptica e eletrônica e imunoistoquímica. Os dados hemodinâmicos foram obtidos por ecocardiograma e medida direta por cateter de artéria pulmonar. RESULTADOS: Dos 31 pacientes incluídos...

Influência da idade e do sexo na frequência cardíaca, nas arritmias cardíacas e nos distúrbios da condução atrioventricular em indivíduos assintomáticos sem evidência de doença cardíaca; Influence of age and sex on heart rate, cardiac arrhythmias and atrioventricular conduction disturbances in asymptomatic individuals without evidence of heart disease

Paula, Rogério Silva de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/11/2002 PT
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66.16%
Há escassos estudos sobre a monitorização eletrocardiográfica ambulatorial em casuísticas brasileiras de indivíduos assintomáticos submetidos ao exame clínico. Com a finalidade de avaliar a freqüência cardíaca, as arritmias cardíacas, e os distúrbios atrioventriculares de condução, foram estudados 625 indivíduos assintomáticos, com exame clínico normal. A idade variou de 15 a 83 (média 42, desvio padrão 11,9) anos; 276 (44,2%) eram homens e 349 (55,8%) mulheres. Os indivíduos foram submetidos ao exame clínico, que incluiu história, exame físico e avaliação laboratorial, além da monitorização eletrocardiográfica ambulatorial de 24 h. Foram estudadas as variáveis obtidas na monitorização eletrocardiográfica ambulatorial nas 24 h de gravação e nos períodos das 6h às 22h, e das 22h às 6h em relação às variáveis do exame clínico-laboratorial. Para a análise dos dados, depois da estatística descritiva, as variáveis contínuas foram examinadas com o emprego da correlação canônica, da regressão linear simples e da regressão linear múltipla. As variáveis categóricas foram analisadas por meio da regressão logística. A freqüência cardíaca mínima nas 24h e no período das 22h às 6h elevou-se com o aumento da idade apenas nos homens. A idade foi a principal influência nas variáveis de freqüência cardíaca na correlação canônica (0...

Autonomic control of heart rate during forced activity and digestion in the snake Boa constrictor

Wang, T.; Taylor, E. W.; Andrade, D.; Abe, Augusto Shinya
Fonte: Company of Biologists Ltd Publicador: Company of Biologists Ltd
Tipo: Artigo de Revista Científica Formato: 3553-3560
ENG
Relevância na Pesquisa
66.12%
Reptiles, particularly snakes, exhibit large and quantitatively similar increments in metabolic rate during muscular exercise and following a meal, when they are apparently inactive. The cardiovascular responses are similar during these two states, but the underlying autonomic control of the heart remains unknown. We describe both adrenergic and cholinergic tonus on the heart during rest, during enforced activity and during digestion (24-36h after ingestion of 30% of their body mass) in the snake Boa constrictor. The snakes were equipped with an arterial catheter for measurements of blood pressure and heart rate, and autonomic tonus was determined following infusion of the beta -adrenergic antagonist propranolol (3mg kg(-1)) and the muscarinic cholinoceptor antagonist atropine (3 mg kg-1).The mean heart rate of fasting animals at rest was 26.4 +/- 1.4 min(-1), and this increased to 36.1 +/- 1.4 min(-1) (means +/- S.E.M.; N=8) following double autonomic block (atropine and propranolol). The calculated cholinergic and adrenergic tones were 60.1 +/- 0.3% and 19.8 +/- 2.2%, respectively. Heart rate increased to 61.4 +/- 1.5 min(-1) during enforced activity, and this response was significantly reduced by propranolol (maximum values of 35.8 +/-1.6 min(-1))...

Resting heart rate: Its correlations and potential for screening metabolic dysfunctions in adolescents

Fernandes, Rômulo A.; Vaz Ronque, Enio R.; Venturini, Danielle; Barbosa, Décio S.; Silva, Danilo P.; Cogo, Crisieli T.; Carnelossi, Mariana Souza; Batista, Mariana B.; Coelho-e-Silva, Manuel J.; Sardinha, Luís B.; Cyrino, Edilson S.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.11%
Background: In pediatric populations, the use of resting heart rate as a health index remains unclear, mainly in epidemiological settings. The aims of this study were to analyze the impact of resting heart rate on screening dyslipidemia and high blood glucose and also to identify its significance in pediatric populations.Methods: The sample was composed of 971 randomly selected adolescents aged 11 to 17 years (410 boys and 561 girls). Resting heart rate was measured with oscillometric devices using two types of cuffs according to the arm circumference. Biochemical parameters triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and glucose were measured. Body fatness, sleep, smoking, alcohol consumption and cardiorespiratory fitness were analyzed.Results: Resting heart rate was positively related to higher sleep quality (β = 0.005, p = 0.039) and negatively related to cardiorespiratory fitness (β = -0.207, p = 0.001). The receiver operating characteristic curve indicated significant potential for resting heart rate in the screening of adolescents at increased values of fasting glucose (area under curve = 0.611 ± 0.039 [0.534 - 0.688]) and triglycerides (area under curve = 0.618 ± 0.044 [0.531 - 0.705]).Conclusion: High resting heart rate constitutes a significant and independent risk related to dyslipidemia and high blood glucose in pediatric populations. Sleep and cardiorespiratory fitness are two important determinants of the resting heart rate. © 2013 Fernandes et al.; licensee BioMed Central Ltd.

Heart rate recovery after exercise: relations to heart rate variability and complexity

Javorka,M.; Zila,I.; Balhárek,T.; Javorka,K.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2002 EN
Relevância na Pesquisa
66.12%
Physical exercise is associated with parasympathetic withdrawal and increased sympathetic activity resulting in heart rate increase. The rate of post-exercise cardiodeceleration is used as an index of cardiac vagal reactivation. Analysis of heart rate variability (HRV) and complexity can provide useful information about autonomic control of the cardiovascular system. The aim of the present study was to ascertain the association between heart rate decrease after exercise and HRV parameters. Heart rate was monitored in 17 healthy male subjects (mean age: 20 years) during the pre-exercise phase (25 min supine, 5 min standing), during exercise (8 min of the step test with an ascending frequency corresponding to 70% of individual maximal power output) and during the recovery phase (30 min supine). HRV analysis in the time and frequency domains and evaluation of a newly developed complexity measure - sample entropy - were performed on selected segments of heart rate time series. During recovery, heart rate decreased gradually but did not attain pre-exercise values within 30 min after exercise. On the other hand, HRV gradually increased, but did not regain rest values during the study period. Heart rate complexity was slightly reduced after exercise and attained rest values after 30-min recovery. The rate of cardiodeceleration did not correlate with pre-exercise HRV parameters...

Role of the cardiac nerve in the effect of a novel innocuous stimulus on the heart rate of Megalobulimus mogianensis

Romero,S.M.B.; Hoffmann,A.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2006 EN
Relevância na Pesquisa
66.11%
The effects of a brief jet of water delivered to the anterior portion of body-head on the heart rate of Megalobulimus mogianensis were determined in a group of intact snails (N = 8), previously prepared for electrocardiogram recording. The heart rate was significantly increased following stimulation. Nevertheless, with repetition of the stimulus there was a significant decrease in the magnitude of the heart rate variation and in the time for the basal heart rate to recover (first stimulus, 7.4 ± 1.2 bpm and 15.5 ± 1.8 min; second stimulus, 4.8 ± 1.0 bpm and 10.6 ± 1.5 min; third stimulus, 5.0 ± 0.3 bpm and 11.1 ± 1.8 min), indicating that this behavioral response undergoes early habituation. To determine the role of the cardiac nerve in mediating the heart rate alterations induced by the jet of water two other groups were tested: denervated animals (N = 8) and sham-operated control animals (N = 8). Although the innocuous stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (3.2 ± 0.4 bpm) was 41% of the value obtained in sham-operated animals (7.8 ± 1.5 bpm), indicating that the cardiac nerve is responsible for 59% of the cardioacceleration induced by the innocuous stimulus. The increase in heart rate observed in denervated animals may be due to an increase in venous return promoted by the intense muscular activity associated with the retraction-protraction of the anterior part of the body induced by the jet of water.

Role of the cardiac nerve in the adaptive changes of heart rate in response to an aversive stimulus in Megalobulimus mogianensis

Romero,S.M.B.; Hoffmann,A.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2008 EN
Relevância na Pesquisa
66.13%
The effect of an aversive stimulus represented by contact with a hot plate on the heart rate of Megalobulimus mogianensis was evaluated with electrocardiogram recording in intact snails (N = 8). All stimulated animals showed an increase in heart rate, with mean values ranging from 35.6 ± 1.2 (basal heart rate) to 43.8 ± 0.9 bpm (post-stimulation heart rate). The cardioacceleration was followed by gradual recovery of the basal heart rate, with mean recovery times varying from 4.3 ± 0.3 to 5.8 ± 0.6 min. Repetition of the stimulus did not affect the magnitude of variation nor did it influence the basal heart rate recovery time. To investigate the role of the cardiac nerve in mediating the heart rate alterations induced by the aversive stimulus, denervated (N = 8) and sham-operated (N = 8) animals were also tested. Although the aversive stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (4.4 ± 0.4 bpm) was 57% of the value obtained in sham-operated animals (7.7 ± 1.3 bpm), indicating that the cardiac nerve is responsible for 43% of the cardioacceleration induced by the aversive stimulus. The cardioacceleration observed in denervated snails may be due to an increase in venous return promoted by the intense muscular activity associated with the withdrawal response. Humoral factors may also be involved. A probable delaying inhibitory effect of the cardiac nerve on the recuperation of the basal heart rate is suggested.

Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients

Carvalho,Vitor Oliveira; Guimarães,Guilherme Veiga; Ciolac,Emmanuel Gomes; Bocchi,Edimar Alcides
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
66.17%
BACKGROUND: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS: Twenty-five heart failure patients (49±11 years, 76% male), with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS: Basal heart rate was lower in heart failure patients (57±3 bpm) compared to controls (89±14 bpm; p<0.0001). Similarly, the peak heart rate (% maximum predicted for age) was lower in HF patients (65.4±11.1%) compared to controls (98.6±2.2; p<0.0001). Maximum respiratory exchange ratio did not differ between the groups (1.2±0.5 for controls and 1.15±1 for heart failure patients; p=0.42). All controls reached the maximum heart rate for their age...

The relationship between heart rate reserve and oxygen uptake reserve in heart failure patients on optimized and non-optimized beta-blocker therapy

Carvalho,Vitor Oliveira; Guimarães,Guilherme Veiga; Bocchi,Edimar Alcides
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
66.13%
BACKGROUND: The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients either on non-optimized or off beta-blocker therapy is known to be unreliable. The aim of this study was to evaluate the relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients receiving optimized and non-optimized beta-blocker treatment during a treadmill cardiopulmonary exercise test. METHODS: A total of 27 sedentary heart failure patients (86% male, 50±12 years) on optimized beta-blocker therapy with a left ventricle ejection fraction of 33±8% and 35 sedentary non-optimized heart failure patients (75% male, 47±10 years) with a left ventricle ejection fraction of 30±10% underwent the treadmill cardiopulmonary exercise test (Naughton protocol). Resting and peak effort values of both the percentage of oxygen consumption reserve and percentage of heart rate reserve were, by definition, 0 and 100, respectively. RESULTS: The heart rate slope for the non-optimized group was derived from the points 0.949±0.088 (0 intercept) and 1.055±0.128 (1 intercept), p<0.0001. The heart rate slope for the optimized group was derived from the points 1.026±0.108 (0 intercept) and 1.012±0.108 (1 intercept)...

Heart Rate at Hospital Discharge in Patients With Heart Failure Is Associated With Mortality and Rehospitalization

Laskey, Warren K.; Alomari, Ihab; Cox, Margueritte; Schulte, Phillip J.; Zhao, Xin; Hernandez, Adrian F.; Heidenreich, Paul A.; Eapen, Zubin J.; Yancy, Clyde; Bhatt, Deepak L.; Fonarow, Gregg C.
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
66.12%
Background: Whether heart rate upon discharge following hospitalization for heart failure is associated with long‐term adverse outcomes and whether this association differs between patients with sinus rhythm (SR) and atrial fibrillation (AF) have not been well studied. Methods and Results: We conducted a retrospective cohort study from clinical registry data linked to Medicare claims for 46 217 patients participating in Get With The Guidelines®–Heart Failure. Cox proportional‐hazards models were used to estimate the association between discharge heart rate and all‐cause mortality, all‐cause readmission, and the composite outcome of mortality/readmission through 1 year. For SR and AF patients with heart rate ≥75, the association between heart rate and mortality (expressed as hazard ratio [HR] per 10 beats‐per‐minute increment) was significant at 0 to 30 days (SR: HR 1.30, 95% CI 1.22 to 1.39; AF: HR 1.23, 95% CI 1.16 to 1.29) and 31 to 365 days (SR: HR 1.15, 95% CI 1.12 to 1.20; AF: HR 1.05, 95% CI 1.01 to 1.08). Similar associations between heart rate and all‐cause readmission and the composite outcome were obtained for SR and AF patients from 0 to 30 days but only in the composite outcome for SR patients over the longer term. The HR from 0 to 30 days exceeded that from 31 to 365 days for both SR and AF patients. At heart rates <75...

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 EN
Relevância na Pesquisa
66.11%
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)...

Untersuchung der Herzfrequenzvariabilität bei Jugendlichen mit Psychotischer Störung; Heart Rate Variability in Adolescents With Psychosis

Mayer, Melanie
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
66.11%
Thema: In dieser Studie wurde der Einfluss des vegetativen Nervensystems von Jugendlichen mit Psychose im Vergleich zu einer Kontrollgruppe mit Diagnosen aus dem gesamten Jugendpsychiatrischen Kollektiv anhand der Herzfrequenzvariabilität untersucht. Methode: In unserer retrospektiven Studie sind 36 Patienten mit Psychose und 123 andere Patienten der Kinder- und Jugendpsychiatrie Tübingen im Alter von 15 bis 18 Jahren sowie zwei Probanden im Alter von 19 und 20 vertreten. Die Analyse der Parameter erfolgte an einem 256 Sekunden dauernden Abschnitt einer halbstandardisierten digitalen EKG-Aufzeichnung. Dazu wurden die Herzfrequenz, die Parameter pNN00 bis pNN90, die parasympathischen Marker SDRR, RMSSD, CV, HF, MF, SD1 und SD2 sowie die sympathischen Werte LF und LF/HF-Ratio bestimmt. Als umfassendes Maß für die autonome Erregung ermöglicht die HRV eine Differenzierung in Sympathikus und Parasympathikus. Zusammenfassung: Insgesamt zeigte sich eine Verminderung der HRV bei Jugendlichen mit Psychose - gezeigt durch eine verringerte Aktivität des Parasympathikus (signifikante Unterschiede bei SDRR und CV zwischen der Fall- und Kontrollgruppe) sowie eine tendenziell erhöhte Aktivität des Sympathikus, die durch die Differenz der LFPowsum nachweisbar war. Außerdem war eine erhöhte Herzfrequenz bei Jugendlichen mit Psychose nachweisbar. Bei einer Aufteilung auf die verschiedenen medikamentösen Therapien zeigte sich ein verstärkter Sympathikus-Einfluss bei Patienten mit klassischer Antipsychotika-Therapie in der Fallgruppe. Dies zeigte sich durch eine erhöhte Herzfrequenz und erhöhte Werte der Lowfrequency. Für eine Verminderung des Parasympathikus-Einflusses sprechen die niedrigeren Werte von SD1 und SD2. Bei den Probanden mit atypischer Neuroleptika-Therapie zeigte sich lediglich die Herzfrequenz erniedrigt. Bei der Unterscheidung zwischen den Geschlechtern zeigte sich eine erhöhte Aktivierung des autonomen Nervensystems – sowohl des sympathischen als auch des parasympathischen Anteils - bei Jungen mit Überwiegen des Parasympathikus...

Klinische Machbarkeitsstudie: Messung der maternalen Herzfrequenz durch einen in den Tokografie-Transducer integrierten Infrarot-Sensor im Rahmen der Kardiotokografie; Clinical feasibility study: measurement of maternal heart rate by an infrared sensor built into the tocography transducer in the context of cardiotocography

Dongus, Kathrin Verena
Fonte: Universität Tübingen Publicador: Universität Tübingen
Tipo: Dissertation; info:eu-repo/semantics/doctoralThesis
DE_DE
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66.16%
Einführung: In der Geburtshilfe gehört die Überwachung des Fetus mit Hilfe des CTGs heutzutage zu einem akzeptablen Standard. Am häufigsten wird dabei die fetale Herzfrequenz mit einem Doppler-Ultraschall-Transducer detektiert (Ultrasonokardiografie). In einigen Fällen wird jedoch statt der kindlichen Herzfrequenz ein mütterliches Signal abgeleitet. Liegt die maternale Herzfrequenz in einem für den Fetus normalen Frequenzbereich (um 130 bpm), kann es im schlimmsten Fall dazu kommen, dass die falsche Messung nicht erkannt wird und die aufgezeichnete Herzfrequenz falsch interpretiert wird. Ein asphyktisches Neugeborenes oder eine Totgeburt sind die schlimmsten Folgen dieses vermeidbaren Fehlers. Denn falls zusätzlich eine maternale Herzfrequenz abgeleitet wird (z. B. durch das Verfahren der Pulsoxymetrie oder mittels Ableitung eines maternalen EKGs), kann die Übereinstimmung der zwei Herzfrequenzen erkannt und der Anwender alarmiert werden (sogenannte Koinzidenzerkennung). Meist wird jedoch auf die kontinuierliche Überwachung der mütterlichen Herzfrequenz aus Gründen des Patientinnenkomforts verzichtet. Material und Methodik: In dieser Studie wurde eine neue Möglichkeit der Koinzidenzerkennung untersucht. Die mütterliche Herzfrequenz wurde mit einem modifizierten Tokografie-Transducer („Bauchpulssensor“) gemessen. Der Vorteil dieses Prinzips beruht auf der Integration einer mütterlichen Herzfrequenzmessung in den sowieso beim CTG angelegten Tokografie-Transducer. So kann die Koinzidenzanalyse immer arbeiten...

A Multisite Study of Initial Respiration Rate and Heart Rate as Predictors of Posttraumatic Stress Disorder

Bryant, R.; Creamer, M.; O'Donnell, M.; Silove, D.; McFarlane, A.
Fonte: Physicians Postgraduate Press Publicador: Physicians Postgraduate Press
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
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OBJECTIVE: Fear-conditioning models posit that increased arousal at the time of trauma predicts subsequent posttraumatic stress disorder (PTSD). This multisite study evaluated the extent to which acute heart rate and respiration rate predict subsequent chronic PTSD. METHOD: Traumatically injured patients admitted to 4 hospitals across Australia between April 2004 and February 2006 were initially assessed during hospital admission (N = 1105) and were reassessed 3 months later for PTSD by using the Clinician-Administered PTSD Scale-IV and for major depressive disorder (MDD) by using the Mini-International Neuropsychiatric Interview (English version 5.0.0) (N = 955). Heart rate, respiration rate, and blood pressure were assessed on the initial day of traumatic injury. RESULTS: Ninety patients (10%) met criteria for PTSD and 159 patients (17%) met criteria for MDD at the 3-month assessment. Patients with PTSD compared to those without PTSD had higher heart rate (90.16 +/- 18.66 vs. 84.84 +/-17.41, t = 2.74, p < .01) and respiration rate (20.24 +/- 5.16 vs. 18.58 +/- 4.29, t = 3.43, p < .001) immediately after injury. There were no heart rate or respiration rate differences between patients who did and did not develop MDD. Patients were more likely to develop PTSD at 3 months if they had a heart rate of at least 96 beats per minute (15% vs. 8%...

Heart Rate Balancing for Multiplayer Exergames

STACH, TADEUSZ BENEDICT
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
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Exergames combine physical activity and entertainment in an effort to increase people’s motivation to exercise. Multiplayer exergames attempt to include the motivating aspects of group activity by allowing two or more people to play together. In most multiplayer exergames, a player’s in-game performance is limited by her physical abilities. Less fit players are demotivated by repeated losses to more fit opponents, while fitter players face a lack of competition from unfit opponents. This situation makes it difficult for people of disparate physical abilities to play exergames together. This research presents heart rate balancing, a novel player balancing technique to better support engaging experiences in multiplayer exergames. Heart rate balancing bases players’ in-game performance on their effort relative to fitness level rather than their raw power. More specifically, heart rate monitoring is used to set in-game performance based on how closely a person adheres to her target heart rate. Experiments with heart rate balancing show that the technique improves competition between players. A strong correlation was found between people’s perceived effort and their in-game performance with heart rate balancing. The degree to which players noticed the balancing mechanism varied depending on game type. However...

Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients

Carvalho, Vitor Oliveira; Guimarães, Guilherme Veiga; Ciolac, Emmanuel Gomes; Bocchi, Edimar Alcides
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 01/01/2008 ENG
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BACKGROUND: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS: Twenty-five heart failure patients (49±11 years, 76% male), with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS: Basal heart rate was lower in heart failure patients (57±3 bpm) compared to controls (89±14 bpm; p