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| Registros recuperados: 28 | |
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| Walther,T.; Wessel,N.; Kang,N.; Sander,A.; Tschöpe,C.; Malberg,H.; Bader,M.; Voss,A.. |
| Heart rate variability is a relevant predictor of cardiovascular risk in humans. A significant genetic influence on heart rate variability is suggested, although the genes involved are ill-defined. The Mas-protooncogene encodes a G-protein-coupled receptor with seven transmembrane domains highly expressed in testis and brain. Since this receptor is supposed to interact with the signaling of angiotensin II, which is an important regulator of cardiovascular homeostasis, heart rate and blood pressure were analyzed in Mas-deficient mice. Using a femoral catheter the blood pressure of mice was measured for a period of 30 min and 250 data values per second were recorded. The mean values and range of heart rate and blood pressure were then calculated. Neither... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Blood pressure variability; Heart rate variability; Baroreflex sensitivity; Mas protooncogene. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000000100001 |
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| Natali,J.E.S.; Santos,B.T.; Rodrigues,V.H.; Chauí-Berlinck,J.G.. |
| In anurans, changes in ambient temperature influence body temperature and, therefore, energy consumption. These changes ultimately affect energy supply and, consequently, heart rate (HR). Typically, anurans living in different thermal environments have different thermal sensitivities, and these cannot be distinguished by changes in HR. We hypothesized that Rhinella jimi (a toad from a xeric environment that lives in a wide range of temperatures) would have a lower thermal sensitivity regarding cardiac control than R. icterica (originally from a tropical forest environment with a more restricted range of ambient temperatures). Thermal sensitivity was assessed by comparing animals housed at 15° and 25°C. Cardiac control was estimated by heart rate... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Anuran; Cardiac control; Heart rate complexity; Heart rate variability; Thermal physiology. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2015000100046 |
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| Quevedo,D.A.C.; Lourenço,M.L.G.; Bolaños,C.A.D.; Takahira,R.K.; Oba,E.; Alfonso,A.; Chiacchio,S.B.. |
| ABSTRACT This study aims at evaluating the effects of electrolytes, glucose and cortisol levels over heart rate (HR) and heart rate variability (HRV) in healthy newborn calves. Seventeen healthy Holstein calves were evaluated during their first month of life, and the plasma concentrations of glucose, cortisol, calcium, magnesium, inorganic phosphorus, sodium and potassium were analyzed. HRV indexes were determined in the time and frequency domains through the analysis of neonatal electrocardiogram recordings. In the first day, low blood levels of phosphorus presented a strong correlation with the HR and the increased high-frequency components of HRV. The plasma concentrations of magnesium decreased significantly throughout the 35 days, revealing a positive... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calves; Electrolytes; Glucose; Cortisol; Heart rate variability. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352019000601922 |
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| Neves,V.F.C.; Silva de Sá,M.F.; Gallo Jr.,L.; Catai,A.M.; Martins,L.E.B.; Crescêncio,J.C.; Perpétuo,N.M.; Silva,E.. |
| The aim of the present study was to determine whether estrogen therapy (ET) reduces alterations of the autonomic control of heart rate (HR) due to hypoestrogenism and aging. Thirteen young (24 ± 2.6 years), 10 postmenopausal (53 ± 4.6 years) undergoing ET (PM-ET), and 14 postmenopausal (56 ± 2.6 years) women not undergoing ET (PM) were studied. ET consisted of 0.625 mg/day conjugated equine estrogen. HR was recorded continuously for 8 min at rest in the supine and sitting positions. HR variability (HRV) was analyzed by time (SDNN and rMSSD indices) and frequency domain methods. Power spectral components are reported as normalized units (nu) at low (LF) and high (HF) frequencies, and as LF/HF ratio. Intergroup comparisons: SDNN index was higher in young... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heart rate variability; Aging; Menopause; Estrogen therapy. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2007000400007 |
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| Machado,H.G.; Simões,R.P.; Mendes,R.G.; Castello,V.; Di Thommazo,L.; Almeida,L.B.; Lopes,S.L.B.; Catai,A.M.; Borghi-Silva,A.. |
| The purpose of this study was to investigate the behavior of heart rate (HR) and HR variability (HRV) during different loads of resistance exercise (incline bench press) in patients with coronary artery disease (CAD) and healthy sedentary controls. Ten healthy men (65 ± 1.2 years, control group, CG) and 10 men with clinically stable CAD (66 ± 2.4 years, CADG) were recruited. A discontinuous progressive protocol was applied with an initial load of 10% of the maximum load achieved in the 1RM (1 repetition maximum) with increases of 10% until 30% 1RM was reached, which was followed by subsequent increases of 5% 1RM until exhaustion. HRV was analyzed by linear and non-linear methods. There was a significant reduction in rMSSD (CG: 20 ± 2 to 11 ± 3 ms; CADG: 19... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dynamic resistance exercise; Coronary artery disease; Heart rate variability; Autonomic nervous system; Upper limb exercise. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011001200012 |
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| Cruz,R.K.S.; Alfonso,A.; Lourenço,M.L.G.; Souza,F.F.; Oba,E.; Ramos,P.R.R.; Chiacchio,S.B.. |
| ABSTRACT The aim of this study was to evaluate newborn foals stress in the first 48 hours of life. Heart rate (HR), heart rate variability (HRV) and serum cortisol concentrations, blood glucose, and lactate were determined in foals (n = 20, Paint Horse). Cortisol concentrations decreased significantly between four and 48 hours, with the highest concentration at 4 hours after birth. Positive correlations between cortisol and lactate occurred between 12 and 16 hours. And there was a negative correlation between cortisol and lactate 4 hours after birth. Among the values obtained for HR, there was significantly difference between the the value obtained at twelve hours of life moment and all the other moments measured, the highest values were at birth, 24 and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equine neonate; Cortisol; Heart rate; Heart rate variability. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352017000400785 |
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| Catai,A.M.; Chacon-Mikahil,M.P.T.; Martinelli,F.S.; Forti,V.A.M.; Silva,E.; Golfetti,R.; Martins,L.E.B.; Szrajer,J.S.; Wanderley,J.S.; Lima-Filho,E.C.; Milan,L.A.; Marin-Neto,J.A.; Maciel,B.C.; Gallo-Junior,L.. |
| The purpose of the present study was to evaluate the effects of aerobic physical training (APT) on heart rate variability (HRV) and cardiorespiratory responses at peak condition and ventilatory anaerobic threshold. Ten young (Y: median = 21 years) and seven middle-aged (MA = 53 years) healthy sedentary men were studied. Dynamic exercise tests were performed on a cycloergometer using a continuous ramp protocol (12 to 20 W/min) until exhaustion. A dynamic 24-h electrocardiogram was analyzed by time (TD) (standard deviation of mean R-R intervals) and frequency domain (FD) methods. The power spectral components were expressed as absolute (a) and normalized units (nu) at low (LF) and high (HF) frequencies and as the LF/HF ratio. Control (C) condition: HRV in TD... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heart rate variability; Power spectral density analysis; Anaerobic threshold; Aerobic exercise training; Autonomic nervous system and aging processes in man. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000600016 |
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| Melo,R.C.; Santos,M.D.B.; Silva,E.; Quitério,R.J.; Moreno,M.A.; Reis,M.S.; Verzola,I.A.; Oliveira,L.; Martins,L.E.B.; Gallo-Junior,L.; Catai,A.M.. |
| The effects of the aging process and an active life-style on the autonomic control of heart rate (HR) were investigated in nine young sedentary (YS, 23 ± 2.4 years), 16 young active (YA, 22 ± 2.1 years), 8 older sedentary (OS, 63 ± 2.4 years) and 8 older active (OA, 61 ± 1.1 years) healthy men. Electrocardiogram was continuously recorded for 15 min at rest and for 4 min in the deep breathing test, with a breath rate of 5 to 6 cycles/min in the supine position. Resting HR and RR intervals were analyzed by time (RMSSD index) and frequency domain methods. The power spectral components are reported in normalized units (nu) at low (LF) and high (HF) frequency, and as the LF/HF ratio. The deep breathing test was analyzed by the respiratory sinus arrhythmia... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Heart rate variability; Respiratory sinus arrhythmia; Autonomic nervous system; Aging process; Aerobic exercise. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000900007 |
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| Martinelli,F.S.; Chacon-Mikahil,M.P.T.; Martins,L.E.B.; Lima-Filho,E.C.; Golfetti,R.; Paschoal,M.A.; Gallo-Junior,L.. |
| The purpose of the present study was to determine if autonomic heart rate modulation, indicated by heart rate variability (HRV), differs during supine rest and head-up tilt (HUT) when sedentary and endurance-trained cyclists are compared. Eleven sedentary young men (S) and 10 trained cyclists (C) were studied. The volunteers were submitted to a dynamic ECG Holter to calculate HRV at rest and during a 70º HUT. The major aerobic capacity of athletes was expressed by higher values of <img src="/img/revistas/bjmbr/v38n4/Vo.gif">at anaerobic threshold and peak conditions (P < 0.05). At rest the athletes had lower heart rates (P < 0.05) and higher values in the time domain of HRV compared with controls (SD of normal RR interval, SDNN, medians): 59.1... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Endurance; Power spectral analysis; Heart rate variability; Autonomic heart rate modulation; Training bradycardia; Orthostatic stress. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000400019 |
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| Ribeiro,T.F.; Azevedo,G.D.; Crescêncio,J.C.; Marães,V.R.F.S.; Papa,V.; Catai,A.M.; Verzola,R.M.M.; Oliveira,L.; Silva de Sá,M.F.; Gallo Jr.,L.; Silva,E.. |
| The aim of the present study was to compare the modulation of heart rate in a group of postmenopausal women to that of a group of young women under resting conditions on the basis of R-R interval variability. Ten healthy postmenopausal women (mean ± SD, 58.3 ± 6.8 years) and 10 healthy young women (mean ± SD, 21.6 ± 0.82 years) were submitted to a control resting electrocardiogram (ECG) in the supine and sitting positions over a period of 6 min. The ECG was obtained from a one-channel heart monitor at the CM5 lead and processed and stored using an analog to digital converter connected to a microcomputer. R-R intervals were calculated on a beat-to-beat basis from the ECG recording in real time using a signal-processing software. Heart rate variability (HRV)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heart rate variability; Menopause; Autonomic nervous system; Time domain indexes. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000700006 |
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| Kunz,V.C.; Borges,E.N.; Coelho,R.C.; Gubolino,L.A.; Martins,L.E.B.; Silva,E.. |
| The objectives of this study were to evaluate and compare the use of linear and nonlinear methods for analysis of heart rate variability (HRV) in healthy subjects and in patients after acute myocardial infarction (AMI). Heart rate (HR) was recorded for 15 min in the supine position in 10 patients with AMI taking β-blockers (aged 57 ± 9 years) and in 11 healthy subjects (aged 53 ± 4 years). HRV was analyzed in the time domain (RMSSD and RMSM), the frequency domain using low- and high-frequency bands in normalized units (nu; LFnu and HFnu) and the LF/HF ratio and approximate entropy (ApEn) were determined. There was a correlation (P < 0.05) of RMSSD, RMSM, LFnu, HFnu, and the LF/HF ratio index with the ApEn of the AMI group on the 2nd (r = 0.87, 0.65,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Myocardial infarction; Heart rate variability; Autonomic nervous system; Spectral analysis; Nonlinear dynamics. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012000500011 |
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| Pereira-Junior,Pedro P.; Marocolo,Moacir; Rodrigues,Fabricio P.; Medei,Emiliano; Nascimento,José H.M.. |
| Heart rate variability (HRV) analysis consists in a well-established tool for the assessment of cardiac autonomic control, both in humans and in animal models. Conventional methods for HRV analysis in rats rely on conscious state electrocardiogram (ECG) recording based on prior invasive surgical procedures for electrodes/transmitters implants. The aim of the present study was to test a noninvasive and inexpensive method for ECG recording in conscious rats, assessing its feasibility for HRV analysis. A custom-made elastic cotton jacket was developed to fit the rat's mean thoracic circumference, with two pieces of platinum electrodes attached on its inner surface, allowing ECG to be recorded noninvasively in conscious, restrained rats (n=6). Time- and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Electrocardiography; Heart rate variability; Methodology; Noninvasive; Rat. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652010000200019 |
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| Registros recuperados: 28 | |
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