|
|
|
| Registros recuperados: 28 | |
|
| |
|
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
| |
|
|
| 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 |
| |
|
|
| Dourado,V.Z.; Guerra,R.L.F.. |
| Studies on the assessment of heart rate variability threshold (HRVT) during walking are scarce. We determined the reliability and validity of HRVT assessment during the incremental shuttle walk test (ISWT) in healthy subjects. Thirty-one participants aged 57 ± 9 years (17 females) performed 3 ISWTs. During the 1st and 2nd ISWTs, instantaneous heart rate variability was calculated every 30 s and HRVT was measured. Walking velocity at HRVT in these tests (WV-HRVT1 and WV-HRVT2) was registered. During the 3rd ISWT, physiological responses were assessed. The ventilatory equivalents were used to determine ventilatory threshold (VT) and the WV at VT (WV-VT) was recorded. The difference between WV-HRVT1 and WV-HRVT2 was not statistically significant (median and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heart rate variability; Exercise; Walking; Adults. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2013000200194 |
| |
|
| |
|
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
| |
|
|
| 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 |
| |
|
|
| de Miranda,É.J.F. Peixoto; Hoshi,R.A.; Bittencourt,M.S.; Goulart,A.C.; Santos,I.S.; Brunoni,A.R.; Diniz,M.F.H.S.; Ribeiro,A.L.P.; Dantas,E.M.; Mill,J.G.; Lotufo,P.A.; Benseñor,I.M.. |
| The association between subclinical thyroid dysfunctions and autonomic modulation changes has been described by many studies with conflicting results. We aimed to analyze the association between subclinical hyperthyroidism (SCHyper), subclinical hypothyroidism (SCHypo), and heart rate variability (HRV) using the baseline from ELSA-Brasil. SCHyper and SCHypo were classified by use of medication to treat thyroid disorders, thyrotropin levels respectively above and under the reference range, and normal free thyroxine levels. For HRV, the participants underwent 10 min in supine position and the R-R intervals of the final 5 min were selected for analysis. We first used linear regression models to report crude data and then, multivariate adjustment for... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Subclinical hypothyroidism; Subclinical hyperthyroidism; Heart rate variability; Autonomic nervous system. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2018001100601 |
| |
|
|
| Schaan,B.D.; Dall'Ago,P.; Maeda,C.Y.; Ferlin,E.; Fernandes,T.G.; Schmid,H.; Irigoyen,M.C.. |
| Streptozotocin (STZ)-induced diabetes in rats is characterized by cardiovascular dysfunction beginning 5 days after STZ injection, which may reflect functional or structural autonomic nervous system damage. We investigated cardiovascular and autonomic function, in rats weighing 166 ± 4 g, 5-7, 14, 30, 45, and 90 days after STZ injection (N = 24, 33, 27, 14, and 13, respectively). Arterial pressure (AP), mean AP (MAP) variability (standard deviation of the mean of MAP, SDMMAP), heart rate (HR), HR variability (standard deviation of the normal pulse intervals, SDNN), and root mean square of successive difference of pulse intervals (RMSSD) were measured. STZ induced increased glycemia in diabetic rats vs control rats. Diabetes reduced resting HR from 363 ± 12... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diabetes; Streptozotocin; Heart rate variability; Rats; Autonomic nervous system; Arterial pressure variability. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004001200016 |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
| |
|
| |
| Registros recuperados: 28 | |
|
|
|
