Search Results
Results 601 - 650 of 1786
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Murata Katsuyuki - - 2005
OBJECTIVES: There is evidence that shift work contributes to excess cardiovascular mortality. The purpose of this study was to determine the effects of shift work on heart rate-corrected QT (QTc) and blood pressure in relation to heart rate variability (CV(RR)). METHODS: The study population consisted of 153 male shiftworkers and ...
Cooke William H - - 2005
BACKGROUND: Noninvasive procedures for predicting progression to hemodynamic instability during induced central hypovolemia in humans were evaluated. The purpose of this study was twofold: (1) to track changes in autonomic function induced by a model of hemorrhage, and (2) to determine whether measures of autonomic function are reliable without strict ...
Yoshii Masayoshi - - 2005
Only a little information is available for the evaluation of the complex hemodynamic changes that occur during hemodialysis. Recently, we developed the transthoracic electrical admittance cardiograph for repeated measurements of cardiac output, and monitored hemodynamic changes during hemodialysis by the use of this device. We measured cardiovascular hemodynamic and autonomic ...
Sothern R B - - 2005
Putative circadecadal modulations of a circannual variation in diastolic blood pressure are explored in a still accumulating 35 year record of self-measurements by a clinically healthy man. Analyses of monthly means by gliding spectra, one-way analysis of variance (ANOVA), and cosinor were carried out after removing data collected during travel ...
Pereda Ernesto - - 2005
We made use of multivariate nonlinear analysis methods to study the interdependence between the cardiac interval variability and both the respiratory activity and the systolic pressure in rats. The study was carried out in basal conditions and after the application of different drugs affecting the cardiovascular system. The results showed ...
Madanmohan - - 2005
The purpose of the present study was to determine whether readily measured blood pressure (BP) indices and, responses to autonomic reflex tests could be used as surrogates of short-term heart rate variability (HRV), which is an established marker of autonomic regulation of SA node. Therefore, we examined the correlation between ...
Jhun Hyung-Joon - - 2005
OBJECTIVES: Analysis of heart rate variability (HRV) is useful for measuring cardiovascular autonomic function. The effects of blood metals on cardiovascular autonomic function have not been studied extensively. The objective of the present study was to determine the association between the concentrations of blood metals, including toxic and essential trace ...
McGuire Kimberly M Beckwith - - 2005
We evaluated systolic and diastolic blood pressure, heart rate variability and skin conductance at baseline, and 1 and 4 months in 38 participants with elevated blood pressure, randomly assigned to expressive writing or control groups. There was a significant interaction such that the very low frequency wave of heart rate ...
Goncalvesova E - - 2005
BACKGROUND: Phenylethanolamine N-methyltransferase (PNMT) is an enzyme involved in the epinephrine synthesis. The aim of this study was to investigate PNMT gene expression in the transplanted human heart in relation to the time elapsed from heart transplantation (HTx) and selected clinical characteristics. PATIENTS AND METHODS: The messenger RNA (mRNA) levels ...
Berntson Gary G - - 2005
The root mean square successive difference (RMSSD) in heart period series is a time domain measure of heart period variability. The RMSSD is sensitive to high-frequency heart period fluctuations in the respiratory frequency range and has been used as an index of vagal cardiac control. By transfer function simulations, the ...
Hammer Peter E - - 2005
A mathematical model of the arterial baroreflex was developed and used to assess the stability of the reflex and its potential role in producing the low-frequency arterial blood pressure oscillations called Mayer waves that are commonly seen in humans and animals in response to decreased central blood volume. The model ...
Norton Michele R - - 2005
Fourier-based approaches to analysis of variability of R-R intervals or blood pressure typically compute power in a given frequency band (e.g., 0.01-0.07 Hz) by aggregating the power at each constituent frequency within that band. This paper describes a new approach to the analysis of these data. We propose to partition ...
Sawai Asuka - - 2005
We have developed a wristwatch-type heart rate (HR) recorder (WT-HR tachometer) with an acceleration-pickup sensor, which can record HR and body activity (ACT) minute by minute for a long time (> 120 h). To study its application, we compared these measurements with 24-h blood pressure (BP) and HR variability, sympathovagal ...
Figueroa Arturo - - 2005
The attenuated heart rate (HR) and blood pressure (BP) response to exercise in individuals with Down syndrome (DS) has been attributed to autonomic dysfunction, which has been associated with obesity. Our purpose was to determine the role of autonomic control of HR to the attenuated chronotropic response observed in individuals ...
Okano Yasuko - - 2005
Increased resting heart rate (HR) and increased sympathetic nervous activity are independent risk factors for cardiovascular disease. Recently, base heart rate (HRo: minimum stable HR during sleep) has been reported to relate to cardiac stroke volume and age. However, little is known about the relevance of HRo. The aim of ...
Gao Sinsia A - - 2005
Spontaneous baroreflex sensitivity (BRS), the reflex heart rate modulation in response to blood pressure changes (predominantly an index of cardiac vagal activity) and temporal QT variability (an index of myocardial repolarization) have been demonstrated to convey important prognostic information. The information about reproducibility of BRS and temporal QT variability is ...
Højgaard Michael V - - 2005
OBJECTIVE: Previous studies have indicated moderate-to-poor reproducibility of heart rate variability (HRV) but the reproducibility of blood pressure variability (BPV) and spectral measures of baroreceptor sensitivity (BRS) are not well established. METHODS: We measured normal-to-normal heart beat (RR) interval and finger blood pressure (Finapres) in 14 healthy individuals on three ...
Sanya E O - - 2005
OBJECTIVES: The aim of this study was to assess baroreflex regulation of the heart rate and blood vessels in migraine patients in comparison with healthy controls. METHODS: In 30 migraine patients who were in a headache-free phase, aged 34 +/- 2 years, and 30 healthy controls, aged 34 +/- 3 ...
Hidaka Syozo - - 2005
STUDY OBJECTIVE: To investigate the effect of propofol and midazolam on cardiac autonomic nervous system (CANS) activity during combined spinal-epidural anesthesia. DESIGN: Prospective, clinical study. SETTING: Operating room of a university hospital. PATIENTS: Forty ASA physical status I and II patients scheduled for knee surgery. INTERVENTION: Patients were randomized to ...
Gross Volkmar - - 2005
Regulator of G protein signaling (RGS2) deletion in mice prolongs signaling by G protein-coupled vasoconstrictor receptors and increases blood pressure. However, the exact mechanism of the increase in blood pressure is unknown. To address this question we tested autonomic nervous system function and blood pressure regulation in RGS2-deficient mice (RGS2-/-). ...
Sollers John J JJ - - 2005
Typically, blood pressure variability has been calculated by taking the simple mathematical standard deviations of a collection of discrete blood pressure (BP) measurements. Recently, spectral analytic techniques have been employed to examine beat-to-beat blood pressure variability and the underlying autonomic adjustments associated with the performance of various tasks. In the ...
Harinath Kasiganesan - - 2005
OBJECTIVE: To evaluate the role of the autonomic nervous system and adrenal system in acclimatization to cold in tropical men during short or prolonged sojourns at Antarctica. METHODS:The study was carried out on volunteers of the 18th winter over team (WOT) and 19th summer team (ST) of an Indian Antarctic ...
Sosnowski Maciej - - 2005
BACKGROUND: The scatterplot of R-R intervals has several unique features. Its numerical evaluation may produce a new useful index of global heart rate variability (HRV) from Holter recordings. METHODS: Two-hundred and ten middle-aged healthy subjects were enrolled in this study. The study was repeated the next day in 165 subjects. ...
Grimm David R - - 2005
OBJECTIVE: To determine differences in peripheral and cardiovascular autonomic function between individuals with acute musculoskeletal injury (<1 week) and healthy controls. METHODS: Autonomic cardiovascular modulation, baroreceptor sensitivity, skin conductance, and peripheral skin temperature were obtained in 6 subjects with acute musculoskeletal injury and 6 age- and sex-matched controls. Power spectral ...
Sacha Jerzy - - 2005
Heart rate variability (HRV) spectrum can be calculated from the R-R or the sequence of instantaneous heart rates (IHRs). Because these signals are reciprocal, their use in the determination of the correlation of HRV with average HR may yield opposite results. AIM: The aim of this study is to reveal ...
Murialdo G - - 2005
BACKGROUND: Recombinant human thyrotropin (rhTSH) is now currently used for the follow-up of patients with differentiated thyroid carcinoma (DTC) after total thyroid ablation. Side effects after rhTSH could involve the autonomic system and TSH receptors are possibly expressed in the heart and coronary arteries. METHODS:Heart rate variability (HRV), studied by ...
Baartscheer Antonius - - 2005
OBJECTIVE: In patients with heart disease, the transition from compensatory hypertrophy to heart failure (HF) is associated with altered calcium handling. Up-regulated Na(+)/H(+)-exchanger (NHE-1) activity underlies increased [Na(+)](i) and disturbance of cellular calcium handling in HF. We hypothesize that chronic inhibition of NHE-1 activity prevents the hypertrophic response, cellular remodeling, ...
Saito Shigeru - - 2005
Autonomic nervous systems have important roles for survival of victims under hypobaric hypoxic condition. In the present study, we assessed the correlation between arterial oxygen saturation (Sp O 2 ) and heart rate variability (HRV) to identify the autonomic nervous responsiveness among trekkers at high altitude (n = 21). HRV ...
Lee Myeong Soo - - 2005
Heart rate variability (HRV) was compared in 30 subjects receiving external Qi therapy (EQT) or placebo control therapy, in a crossover design experiment. Subjects who received the EQT reported more pleasant and calm emotions than did the placebo group. Qi therapy reduced the heart rate and increased HRV as indicated ...
Park Mi-Kyong - - 2005
This study investigated the physiological and psychological effects of sanitary napkins (SN) on women in hemorrhage treatment during the menstrual phase. Mesh and non-woven napkins were employed, and the effects were studied during the follicular and menstrual phases; mesh SN presented a higher textural surface-roughness. In both phases, the increases ...
Moreno Javier - - 2005
OBJECTIVE: The dynamics of ventricular fibrillation (VF) in the presence of heart failure (HF) are different from those in the normal heart. This has been attributed solely to HF-induced electrophysiologic remodelling. We hypothesized that acute stretch and ischaemia, which are normally present during VF, might contribute significantly to the altered ...
Yates Bill J BJ Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15213, USA. - - 2005
The loss of labyrinthine inputs in patients or animal models has been demonstrated to affect autonomic regulation. Considerable evidence suggests that vestibular-autonomic responses serve to adjust blood pressure and respiratory activity during movement and postural alterations. However, following peripheral vestibular lesions, compensation rapidly occurs, such that autonomic disturbances are not ...
Lin Zheng Z Dept. of Biomed. Eng., Southern California Univ., Los Angeles, - - 2005
Studies suggest that obstructive sleep apnea syndrome (OSAS) is causally related to abnormal cardiovascular autonomic control in adults, but this has not been established in pediatric OSAS. The goal of this study was to quantify autonomic system dysfunction, as manifested by cardiovascular response abnormalities, in children with OSAS. During wakefulness, ...
Lin Zheng Z Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, - - 2005
Studies suggest that Obstructive Sleep Apnea Syndrome (OSAS) is causally related to abnormal cardiovascular autonomic control in adults, but this has not been established in pediatric OSAS. The goal of this study was to quantify autonomic system dysfunction, as manifested by cardiovascular response abnormalities, in children with OSAS. During wakefulness, ...
Cho Sung-Kang - - 2005
It has been previously known that low-dose atropine (LDA) enhances vagal outflow to the heart. To demonstrate the importance of vagal cardiac modulation in arterial blood pressure (ABP) stability, we evaluated the effect of vagal cardiac stimulation with administration of LDA on ABP fluctuation during dynamic hypertensive and hypotensive stimuli. ...
Nollo Giandomenico - - 2005
Although in physiological conditions RR interval and systolic arterial pressure (SAP) are likely to interact in a closed loop, the traditional cross-spectral analysis cannot distinguish feedback (FB) from feedforward (FF) influences. In this study, a causal approach was applied for calculating the coherence from SAP to RR (K(s-r)) and from ...
Chen Yanfang - - 2005
Studies examined the role of angiotensin (ANG) AT1a receptors in cardiovascular autonomic control by measuring arterial pressure (AP) and heart rate (HR) variability and the effect of autonomic blockade in mice lacking AT1a receptors (AT1a -/-). Using radiotelemetry in conscious AT1a +/+ and AT1a -/- mice, we determined 1) AP ...
Nakao Mutsuhiro - - 2004
This study examined the relationship between arterial stiffness and autonomic nervous function in a young population. A cross-sectional study was conducted on 382 Japanese males, aged 24 to 39 years, who worked at the same information service company. Brachial-ankle pulse wave velocity (baPWV) was measured using an automatic waveform analyzer, ...
Montebugnoli Lucio - - 2004
BACKGROUND: The authors conducted a study to evaluate the sensitivity of heart rate variability, or HRV, in quantifying the cardiocirculatory reaction to dental stress compared with other clinical parameters more frequently used in clinical practice. METHODS: Twenty-five healthy subjects (15 men and 10 women aged 19 through 73 years) who ...
Ditor David S - - 2005
Individuals with spinal cord injury are prone to cardiovascular dysfunction and an increased risk of cardiovascular disease. Body weight-supported treadmill training (BWSTT) may enhance ambulation in individuals with incomplete spinal cord injury; however, its effects on cardiovascular regulation have not been investigated. The purpose of this study was to examine ...
Neumann Senna A - - 2004
This study investigated the relation of dispositional hostility to cardiovascular reactivity during an anger-recall task and of hostility and distraction to posttask recovery in 80 healthy women (ages 18-30). Half were randomly assigned to distraction during recovery. Hostility predicted slower systolic blood pressure and preejection period during recovery. Distraction was ...
Struzik Zbigniew R - - 2004
We present systematic evidence for the origins of 1/f -type temporal scaling in human heart rate. The heart rate is regulated by the activity of two branches of the autonomic nervous system: the parasympathetic (PNS) and the sympathetic (SNS) nervous systems. We examine alterations in the scaling property when the ...
Kim Eun-Joo - - 2004
To investigate the safety pharmacology of a novel fluoroquinolone antibiotic agent, DW-224a, on the vital functions, we studied its effects on the central nervous system, cardiovascular system and respiratory system. To determine the effects on the central nervous system, we used a modified Irwin's test at each time point after ...
Farah Vera M A - - 2004
There is evidence that alterations in heart rate and blood pressure variability (BPV) are associated with cardiovascular disease. We used a mice model to investigate the effects of acute and chronic stress on blood pressure variability (BPV) and heat rate variability (HRV). Shaker stress was given acutely (5 min, 150 ...
Cooke William H - - 2005
The purpose of this study was to test the hypothesis that high-intensity strength training increases vagal-cardiac control and cardiovagal baroreflex sensitivity. Twenty-two subjects [age 22 (0.8) years] were assigned to either strength training (ST, n=12) or control (CON, n=10) groups. Subjects in the ST group trained each major muscle group ...
Stemper B - - 2004
OBJECTIVE: To assess the possible abnormalities in the baroreflex modulation of both the heart and the arterial vasculature, in order to better evaluate the role of baroreflex abnormalities in the generation of the cardiovascular symptoms and complications affecting the familial dysautonomia (FD) patient. METHODS: Twenty-one FD patients and 22 controls ...
Cogliati Chiara - - 2004
BACKGROUND: The possible mechanisms by which beta-adrenergic antagonists may act on the neural regulation of the cardiovascular system are still elusive. Recent studies reported a marked increase of postganglionic muscle sympathetic nerve activity (MSNA) after acute beta-blockade associated with unchanged values of arterial blood pressure and baroreflex sensitivity. We tested ...
Rassi D - - 2005
BACKGROUND AND AIM: A fuller understanding of the neural control mechanisms of heart rate during the early stages of human development would be of great value to obstetric and neonatal management. In this paper, we investigate the correlation between heart rate variability (HRV) and other physiological parameters such as blood ...
Randall David C - - 2005
This study quantified the effect of interrupting the descending input to the sympathetic preganglionic neurons on the dynamic behavior of arterial blood pressure (BP) in the unanesthetized rat. BP was recorded for approximately 4-h intervals in six rats in the neurally intact state and in the same animals after complete ...
Lenard Zsuzsanna - - 2004
BACKGROUND: Cardiovagal autonomic control declines with age in adult subjects, which is related in part to increasing stiffness of the barosensory vessel wall. It is not known, however, whether autonomic function changes with age in children. METHODS AND RESULTS: We studied 137 healthy subjects divided into 4 age groups: group ...
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