Search Results
Results 351 - 400 of 1844
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Mulder L J M - - 2009
Adaptive support has the potential to keep the operator optimally motivated, involved, and able to perform a task. In order to use such support, the operator's state has to be determined from physiological parameters and task performance measures. In an environment where the task of an ambulance dispatcher was simulated, ...
Takamoto Kohichi - - 2009
Massotherapy, the therapeutic use of massage, is used to treat various chronic pain syndromes. One type of massotherapy, pressure stimulus applied over trigger points (TPs), is reported to have excellent therapeutic effects. Its effect is possibly mediated through changes in the autonomic nervous system although little research has been conducted ...
Gray Marcus A - - 2009
Central nervous processing of environmental stimuli requires integration of sensory information with ongoing autonomic control of cardiovascular function. Rhythmic feedback of cardiac and baroreceptor activity contributes dynamically to homeostatic autonomic control. We examined how the processing of brief somatosensory stimuli is altered across the cardiac cycle to evoke differential changes ...
Ogungbemi, SI; Department of ...
This study examined the effect of chronic, low dose vitamin C supplementation on the baro-reflex sensitivity (BRS), rate - pressure product (RPP) and Barach energy index (BEI) in 21 male athletes and sickle cell anaemia subjects (SCAS). Arterial blood pressure and heart rate were recorded in the supine position and ...
Mokra Daniela - - 2009
BACKGROUND: Because cardiovascular functions and their control mechanisms may be influenced by meconium aspiration and by treatment, cardiovascular parameters including heart rate variability (HRV) were evaluated after meconium instillation and treatment with dexamethasone. METHODS: Adult rabbits were anesthetized, paralyzed, and artificially ventilated. Meconium suspension (25 mg/mL, 4 mL/kg) was instilled ...
Martos Ramón - - 2009
Heart failure with preserved ejection fraction (HF-PEF) can be difficult to diagnose in clinical practice. Myocardial fibrosis is a major determinant of diastolic dysfunction (DD), potentially contributing to the progression of HF-PEF. The aim of this study was to analyse whether serological markers of collagen turnover may predict HF-PEF and ...
Huang Shu-Chun - - 2009
This study investigates how various hypoxic interventions affect cardiac autonomic activity and hemodynamic control during posture change and the Valsalva maneuver. Ten healthy sedentary men exposed to 12, 15 and 21% O(2) for 1 h in a normobaric hypoxia chamber in a random order. Before and after various O(2) concentrations ...
Fang Shona C - - 2009
Patients with health conditions associated with impaired vascular function and inflammation may be more susceptible to the adverse health effects of fine particulate (particulate matter with a mass median aerodynamic diameter of </=2.5 mum (PM(2.5))) exposure. In 2006, the authors conducted a panel study to investigate directly whether vascular function ...
McGowan C L - - 2009
OBJECTIVES: To determine, in patients with pulmonary arterial hypertension (PAH), whether there is a relationship: (1) between sympathetic nerve firing rate and spectral indices of sympathetic neural heart rate modulation; and (2) between heart rate variability (HRV) and right atrial pressure, a stimulus to sinoatrial node stretch. DESIGN: Characterisation of ...
Okita Yoshimitsu - - 2009
The aim of this study was to investigate the effects of vegetable tablets containing Gamma-Aminobutyric Acid (GABA) intake on cardiovascular response and the autonomic nervous system in young adults. In a double-blind, randomized controlled trial, 7 healthy subjects were assigned to take vegetable tablets (10 g/trial) or control tablets (10 ...
Peng Shu-Ming - - 2009
OBJECTIVE: The purpose of the present study was to investigate the effect of listening to soft music or inhaling Citrus bergamia aroma on autonomic nervous system activity in young healthy individuals. STUDY DESIGN, LOCATION, AND SUBJECTS: This single-institution study was an open-label randomized controlled trial carried out on 114 healthy ...
Fallo F - - 2009
Cardiac autonomic dysfunction is associated with increased cardiovascular mortality. No data on sympathovagal balance are available in patients with Cushing's syndrome, in whom cardiovascular risk is high. We studied 10 patients with newly diagnosed Cushing's syndrome (1 male/9 females; age mean+/-SD, 47+/-10 yr) and 10 control subjects matched for age, ...
Pantoni Camila Bianca Falasco - - 2009
Noninvasive positive pressure has been used to treat several diseases. However, the physiological response of the cardiac autonomic system during bilevel positive airway pressure (Bilevel) remains unclear. The aim of this study was to evaluate the heart rate variability (HRV) during Bilevel in young healthy subjects. Twenty men underwent 10-minute ...
Furukawa Taiji - - 2009
BACKGROUNDS AND METHODS: A higher degree of clinical efficacy with olmesartan compared with other angiotensin receptor blockers, has been reported by several sources. In this study of 31 examples of cases of essential hypertension, Holter electrocardiogram, ambulatory blood pressure monitoring and pulse wave velocity (PWV) measurements were performed before and ...
Magagnin V V Orthopaedic Institute IRCCS Galeazzi, Milano, Italy. - - 2009
Estimation of the baroreflex gain has become an important tool in clinical practice in order to assess cardiac autonomic system control. Spectral analysis and sequence analysis techniques based on the spontaneous variability of systolic arterial pressure and heart period have been proposed to evaluate the baroreflex gain. These analyses can ...
Yambe Tomoyuki T Tohoku University, 4-1 Seryo-machi, Aoba-ku, Sendai 980-8575, Japan. - - 2009
Text book in all medical school showed that the baroreflex system is one of the most important regulatory systems. When blood pressure increases, heart rate decrease and an artery is dilated with the baroreflex system. By decrease of cardiac output and arterial resistances, blood pressure returns to the normal value. ...
Tang Collin H H CH School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052, Australia. - - 2009
Sepsis is characterized by profound cardiovascular abnormalities which may result from the derangements in the arterial baroreflex system and other autonomic regulatory functions. In this study, a mechanically ventilated and anesthetized rabbit model of endotoxic shock was utilized to mimic the behaviors of the cardiovascular system in a sepsis patient. ...
Tiinanen Suvi S Department of Electrical and Information Engineering, PO BOX 4500, 90014 University of Oulu, Finland. - - 2009
Altering cardiovascular oscillation is present during various interventions, e.g. in autonomic tests. Traditional spectral analysis suffers from nonstationary data and poor time resolution when studying the dynamics and frequency of cardiovascular signals. Smoothed pseudo Wigner-Ville representation method was applied when analyzing handgrip (HG) data of healthy men (n = 11). ...
Abe Makoto M Research Division on Advanced Information Technology, Cyberscience Center, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8579, Japan. - - 2009
The maximum cross-correlation coefficient rho(max) between blood pressure variability and heart rate variability, whose frequency components are limited to the Mayer wave-related band, is a useful index to evaluate the state of the autonomic nervous function related to baroreflex. However, measurement of continuous blood pressure with an expensive and bulky ...
Sala-Mercado Javier A JA Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201 USA. - - 2009
We performed a pilot investigation of the cardiopulmonary baroreflex control of ventricular contractility in two conscious dogs. We specifically measured spontaneous beat-to-beat hemodynamic variability before and after the administration of propranolol. We then identified the transfer function relating beat-to-beat fluctuations in central venous pressure (CVP) to maximal ventricular elastance (E(max)) ...
Deley Gaelle - - 2009
Exaggerated pressor responses to mental stress in patients with coronary artery disease (CAD) are associated with increased risk for subsequent cardiovascular events. The integrated baroreflex gain and its mechanical and neural component were estimated and then related to the blood pressure and heart rate responses to simulated real-life stressors: mental ...
Grasser E K - - 2009
We investigated non-invasively cardiac contractility and autonomic nervous activity during presyncopal orthostatic stress induced in healthy humans. A graded orthostatic stress (GOS) paradigm, consisting of head-up tilt (HUT) combined with lower body negative pressure (LBNP) of increasing magnitude, was used to reach a presyncopal end-point in 15 healthy adults. Continuous ...
Yazici Mehmet - - 2008
OBJECTIVE: Non-invasive mechanical ventilation (NIMV) has the potential to improve sympathovagal control of heart rate. The aim of this study was to investigate the acute effects of NIMV on heart rate variability (HRV) in chronic obstructive pulmonary disease (COPD) patients with hypercapnic respiratory failure (HRF). METHODS: In this prospective study ...
Okushima Koki - - 2008
OBJECTIVE: We investigated the effects of conscious sedation by 30% nitrous oxide inhalation on the cardiac autonomic nervous system in the absence or presence of music listening. STUDY DESIGN: The power spectral analysis of heart rate variability (HRV) and cardiovascular parameters were measured in 26 healthy volunteers, who were divided ...
Javorka M - - 2009
The purpose of this paper is to investigate the effect of orthostatic challenge on recurrence plot based complexity measures of heart rate and blood pressure variability (HRV and BPV). HRV and BPV complexities were assessed in 28 healthy subjects over 15 min in the supine and standing positions. The complexity ...
Kashihara Koji - - 2009
The assessment of arterial baroreflex function in cardiovascular diseases requires quantitative evaluation of dynamic and static baroreflex properties because of the frequent modulation of baroreflex properties with unstable hemodynamics. The purpose of this study was to identify the dynamic baroreflex properties from transient changes of step pressure inputs with background ...
Pagani Massimo - - 2009
BACKGROUND: Sleep disorders are associated to a number of cardiovascular disturbances that might increase cardiovascular risk. Sleep deprivation, in particular, might, by inducing autonomic dysregulation, raise arterial pressure and hypertensive risk. Available evidence however is contradictory. METHODS: We tested the main hypothesis that one night sleep deprivation in 24 volunteers ...
Honz??kov?? N - - 2009
It has been known for many years that baroreflex sensitivity is lowered in hypertensive patients. There are several known factors implicating this association, e.g. high blood pressure leads to remodeling of the carotid arterial wall, to its stiffness and to a diminished activation of baroreceptors; leptin released from a fatty ...
Tang Hsin-Yi Jean - - 2008
The purpose of this pilot study was to evaluate the effectiveness of an audio relaxation tool for lowering blood pressure and augmenting heart rate variability (HRV) in older adults. Fourteen older adults (83 +/- 8 years) participated in the study. The intervention consisted of 12 sessions of a guided relaxation ...
Van de Louw Andry - - 2008
Heart rate and blood pressure variations during spontaneous ventilation are related to the negative airway pressure during inspiration. Inspiratory airway pressure is positive during mechanical ventilation, suggesting that reversal of the normal baroreflex-mediated pattern of variability may occur. We investigated heart rate and blood pressure variability and baroreflex sensitivity in ...
Pal G K - - 2009
Presently, essential hypertension (EH) is among the most common morbid disorders of mankind. The fundamental pathophysiology of EH is sympathetic overactivity. It has been observed that the people having common risk factors for hypertension such as obesity, insulin resistance and stress generally have increased sympathetic activity. Therefore, it is presumed ...
Pavithran P - - 2008
We sought to evaluate oxidative stress parameters like malondialdehyde, total antioxidant status, and time, frequency domain heart rate variability indices in newly diagnosed untreated hypertension. We also sought to study the correlation between heart rate variability and oxidative stress parameters in normotensive and newly diagnosed untreated essential hypertensives. Fourteen normotensive ...
Duschek Stefan - - 2008
This study investigated aberrations in baroreflex function and cardiovascular reactivity related to the condition of chronic low blood pressure. In 40 hypotensive and 40 normotensive control subjects, blood pressures were continuously recorded at rest and during mental stress. Baroreflex sensitivity was determined in the time domain using sequence analysis. Beat-to-beat ...
Cividjian A - - 2008
BACKGROUND: Pressure lability may be linked to the loss of the cardiac baroreflex. The reduction of the sensitivity of the cardiac baroreflex has not been delineated in the post-operative period according to age in normotensive patients. This study addresses pressure lability and slope of the cardiac baroreflex as a function ...
Goedhart Annebet D - - 2008
It has been hypothesized that the ratio of heart rate variability in the low- (LF) and high- (HF) frequency bands may capture variation in cardiac sympathetic control. Here we tested the temporal stability of the LF/HF ratio in 24-h ambulatory recordings and compared this ratio to the preejection period (PEP), ...
Mäkelä Petri - - 2008
The blood pressure-lowering mechanism of low-sodium diet is not fully understood. We assessed the effects of salt restriction on cardiac parasympathetic function as measured by heart-rate variability (HRV) in mild to moderate hypertensive patients. Eighty patients were randomized to a 6-month low- (N = 40) or normal (N = 40) ...
Lin Y-D - - 2008
BACKGROUND: Our team previously demonstrated arterial stiffening and cardiac hypertrophy in type 2 diabetic rats at 8 but not 4 weeks after being administered streptozotocin (STZ) and nicotinamide (NA). The present study focused on investigating the effects of type 2 diabetes on cardiac autonomic nerve function in the STZ- and ...
Chan Christopher T - - 2008
BACKGROUND: In patients with end-stage renal disease receiving conventional hemodialysis, both the frequency with which brief rises or falls in systolic blood pressure initiate concordant changes in pulse interval (arterial baroreflex effectiveness index), and the gain of reflex heart rate responses to these stimuli (arterial baroreflex sensitivity) are diminished. In ...
Zhang Li-Fan - - 2008
This study was designed to test the hypothesis that postsuspension cardiovascular manifestation in conscious rats after a medium-term (28-day) tail suspension (SUS) is hypertensive and tachycardiac and can be prevented by a countermeasure of daily 1-h dorsoventral (-G(x)) gravitation provided by standing (STD). To assess associated changes in cardiovascular regulation, ...
Liu S - - 2008
The aim of the study was to evaluate the therapeutic value and possible mechanisms of transcutaneous electroacupuncture (TEA) in a double-blind and cross-over study in patients with functional dyspepsia (FD). Twenty-seven patients with FD were enrolled and the study consisted of two parts: (i) acute effects of TEA at PC6 ...
Montano Nicola - - 2009
The neural regulation of circulatory function is mainly effected through the interplay of the sympathetic and vagal outflows. This interaction can be explored by assessing cardiovascular rhythmicity with appropriate spectral methodologies. Spectral analysis of cardiovascular signal variability, and in particular of RR period (heart rate variability, HRV), is a widely ...
Holman Andrew J - - 2008
To consider autonomic status as a predictor of anti-tumor necrosis factor (TNF) treatment response for inflammatory arthritis, we conducted an exploratory, double-blind, 52-week study with 33 patients with rheumatoid (25) or psoriatic (8) arthritis using heart rate variability (HRV). All were assessed for parasympathetic, sympathetic, total power and tension index ...
Harnod Tomor T Institute of Medical Sciences, Tzu Chi University, Hualien, - - 2009
To identify autonomic dysregulation in frontal lobe epilepsy (FLE). We studied 14 male and 11 female subjects with FLE and an equal number of matched healthy control subjects. Lead I electrocardiograms were obtained for 5 min in the interictal state during daytime. Frequency-domain analysis of heart rate variability was performed ...
Goernig Matthias - - 2008
BACKGROUND: Autonomic regulation analysis is useful in risk stratification of ventricular tachycardia and sudden cardiac death in chronic heart failure (CHF). Heart rate variability (HRV) reflects the condition of autonomic regulation. For analyzing the autonomic control the whole cardiovascular system has to be considered. Therefore, the aim of our study ...
Santarcangelo Enrica L - - 2008
Heart rate and heart-rate variability (HRV) were studied through a set of different methods in high (highs) and low hypnotizable subjects (lows) not receiving any deliberate hypnotic induction in basal conditions (simple relaxation) and during nociceptive-pressor stimulation with and without suggestions of analgesia. ANOVA did not reveal any difference between ...
Pavithran Purushothaman - - 2008
BACKGROUND: It has been well established that hypertension is associated with autonomic dysregulation. Studies investigating HRV have established that hypertension is characterized by sympathetic overactivity and or attenuation of parasympathetic modulation of the heart. METHODS: We examined short-term heart rate variability (HRV) as well as conventional indices of cardiovascular autonomic ...
Alyan Omer - - 2008
OBJECTIVE: Percutaneous balloon valvulotomy (PBV) is the procedure of choice for the treatment of valvular pulmonary stenosis (PS) with similar results comparable to surgical valvotomy but less invasive. METHODS AND RESULTS: Twenty-seven consecutive patients with PS being evaluated for PBV were enrolled in the study. Peak instantaneous transvalvular gradient, right ...
Chang Shyang - - 2008
The aims of this study were to investigate (i) if and when the blood pressure would rise or fall and (ii) the associated changes of human heart rate variability (HRV) by manual stimulation of the Neiguan (PC 6) acupuncture site. In this paper, two groups of six healthy male volunteers ...
Rinne Petteri - - 2008
Melanocyte stimulating hormones (MSH) derived from pro-opiomelanocortin have been demonstrated to participate in the central regulation of cardiovascular functions. The aim of the present study was to elucidate the chronic effects of increased melanocortin activation on blood pressure regulation and autonomic nervous system function. We adapted telemetry to transgenic mice ...
Borghi-Silva Audrey - - 2008
OBJECTIVE: The purpose of present study was to evaluate the acute effects of bi-level positive airway pressure (BiPAP) on heart rate variability (HRV) of stable chronic obstructive pulmonary disease patients (COPD). METHODS: Nineteen males with COPD (69+/-8 years and with forced expiratory volume in 1s <50% of predicted) and eight ...
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