Search Results
Results 301 - 350 of 1815
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Deschamps Alain - - 2009
Because anesthesia affects the integrity of the autonomic nervous system, anesthesiologists use vital signs to maintain respiratory and circulatory homeostasis. However, patients with genetic predispositions or with autonomic dysfunctions are at risk of severe complications from anesthesia. For these patients, the monitoring of vital signs may not give sufficient warning ...
Milic Milos - - 2009
Phenylephrine bolus injection is an established technique to measure baroreflex sensitivity (BRS). This study quantified the relationship between the phenylephrine method and noninvasive measures of BRS and examined the effects of aging and hypertension on BRS. We also examined whether heart rate variability (HRV) provides as much information as does ...
Nilsen K B - - 2009
OBJECTIVES: We investigated whether spontaneous baroreflex sensitivity and heart rate variability (HRV) are different in migraine patients compared to healthy controls. MATERIAL AND METHODS: Sixteen female migraine patients without aura aged 18-30 years and 14 age-matched healthy female controls were included. Continuous finger blood pressure and ECG were measured supine ...
Wensel R - - 2009
Pulmonary arterial hypertension (PAH) results in chronic right heart failure, which is associated with an increase in sympathetic tone. This may adversely affect cardiac autonomic control. We investigated the changes in cardiac autonomic nervous activity in relation to disease severity in patients with PAH. In 48 patients with PAH (median ...
Sykora Marek - - 2009
BACKGROUND: Perihematomal edema and secondary brain injury may influence the clinical course after intracerebral hemorrhage (ICH). The role of blood pressure (BP) in edema formation in ICH has not been studied sufficiently. We hypothesize that impaired blood pressure regulation (as measured by baroreflex sensitivity) leading to excessive BP fluctuations may ...
Zhang Rong - - 2009
To assess baroreflex function under closed-loop conditions, a new approach was used to generate large and physiological perturbations in arterial pressure. Blood pressure (BP) and R-R interval were recorded continuously in 20 healthy young (33 +/- 8 yr) and eight elderly subjects (66 +/- 6 yr). Repeated squat-stand maneuvers at ...
Kishi Takuya - - 2009
N-type calcium channel blocker, cilnidipine, is reported not to increase the heart rate in spite of the strong depressor effect. However, it has not been determined whether cilnidipine has the sympatho-inhibitory effects or not. Moreover, the effect of cilnidipine on the baroreflex control has not been determined. The aim of ...
Okano Yasuko Y Department of Medical Science and Cardiorenal Medicine, Yokohama City University, Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku,Yokohama City, Japan. - - 2009
We report the relationship between 24-hour (24-h) blood pressure, autonomic function, and health-related quality of life (HRQOL) in normotensives and hypertensives. The aim of this study was to determine whether there is a relationship between 24-h blood pressure, autonomic function, and HRQOL during treatment with an angiotensin receptor blocker (ARB) ...
El-Mas Mahmoud M - - 2009
1. Published data concerning the effects of ovarian hormones on haemodynamic variability are contradictory. For the first time, the present study used radiotelemetric haemodynamic monitoring to investigate the long-term effects of chronic oestrogen depletion and repletion on cardiovascular autonomic control and arterial baroreflex sensitivity (BRS) in female rats. 2. Blood ...
Fakhri Asghar A AA Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, - - 2009
Human controlled-exposure studies have assessed the impact of ambient fine particulate matter on cardiac autonomic function measured by heart rate variability (HRV), but whether these effects are modified by concomitant ozone exposure remains unknown. In this study we assessed the impact of O(3) and particulate matter exposure on HRV in ...
Aubert André E - - 2009
Oscillations of heart rate and blood pressure are related to the activity of the underlying control mechanism. They have been investigated mostly with linear methods in the time and frequency domains. Also, in recent years, many different nonlinear analysis methods have been applied for the evaluation of cardiovascular variability. This ...
Di Rienzo M - - 2009
The aim of this paper is to highlight the aspects of the baroreflex control of the cardiovascular system that could be relevant to the analysis and modelling of cardiovascular oscillations and regulation. In particular, complex and/or controversial issues of the baroreflex control are addressed on the basis of results obtained ...
Metcalf Cameron S - - 2009
PURPOSE: Status epilepticus (SE) activates the autonomic nervous system, increasing sympathetic nervous system control of cardiac function during seizure activity. However, lasting effects of SE on autonomic regulation of the heart, which may contribute to mortality following seizure activity, are unknown. Therefore, autonomic control of cardiac function was assessed following ...
Silva G J J - - 2009
The autonomic nervous system plays an important role in physiological and pathological conditions, and has been extensively evaluated by parametric and non-parametric spectral analysis. To compare the results obtained with fast Fourier transform (FFT) and the autoregressive (AR) method, we performed a comprehensive comparative study using data from humans and ...
Cekici Leyla - - 2009
To investigate short-term effects of inhaled salbutamol on haemodynamic changes and cardiovascular autonomic control. A randomized, single-blinded, placebo-controlled study of 0.2 mg of inhaled salbutamol was conducted on 12 healthy nonsmoking volunteers with a mean age of 24 +/- 2 years at two different testing sessions. Non-invasively obtained continuous haemodynamic ...
Aletti Federico - - 2009
In order to analyze the information carried by arterial blood pressure (ABP) variability, a multivariate parametric model of interactions involving systolic ABP (SAP), diastolic ABP (DAP), pulse pressure (PP), heart period (HP), and respiration is proposed. The model defines SAP as sum of the preceding DAP and PP values; DAP ...
Tang Xiaorui - - 2009
A consistent and prominent feature, observed across many species, including our neuromuscular blocked (NMB) rat preparation, is that obliterating the baroafferent inputs to the brainstem, e.g., by sinoaortic denervation (SAD), significantly increases blood pressure variability (BPV). The sources of the BPV, however, are not completely understood, but involve both the ...
McConnell Keith - - 2009
We previously demonstrated that children with obstructive sleep apnea have increased blood pressure associated with changes in left ventricular mass index. Others have shown in adults that blood pressure variability is an important predictor of changes in left ventricular mass. The baroreflex system buffers blood pressure changes by varying heart ...
Castiglioni Paolo - - 2009
Heart rate self-affinity is often assessed by detrended fluctuations analysis, obtaining two coefficients only: a short-term (alpha(1)) exponent and a long-term (alpha(2)) exponent. Our aim is to show the limits of this approach and alternatively propose the estimation of the whole spectrum of local exponents alpha(n) for heart rate and ...
Tharion Elizabeth - - 2009
BACKGROUND: Heart rate variability measures are reported to be altered in patients with various diseases, implying related abnormality of cardiac autonomic function. Could associated anxiety-induced mental stress, invariably present in all patients, contribute to these alterations? To address this question, we compared heart rate variability parameters computed from students during ...
Ferretti Guido - - 2009
BACKGROUND: Physical inactivity represents a major risk for cardiovascular disorders, such as hypertension, myocardial infarction or sudden death; however, underlying mechanisms are not clearly elucidated. Clinical and epidemiological investigations suggest, beyond molecular changes, the possibility of an induced impairment in autonomic cardiovascular regulation. However, this hypothesis has not been tested ...
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 ...
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