Search Results
Results 301 - 350 of 1782
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Tang Collin H H - - 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. ...
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 ...
Magagnin V - - 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 ...
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, ...
Tiinanen Suvi - - 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). ...
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 ...
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 - - 2009
OBJECTIVE: To identify autonomic dysregulation in frontal lobe epilepsy (FLE). METHODS: 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 ...
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 ...
Hempel R J - - 2009
This study aimed to investigate the effects of treatment with haloperidol, olanzapine and risperidone on cardiovascular variability in patients with recent-onset schizophrenia by means of spectral analysis. Unmedicated patients (n = 18) had a higher mean heart rate and a tendency for a lower high-frequency power of heart rate variability ...
Farr Mary Jane - - 2008
The response to cardiopulmonary exercise (CPX) in patients with heart failure (HF) with normal left ventricular (LV) ejection fractions (EFs) is not well characterized. To determine if CPX testing could distinguish between patients with HF with normal EFs (>50%; i.e., diastolic HF) and those with decreased EFs (> or =50%; ...
Otsuka Yasuko - - 2008
To examine the orthostatic influence on heart rate and blood pressure variability in persons with tetraplegia playing wheelchair basketball, ten trained persons with tetraplegia, ten untrained persons with tetraplegia, and ten able-bodied participated in this study. Spectrum analysis of the ECG R-R interval and blood-pressure on a beat-by-beat basis during ...
Cooke William H - - 2008
OBJECTIVE: To test the hypothesis that components of heart period variability track autonomic function during simulated hemorrhage in humans. DESIGN: Prospective experimental laboratory intervention. SETTING: Human physiology laboratory. SUBJECTS: A total of 33 healthy, nonsmoking, volunteer subjects (23 men, ten women). INTERVENTIONS: Progressive lower body negative pressure was applied in ...
Studinger Péter - - 2008
BACKGROUND: Peripheral blood pressure measurement underestimates pressure changes during baroreflex testing, resulting in an overestimation of baroreflex gain. This error might be reduced by measuring central blood pressure; the invasive measurement, however, may represent ethical and practical problems. The solution may be the derivation of central blood pressure from the ...
Wu Jin-Shang - - 2008
OBJECTIVES: This study sought to examine the hypothesis that cardiac autonomic function (CAF) is altered in pre-hypertensive subjects and normotensive subjects with a family history of hypertension (FHH). BACKGROUND: The findings on the FHH effect in CAF have been inconsistent, and little is known about altered CAF in pre-hypertensive subjects ...
Wiegerinck Rob F - - 2008
BACKGROUND: Heterogeneity of repolarization and conduction is a potential source of arrhythmogenesis. In heart failure (HF), intercellular coupling is reduced and heterogeneities may become evident because of reduced intercellular coupling. OBJECTIVE: This study sought to investigate connexin43 (Cx43) expression, conduction velocity (CV), refractoriness and inducibility of arrhythmias at multiple sites ...
Bettencourt M Joaquina - - 2008
In a previous work we studied, non-invasively, autonomic nervous system control of circulation in healthy subjects, observing the hemodynamic reaction to active standing. We now propose to extend this analysis to essential hypertension (EH), investigating possible autonomic dysfunction. The cardiovascular response to postural change from the supine position to active ...
Liu David S - - 2008
This study attempted to use the eyesight range to quantify presyncope symptoms (PS), assess the relation between angle of head-up tilt, severity of injury on the American Spinal Injury Association (ASIA) scale, and PS on physiological signals, and determine the notable signals that represent PS in spinal cord injury (SCI) ...
Renaud Guillaume - - 2008
To study "non-classical" acoustical nonlinearities in cracked materials, we developed a nonlinear (NL) wave coupling technique. Propagation velocity and amplitude of short high-frequency (HF, 600 kHz) bursts are modulated as result of nonlinear interaction with a low-frequency (LF, 3 kHz) wave. Time Of Flight Modulation (TOFM) is indeed related to ...
Fazan Rubens R - - 2008
Sildenafil induces vasodilation and is used for treating erectile dysfunction. Although its influence on resting heart function appears to be minimal, recent studies suggest that sildenafil can increase sympathetic activity. We therefore tested whether sildenafil injected into the central nervous system alters the autonomic control of the cardiovascular system in ...
Xavier Rita - - 2008
The Valsalva maneuver is an autonomic test that evokes short sharp cardiovascular fluctuations mediated by the autonomic nervous system. Numerous spectral analysis methods have been proposed to analyze biological signals. When applied to heart rate (HR) variability, two major bands related to autonomic influence have been defined: LF (mainly sympathetic) ...
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