Search Results
Results 551 - 600 of 1782
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Green Daniel J - - 2006
AIMS: We examined the thermoregulatory response to heat exposure in patients with chronic heart failure. METHODS AND RESULTS: Skin blood flow (SkBF) was measured in HF subjects and matched controls. Cutaneous vascular conductance (CVC) was calculated from laser-Doppler SkBF and blood pressure. To assess the nitric oxide contribution to thermoregulatory ...
Masuki Shizue - - 2006
In the present study, we assessed whether heart rate (HR) or arterial pressure fluctuations are enhanced in healthy young humans with reduced alpha-adrenergic vasoconstrictor responses and, if so, whether this occurs for both alpha1- and alpha2-adrenergic receptor-mediated vasoconstriction. Arterial pressure (brachial artery catheter) and HR (ECG) were monitored continuously, and ...
Gottdiener John S - - 2006
The left atrium enlarges in association with many factors, including aging, atrial fibrillation, hypertension, diastolic dysfunction, and heart failure (HF) with low ejection fraction. However, left atrial (LA) volume, geometry, and emptying have not been compared between diastolic and systolic HF, nor has the association of LA volume for new ...
Kuriyama Nagato - - 2005
The clinical significance of evaluating autonomic nervous system functions in the early stages of olivopontocerebellar atrophy (OPCA) has been investigated in 13 OPCA out-patients (7 males and 6 females, mean age: 51.0 years). We have employed measurements of blood pressure, plasma norepinephrine (NE), CVR-R, low-frequency power/high-frequency power ratio (L/H), high-frequency ...
Obst Michael - - 2006
The regulator of G protein signaling (RGS) 2, a GTPase-activating protein, is activated via the nitric oxide (NO)-cGMP pathway and thereby may influence blood pressure regulation. To test that notion, we measured mean arterial blood pressure (MAP) and heart rate (HR) with telemetry in N(omega)-nitro-l-arginine methyl ester (l-NAME, 5 mg ...
Lewis Michael J - - 2005
Heart rate monitoring is commonly used to provide an acute indicator of an individual's cardiovascular status and responsiveness. An increasingly popular technique involves quantifying the very small amounts by which the heart rate changes from one cardiac cycle to the next. This "heart rate variability (HRV) analysis" provides a substantial ...
Chesterton Lindsay J - - 2005
PURPOSE OF REVIEW: Autonomic dysfunction is well recognized in chronic kidney disease. The baroreflex arc is an important component of the autonomic nervous system and influences vasodilatation and heart rate in response to information derived from baroreceptors located in the aorta and common carotid arteries. Appropriate regulation of systemic blood ...
Aronow Wilbert S - - 2006
Underlying causes, risk factors, and precipitating causes of heart failure (HF) should be treated. Drugs known to precipitate or aggravate HF should be stopped. Patients with HF and an abnormal left ventricular ejection fraction (LVEF) (systolic heart failure) or normal LVEF (diastolic HF) should be treated with diuretics if fluid ...
Waki Hidefumi - - 2006
At present, there is no single software package that provides a comprehensive power spectral analysis of pulse interval (PI) and arterial blood pressure (BP), spontaneous cardiac baroreceptor reflex gain (sBRG) and respiratory rate. Furthermore, scientific validation of the software that is currently commercially available and employed has not been published. ...
Timonen Kirsi L - - 2006
Previous studies have shown an association between elevated concentrations of particulate air pollution and cardiovascular morbidity and mortality. Therefore, the association between daily variation of ultrafine and fine particulate air pollution and cardiac autonomic control measured as heart rate variability (HRV) was studied in a large multicenter study in Amsterdam, ...
Lucini Daniela - - 2005
Elevated psychosocial stress might favor the occurrence of cardiovascular disease; however, mechanisms are incompletely understood. We hypothesized that patients (n=126; 44+/-1 years of age) referred to an internal medicine clinic because of symptoms related to chronic psychosocial stress would demonstrate signs of autonomic dysregulation compared with controls (n=132; 42+/-1 years ...
Reshef Naama - - 2005
BACKGROUND: Interventional studies have shown that increased intake of fruit and vegetables reduces blood pressure (BP). However, the contribution of specific dietary components has not been evaluated. The aim of the present study was to determine, in patients with stage I hypertension, the antihypertensive effect of juice of the so-called ...
Kataoka Y - - 2005
Bathing in Japanese style may carry negative effects as water pressure on the chest and thermal stimulus on hemodynamics take place. We have explored the influence of bathing in high temperature water on the change of heart rate variability (HRV). Fourteen young healthy male adults, ageing in range from 28 ...
Carrasco-Sosa S - - 2005
In the present study, we examined two baroreflex sensitivity (BRS) issues that remain uncertain: the differences among diverse BRS assessment techniques and the association between BRS and vagal outflow. Accordingly, the electrocardiogram and non-invasive arterial pressure were recorded in 27 healthy subjects, during supine with and without controlled breathing, standing, ...
Brook Robert - - 2005
Flow-mediated dilation (FMD) in the brachial artery is a widely used end point in clinical trials despite large within-subject variability and a small dynamic range. Recent studies suggest that the radial artery may be more advantageous for investigating FMD because of an enhanced vasodilator response. This study therefore assessed the ...
Pinna G D - - 2006
Paced breathing (PB) around 0.25 Hz has been advocated as a means to avoid confounding and to standardize measurements in short-term investigations of autonomic cardiovascular regulation. Controversy remains, however, as to whether it causes any alteration in autonomic control. We addressed this issue in 40 supine, middle-aged, healthy volunteers by ...
Javorka Michal - - 2005
Autonomic neuropathy and cardiovascular dysregulation are common complications of the diabetes mellitus (DM). The aim of the study was to test the hypothesis that cardiovascular regulation is abnormal in young patients with type 1 DM. Patients with type 1 DM (17, 10 females, 7 males) aged 12.9-31.5 years (mean+/-SEM: 22.4+/-1.0 ...
Gentlesk Philip J - - 2005
BACKGROUND: Modulation of sympathetic tone may contribute to statin-mediated reduction in sudden cardiac death. We examined the effect of simvastatin on heart rate variability (HRV) in patients with non-ischemic dilated cardiomyopathy to evaluate for an antisympathetic effect of statins independent of anti-ischemic properties. METHODS: The study was a prospective, open-label, ...
Bernardi L - - 2005
Respiration is a powerful modulator of heart rate variability, and of baro- or chemo-reflex sensitivity. This occurs via a mechanical effect of breathing that synchronizes all cardiovascular variables at the respiratory rhythm, particularly when this occurs at a particular slow rate coincident with the Mayer waves in arterial pressure (approximately ...
Myredal Anna - - 2005
BACKGROUND: Recent guidelines for the management of arterial hypertension have proposed that, to prevent cardiovascular disease, lifestyle modifications are required even in the case of high-normal blood pressure (HNBP). OBJECTIVE: To assess myocardial repolarization and spontaneous cardiac baroreflex sensitivity (BRS) in newly diagnosed and never-treated individuals. DESIGN AND PARTICIPANTS: We ...
Furlan Raffaello - - 2005
OBJECTIVE: Fibromyalgia (FM) is a syndrome characterized by widespread musculoskeletal pain. Symptoms of orthostatic intolerance may also be present, suggesting underlying abnormalities of cardiovascular neural regulation. We tested the hypothesis that FM is characterized by sympathetic overactivity and alterations in cardiovascular autonomic response to gravitational stimulus. METHODS: Sixteen patients with ...
Furlan Raffaello - - 2006
Previous reports suggest that inflammatory bowel diseases may be accompanied by abnormalities in the neural autonomic profile. We tested the hypotheses that 1) an exaggerated sympathetic activity characterizes active ulcerative colitis (UC) and 2) a reduction of sympathetic activity by clonidine would be associated with clinical changes of UC. In ...
Tutuncu Neslihan B - - 2005
The present study has been designed to determine melatonin levels in type 2 diabetic patients and test the relationship between the autonomic nervous system and melatonin dynamics. Thirty-six type 2 diabetic patients and 13 age-matched healthy subjects were recruited for the study. Circadian rhythm of melatonin secretion was assessed by ...
Holmberg Björn - - 2005
It is not known whether bilateral stimulation of the subthalamic nucleus, performed to improve skeletal motor control in advanced Parkinson's disease, also affects central autonomic regulation of cardiovascular motor function. Furthermore, reduced treatment with dopaminergic and other drugs after bilateral stimulation of the subthalamic nucleus could affect cardiovascular autonomic reflexes ...
Harada Takuma - - 2005
The effects of drugs on the QT interval should be evaluated precisely in the early stages of drug development because QT prolongation can trigger the so-called torsades de pointes, a life-threatening polymorphic ventricular tachycardia. It has been reported that the QT interval is affected by autonomic nervous tone besides the ...
Yasuda Gen - - 2005
OBJECTIVE: Few studies have assessed whether 24-h blood pressure control induced by antihypertensive agents improves macroalbuminuria in hypertensive type 2 diabetic patients with overt nephropathy. We evaluated the effects of losartan and amlodipine on 24-h blood pressure, autonomic nervous activity, and albuminuria in these patients. RESEARCH DESIGN AND METHODS: In ...
Piccirillo Gianfranco - - 2006
BACKGROUND: Early hypertension is associated with left ventricular diastolic dysfunction due to increased end-diastolic pressure. This increase, through the cardiopulmonary reflexes, can influence autonomic cardiovascular control. METHODS: We assessed autonomic nervous system modulation of cardiovascular signals by power spectral analysis of RR interval and systolic arterial pressure variabilities in subjects ...
Iellamo Ferdinando - - 2005
We tested the hypothesis that individuals with Down syndrome, but without congenital heart disease, exhibit altered autonomic cardiac regulation. Ten subjects with Down syndrome (DS) and ten gender-and age-matched healthy control subjects were studied at rest and during active orthostatism, which induces reciprocal changes in sympathetic and parasympathetic traffic to ...
Gratze Gerfried - - 2005
We hypothesized that the extreme endurance exercise of an Ironman competition would lead to long-standing hemodynamic and autonomic changes. We investigated also the possibility of predicting competition performance from baseline hemodynamic and autonomic parameters. We have investigated 27 male athletes before competition, 1 h after, and then for the following ...
Valipour Arschang - - 2005
To determine the dynamic effects of short-term nasal positive airway pressure (nPAP) on cardiovascular autonomic control, continuous recordings of noninvasively obtained hemodynamic measurements and heart rate variability (HRV) were obtained in 10 healthy subjects during frequency-controlled breathing (between 0.20 and 0.24 Hz) in supine posture under different pressures of nPAP ...
Bilan Andrzej - - 2005
Circadian pattern of heart rate variability spectral indices, including hourly, 24-hour, night, day, morning, and sex-adjusted measures of low frequency (LF), high frequency (HF), and LF/HF, was evaluated in healthy persons in 24-hour 3-lead electrocardiogram. HF showed circadian pattern with the greatest night values and LF/HF with the smallest night ...
Johansson Mats - - 2005
BACKGROUND: Impaired arterial baroreflex function has been associated with an increased risk of ventricular arrhythmia and sudden death. This has also been suggested for patients with chronic renal failure (CRF) who are at high risk for cardiovascular morbidity. The aim of this study was to investigate the arterial baroreflex function ...
Win Ni Ni - - 2005
Heart rate (HR) and arterial blood pressure (BP) changes have been reported during conscious sedation with propofol and midazolam. One potential mechanism to explain these changes is that propofol and midazolam affect HR and BP via changes in the cardiac autonomic nervous system. Two specific hypotheses were tested by HR ...
Yamanaka Nozomu - - 2005
Entropy (ENT) is a newly developed measure of the complexity of heart rate variability (HRV). The aim of this study was to characterize the complexity of HRV in patients with end-stage renal disease (ESRD) and to find a possible clinical utility. Healthy subjects and patients with ESRD undergoing hemodialysis (HD) ...
Shaltout Hossam A - - 2005
A blunted baroreflex sensitivity (BRS), impaired heart rate variability (HRV), and high plasma nonesterified fatty acids (NEFA) are predictors of adverse cardiovascular outcomes. We tested the hypothesis that elevation of NEFA negatively impacts the cardiac baroreflex response and undertook spectral analyses and molecular studies to delineate the mechanism of action. ...
Bertram Delphine - - 2005
The present study examined the effects of baroreceptor loading and unloading on the various rhythms present in the renal sympathetic nerve activity (RSNA) of 10 conscious rats. Short-lasting (4-5 min), steady-state decreases (from -10 to -40 mmHg) and increases (from 5 to 30 mmHg) in arterial pressure (AP) were induced ...
Hanss Robert - - 2005
BACKGROUND: Hypotension due to vasodilation during subarachnoid block (SAB) for elective cesarean delivery may be harmful. Heart rate variability (HRV), reflecting autonomic control, may identify patients at risk of hypotension. METHODS: Retrospectively, HRV was analyzed in 41 patients who were classified into one of three groups depending on the decrease ...
Casu Massimo - - 2005
OBJECTIVE: This study aimed to analyze the autonomic control of heart rate variability (HRV) in subjects receiving chronic l-thyroxine (l-T4) treatment after total thyroidectomy and (131)I therapy for differentiated thyroid carcinoma. METHODS: Blood pressure (BP) and sympatho-vagal activity (evaluated by power spectral analysis (PSA) of time-domain parameters of HRV) were ...
Sanya Emmanuel O - - 2005
Cardiovascular autonomic neuropathy has been previously reported in patients with multiple sclerosis (MS) using standard reflex tests. However, no study has separately evaluated both parasympathetic and sympathetic cardiovascular autonomic regulation. We therefore assessed the baroreflex-mediated vagal and sympathetic control of the heart rate and sympathetic control of the blood vessels ...
Motte Sophie - - 2005
Heart failure is associated with autonomic imbalance, and this can be evaluated by a spectral analysis of heart rate variability. However, the time course of low-frequency (LF) and high-frequency (HF) heart rate variability changes, and their functional correlates during progression of the disease are not exactly known. Progressive heart failure ...
van der Veek Patrick P J - - 2005
Animal studies have demonstrated that visceral afferent stimulation alters autonomic cardiovascular reflexes. This mechanism might play an important role in the pathophysiology of conditions associated with visceral hypersensitivity, such as irritable bowel syndrome (IBS). As such, studies in humans are lacking, we measured viscerosensory-cardiovascular reflex interactions in IBS patients and ...
Campen Matthew J - - 2005
Heart rate variability (HRV) is a well-characterized, noninvasive means of assessing cardiac autonomic nervous system activity. This study examines the basic cardiac responses to hypoxic and hypercapnic challenges in seven strains of commonly used inbred mice (A/J, BALB/cJ, C3H/HeJ, C57BL/6J, CBA/J, DBA/2J, and FVB/J). Adult male mice, 8-12 wk of ...
Prakash E Sankaranarayanan - - 2005
1. In the present study, we tested the hypothesis that heart rate variability (HRV) is reduced in recent-onset hypertension and that pressor responses to standard autonomic reflex tests are not any different in hypertensives compared with normotensives. We also hypothesized that subjects with high-normal blood pressure (BP) would be distinguishable ...
Nacitarhan Vedat - - 2005
The effect of therapeutic ultrasound (US) on nervous system is controversial and the effect on autonomic nervous system is not clear. Therefore, the present placebo-controlled trial was planned to investigate the effects of therapeutic US application on right-side stellate ganglion, by using analysis of heart rate variability (HRV). A total ...
Ozdemir Ozcan - - 2005
Elevated sympathetic nerve activity in patients with mitral stenosis (MS) may be an index of the severity of the disease. Percutaneous mitral balloon commissurotomy (PMBC) is now a standard treatment for many patients with symptomatic MS. We aimed to show the effects of PMBC on autonomic nervous system activity in ...
Chen Shigao - - 2005
The dynamic performance of a new fibre optic sensor intended for measuring physiological fluid pressures is assessed in water. The sensor's sensitivity is evaluated at 23 degrees, 35 degrees and 37 degrees C against a Millar pressure catheter for sinusoidal pressure inputs with frequency ranging from 0.5 to 10 Hz. ...
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 ...
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