Search Results
Results 601 - 650 of 1861
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Lai C J - - 2006
Long-term exposure to intermittent hypoxia (IH), such as that occurring in association with sleep apnea, may result in systemic hypertension; however, the time course changes in arterial pressure, autonomic functions, and baroreflex sensitivity are still unclear. We investigated the changes in cardiovascular neural regulations during the development of chronic IH-induced ...
Wiegerinck Rob F - - 2006
BACKGROUND: Patients with heart failure (HF) have an increased QRS duration, usually attributed to decreased conduction velocity (CV) due to ionic remodeling but which may alternatively result from increased heart size or cellular uncoupling. We investigated the relationship between QRS width, heart size, intercellular coupling, and CV in a rabbit ...
Fu Chin-Hua - - 2006
The incidence of cardiovascular disease is higher in postmenopausal women than in premenopausal women. We hypothesized that long-term vegetarian diets might modulate cardiovascular autonomic functions measured by frequency-domain techniques in healthy postmenopausal women. A total of 35 healthy vegetarians (mean age +/- SEM 55.0 +/- 1.3 years) who had been ...
Freeman Roy - - 2006
Cardiovascular autonomic manifestations of seizures occur frequently in the epileptic population. Common manifestations include alterations in heart rate and rhythm, blood pressure, ECG changes and chest pain. The neuroanatomical and neurophysiological underpinnings of these autonomic manifestations are not been fully elucidated. Diagnostic confusion may arise when ictal symptoms are confined ...
Chern Chang-Ming - - 2006
Baroreflex sensitivity (BRS) and heart rate variability (HRV) are potential therapeutic targets. The present study was conducted to assess changes in BRS and HRV after monotherapy with losartan versus that of atenolol in uncomplicated essential hypertension. Thirty subjects with uncomplicated essential hypertension were randomized to receive atenolol 50 mg to ...
van Orshoven Narender P - - 2006
This study comprises assessment of autonomic function in irritable bowel syndrome (IBS) patients, focusing on meal-related changes. In 18 IBS patients (4 males, mean age 45+/-3.0 [SEM] years) and 19 healthy volunteers (6 males, mean age 41+/-3.5 years) blood pressure, heart rate, heart rate variability and muscle sympathetic nerve activity ...
Samuels E R - - 2006
The noradrenergic locus coeruleus is a major wakefulness-promoting nucleus of the brain, which is also involved in the regulation of autonomic and endocrine functions. The activity of the locus coeruleus is believed to be tonically enhanced by a mesocoerulear dopaminergic pathway arising from the ventral tegmental area of the midbrain. ...
Hsiu H - - 2006
The effects of mechanical stimulation on hemodynamics, such as due to mechanotransduction in vascular endothelial cells, have been widely discussed recently. We previously proposed a resonance model in which the arterial system is treated as a pressure-transmitting system, and suggested that the application of external mechanical stimulation with frequencies near ...
Collins Heidi L - - 2006
The autonomic nervous system modulates cardiac electrophysiology and abnormalities of autonomic function are known to increase the risk of ventricular arrhythmias. The abnormal and unstable autonomic control of the cardiovascular system following spinal cord injury also is well known. For example, individuals with mid-thoracic spinal cord injury have elevated resting ...
Faes Luca - - 2006
A causal approach to the calculation of coherence and transfer function between systolic pressure (SP) and RR interval variability was applied in eight patients and eight control subjects during prolonged tilt test for investigating the impairment of cardiovascular control related to neurally mediated syncope. The causal analysis showed a depressed ...
Hopper James W - - 2006
OBJECTIVE: Evidence of elevated basal heart rate (HR) in posttraumatic stress disorder (PTSD) has been interpreted in terms of elevated sympathetic cardiac activity, as have possible increased cardiovascular disease risks and outcomes associated with elevated HR. Yet it is well-established that the parasympathetic branch of the autonomic nervous system not ...
Hsu Chih-Chieh - - 2006
In this research, heart rate variability (HRV), pulse rate variability (PRV) and human skin conductance (SC) of all acupoints on Heart Meridian were used to evaluate the effects of electrical acupuncture (EA) on acupoint BL15 (Bladder Meridian). Ten healthy volunteers (aged 23 +/- 6) were selected as the control group ...
Wang Gang - - 2006
To investigate the effects of impaired glucose metabolism (IGM) on cardiovascular autonomic nervous systems in essential hypertensive (EH) patients by comparing heart rate variability (HRV) and blood pressure variability (BPV) in EH patients with or without type 2 diabetes mellitus (T2DM). Simultaneous 24-h recordings of ambulatory ECG and blood pressure ...
Princi Tanja - - 2006
Congenital central hypoventilation syndrome (CCHS) is characterised by the failure of the autonomic control of breathing and is defined as a multi-system disorder with symptoms of diffuse autonomic nervous system dysfunction. The present study, considering the heart rate variability (HRV) parameters as expression of cardiac autonomic nervous system activity, reports ...
Baselli Giuseppe - - 2006
Arterial pressure (AP) and heart rate (HR) waves have long been recognized as an important sign of cardiovascular regulation, however, the underlying interactions involving vasomotion, arterial mechanisms and neural regulation have not been clarified. With the aid of simple dynamical models consisting of active peripheral vascular districts (PVDs) fed by ...
Garet Martin - - 2006
In order to examine the acute autonomic response in humans during and immediately after positive pressure-assisted (PPA) breathing, spontaneous cardiac baroreflex (BR) sensitivity was studied through the adaptation of consecutive RR intervals in response to spontaneous systolic blood pressure fluctuations in 11 healthy subjects. The gain (alpha-index) in baroreceptor reflex ...
Sahin Mesut - - 2006
BACKGROUND: Autonomic neuropathy is an important cause of morbidity and mortality in patients with chronic renal failure (CRF) on hemodialysis. Generally, cardiovascular reflex tests are used to determine autonomic neuropathy. Our purpose in this study was to determine the frequency of autonomic neuropathy in patients with CRF on hemodialysis by ...
Platisa Mirjana M - - 2006
Previous results on heart rate variability (HRV) analysis in anorexia nervosa (AN) include some apparently conflicting data. In order to find out the reason for different results and to improve understanding of autonomic control in AN we compare HRV in acute and chronic AN. Spectral powers, fractal scaling exponent and ...
Metsaars Wieneke P WP Department of Obstetrics and Gynaecology, Academic Medical Centre, Amsterdam, The - - 2006
To evaluate whether sympathetic activity is increased in early-onset hypertensive pregnancy and whether this can be influenced by management with plasma volume expansion. The study group consisted of 74 subjects, of which 37 had early-onset hypertensive disorders of pregnancy (preeclampsia or gestational hypertension with fetal growth restriction), who were included ...
Vollebregt Karlijn C KC Department of Obstetrics and Gynaecology, Academical Medical Center, Amsterdam, The Netherlands. - - 2006
The purpose of this study was to evaluate if hemodynamic parameters and sympathetic activity vary between the follicular and luteal phase of the menstrual cycle before using sympathetic activity in pre-pregnancy risk assessment for preeclampsia. We studied 39 healthy women at days 5 to 10 and days 18 to 25 ...
Chaicharn J J Dept. of Biomed. Eng., Univ. of Southern California, Los Angeles, CA, - - 2006
Adults with obstructive sleep apnea syndrome (OSAS) are known to have impaired autonomic function but the corresponding effects in children appear to be more subtle. Model-based analysis of the cardiovascular response to cold face test (CFT) was used to quantify daytime autonomic dysfunction. The increase in transfer gain between respiration ...
Martinmäki Kaisu - - 2006
Conventional spectral analyses of heart rate variability (HRV) have been limited to stationary signals and have not allowed the obtainment of information during transient autonomic cardiac responses. In the present study, we evaluated the ability of the short-time Fourier transform (STFT) method to detect transient changes in vagal effects on ...
Miziara Adriana Nazaré - - 2006
BACKGROUND: Arterial hypertension and Chagas' disease are prevalent pathologies in Latin America. It has been demonstrated that each one of them may cause cardiac autonomic dysfunction. This study aimed to investigate the pattern of cardiac autonomic modulation in chagasic-hypertensive patients. METHODS: Subjects (n=120) without left ventricular dysfunction were distributed in ...
Demirci Mehmet - - 2006
OBJECTIVE: Due to their close proximity to the carotid sinus baroreceptor region, carotid endarterectomy (CEA) and carotid angioplasty/stenting (CAS) carry an inherent risk of affecting baroreflex-mediated regulation of the heart rate. Variations in the heart rate can be studied by measuring heart rate variability (HRV), in which distinct frequency bands ...
Oka Hisayoshi - - 2006
Clinical symptoms of Parkinson's disease (PD) include not only motor distress, but also autonomic dysfunction. To clarify the progression of autonomic nervous dysfunction in PD. The subjects were 44 patients with de novo PD. Autonomic nervous function, including cardiac sympathetic gain, was evaluated on the basis of cardiac radioiodinated metaiodobenzylguanidine ...
Ditor David S - - 2005
Individuals with spinal cord injury (SCI) are prone to orthostatic intolerance and an increased risk of cardiovascular disease. The use of heart rate variability (HRV) and blood pressure variability (BPV) as indices of cardiovascular regulation would be valuable in this population; however, their reproducibility has yet to be tested in ...
Aronow Wilbert S - - 2005
Underlying causes, risk factors, and precipitating causes of heart failure (HF) should be treated. Patients with HF and an abnormal left ventricular ejection fraction (systolic HF) or normal left ventricular ejection fraction (diastolic HF) should be treated with diuretics if fluid retention is present, with an angiotensin-converting enzyme (ACE) inhibitor ...
Mukkamala Ramakrishna - - 2006
Feedback control of total peripheral resistance (TPR) by the arterial and cardiopulmonary baroreflex systems is an important mechanism for short-term blood pressure regulation. Existing methods for measuring this TPR baroreflex mechanism typically aim to quantify only the gain value of one baroreflex system as it operates in open-loop conditions. As ...
Maestri R - - 2005
To assess the accuracy of spectral indices of arterial pressure variability and baroreflex sensitivity obtained from beat-by-beat noninvasive blood pressure recordings by the Finometer device, we compared these measures with those obtained from intra-arterial recordings. The performance of the Finometer was also compared to the traditional Finapres device. In 19 ...
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 ...
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