Search Results
Results 451 - 500 of 1844
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Claydon Victoria E - - 2008
Spinal cord injury (SCI) has profound effects on cardiovascular autonomic function due to injury to descending autonomic pathways, and cardiovascular diseases are the leading causes of morbidity and mortality after SCI. Evaluation of cardiovascular autonomic dysfunction after SCI and appraisal of simple noninvasive autonomic assessments that are clinically meaningful would ...
Stemper B - - 2008
OBJECTIVE: To evaluate the impact of vagus nerve stimulation (VNS) on heart rate and blood pressure (BP) modulation in epilepsy patients. MATERIAL AND METHODS: Twenty-one epilepsy patients with VNS were tested during on (60 s) and off (5 min) phases. We monitored BP, RR intervals (RRI) and respiration. Spectral analysis ...
Chen Xiaoxiao - - 2008
Heart rate (HR) power spectral indexes are limited as measures of the cardiac autonomic nervous systems (CANS) in that they neither offer an effective marker of the beta-sympathetic nervous system (SNS) due to its overlap with the parasympathetic nervous system (PNS) in the low-frequency (LF) band nor afford specific measures ...
Laude Dominique - - 2008
Short-term blood pressure (BP) variability is limited by the arterial baroreflex. Methods for measuring the spontaneous baroreflex sensitivity (BRS) aim to quantify the gain of the transfer function between BP and pulse interval (PI) or the slope of the linear relationship between parallel BP and PI changes. These frequency-domain (spectral) ...
Chen Xiaoxiao - - 2008
We previously developed a mathematical analysis technique for estimating the static gain values of the arterial total peripheral resistance (TPR) baroreflex (G(A)) and the cardiopulmonary TPR baroreflex (G(C)) from small, spontaneous beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. Here, we extended the mathematical analysis so as ...
Huang Chih-Cheng - - 2007
The baroreflex maintains a stable blood pressure (BP) by dynamically adjusting heart rate (vagal component) and total peripheral resistance (adrenergic component). Vagal baroreflex sensitivity (BRS-v) is widely used but no methodology existed to quantitate adrenergic baroreflex sensitivity (BRS-a) until we developed the indices of BP recovery time (PRT) and BRS-a. ...
Hanss R - - 2007
BACKGROUND: To investigate if changes in low-to-high frequency ratio (LF/HF), low frequency (LF) and high frequency (HF) heart rate variability reflect autonomic regulation during spinal anaesthesia (SA) in pregnant women scheduled for elective Caesarean section. METHODS: Prospective clinical trial. Systolic blood pressure (SBP) and heart rate variability were analysed at ...
Catz A - - 2007
OBJECTIVE: Study hemodynamic responses to cold application to the foot (CAF) to explore the autonomic cardiovascular control by the spinal cord. DESIGN: Controlled experimental study. Hemodynamic variables were measured or calculated for 13 healthy subjects, 10 patients with traumatic T4-T6 paraplegia, and 11 patients with traumatic C4-C7 tetraplegia. Subjects were ...
Vorluni L - - 2008
AIM: This study evaluated the influence of muscle mechanical afferent stimulation on the integrated arterial baroreflex control of the sinus node during dynamic exercise. METHODS: Systolic blood pressure (SBP) and pulse interval (PI) were measured continuously and non-invasively in 15 subjects at rest and during passive cycling. The arterial baroreflex ...
Umeno Katsumi K System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, - - 2008
Relationships between smell sensation and autonomic changes have been studied extensively. However, the possibility that odorants may also act on the lung and lower airway remains unknown. The present results provide the first evidence that the lung and lower airway exert an inhibitory influence on the cardiovascular system in response ...
Maser Raelene E - - 2008
BACKGROUND: Sleep-disordered breathing (SDB) is an independent risk factor for cardiovascular morbidity. Dysfunction of the cardiovascular autonomic nervous system may be a potential mechanism whereby SDB is linked to cardiovascular disease. Repetitive sympathetic activation during apneic episodes may impair cardiovascular reflex function, and increased sympathetic activity can stimulate renin release. ...
Oka H - - 2007
OBJECTIVE: To examine the relation between the results of cardiac (123)I-meta-iodobenzylguanidine (MIBG) scintigraphy and cardiovascular autonomic function in Lewy body disease (LBD). METHODS: The subjects were 66 patients with LBD, 44 of whom had Parkinson disease (PD), 10 PD with dementia (PDD), and 12 dementia with Lewy bodies (DLB); 20 ...
Zhu Heng - - 2007
To better understand the mechanisms of tear drainage, the mechanical properties of porcine canaliculus were measured in compression mode while submerged in isotonic fluid by using a dynamic mechanical analyzer. The storage modulus (E') for the porcine canaliculus is about 3 kPa at 1 Hz and increases to about 5 ...
de Souza Neto Edmundo Pereira - - 2007
Heart beat rate and blood pressure, together with baroreflex sensitivity, have become important tools in assessing cardiac autonomic system control and in studying sympathovagal balance. These analyses are usually performed thanks to spectral indices computed from standard spectral analysis techniques. However, standard spectral analysis and its corresponding rigid band-pass filter ...
Birch Anthony A - - 2007
OBJECTIVES: The objective of this work was to test the hypothesis that the Finapres underestimates blood pressure during sympathetic peripheral vasoconstriction. METHODS: Measurements were made simultaneously with two Finapres devices and one radial artery tonometer during the onset of periodic lower body negative pressure in healthy volunteers. The Finapres is ...
Duschek Stefan - - 2007
The cardiac baroreflex constitutes an important mechanism mediating autonomic control of heart activity. Its function can be quantified by applying sequence analysis based on continuous recordings of blood pressure and heart rate. In this study, several indices derived from this method were compared regarding their suitability to estimate baroreflex function ...
Verheyden B - - 2007
AIM: Astronauts commonly return from space with altered short-term cardiovascular dynamics and blunted baroreflex sensitivity. Although many studies have addressed this issue, post-flight effects on the dynamic circulatory control remain incompletely understood. It is not clear how long the cardiovascular system needs to recover from spaceflight as most post-flight investigations ...
Passino Claudio - - 2007
OBJECTIVE: To assess the effects of acute exposure to simulated high altitude on baroreflex control of mean cerebral blood flow velocity (MCFV). PATIENTS AND METHODS: We compared beat-to-beat changes in RR interval, arterial blood pressure, mean MCFV (by transcranial Doppler velocimetry in the middle cerebral artery), end-tidal CO2, oxygen saturation ...
Fujiwara Y - - 2007
BACKGROUND: The objective of this study was to determine whether pre-operative heart rate variability (HRV) estimated using the newly developed MemCalc method predicts hypotension after spinal anaesthesia (SA). METHOD: Fifty-two patients with American Society of Anesthesiologists physical status I or II, aged 38-84 years, scheduled to undergo elective transurethral surgery ...
Tanaka Kazuhiko - - 2007
Heart failure (HF) commonly results in atrial fibrillation (AF) and fibrosis, but how the distribution of fibrosis impacts AF dynamics has not been studied. HF was induced in sheep by ventricular tachypacing (220 bpm, 6 to 7 weeks). Optical mapping (Di-4-ANEPPS, 300 frames/sec) of the posterior left atrial (PLA) endocardium ...
Tanakaya Machiko - - 2007
Postprandial hypotension is an important hemodynamic abnormality in diabetes mellitus, but few reports are available on the relationship between autonomic dysfunction and postprandial hypotension. Ten diabetic patients and 10 healthy volunteers were recruited for this study. Postural blood pressure and heart rate changes were measured before lunch, and then the ...
Kurosawa Tomoko - - 2007
An association between ambient air pollution and reduced cardiac autonomic function assessed by heart rate variability (HRV) mainly in elderly persons has been suggested by a number of epidemiological studies, but the link between the HRV and pulmonary function in humans remains unknown although such air pollution should primarily affect ...
Mourot Laurent - - 2007
The present study was aimed at investigating the autonomic nervous system influences on the fractal organization of human heart rate during sympathovagal interactions, with special emphasize on the short-term fractal organization in heart rate variability (HRV), as assessed by the scaling exponent (alpha(1)) of the detrended fluctuation analysis. Linear and ...
Studinger Péter - - 2007
According to conventional wisdom, hysteresis in cardiac vagal baroreflex function exhibits a specific pattern: pressure falls are associated with longer heart periods and a smaller linear gain. A similar pattern occurs in the pressure-diameter relationship of barosensory vessels, and therefore it has been suggested that baroreflex hysteresis derives solely from ...
Mandl Thomas - - 2007
OBJECTIVE: Exocrine function always is and autonomic nervous function may be impaired in primary Sjögren's syndrome (pSS). Since autonomic nervous signaling is a prerequisite for exocrine secretion we wanted to assess autonomic nervous function in pSS and relate it to diagnostic measures of exocrine function. METHODS: Autonomic nervous function was ...
Jin Yu - - 2008
To evaluate whether neuropathic pain affects autonomic nervous activities, we investigated daily change in cardiovascular parameters and plasma norepinephrine (NE) in free-moving rats after chronic constriction injury (CCI) on the sciatic nerve. Arterial blood pressure (BP), heart rate (HR), and the power spectrum of pulse interval variability were analyzed. Daily ...
Biaggioni Italo - - 2007
Patients with autonomic failure provide a unique opportunity to study the role of sympathetic function on the regulation of blood volume. These patients have a reversal of the normal diurnal variation in urine output and have twice as much natriuresis during the night. Autonomic failure patients are also unable to ...
Zöllei Eva - - 2007
The aim of this study was to assess the influence of breathing pattern on the reproducibility of the most commonly used heart rate and blood pressure variability parameters and baroreflex indices. 5-5 min ECG and blood pressure recordings were made and repeated for 10 healthy volunteers in supine rest on ...
Dabisch Paul A - - 2007
Several studies in conscious animals have reported parasympathetic dysfunction in the eyes following exposure to cholinesterase inhibitors. Given the similarities between the autonomic innervation in the eye and the heart, it is possible that parasympathetic dysfunction could also occur in the heart. Therefore, the present study assessed time domain indices ...
Melo R C - - 2008
BACKGROUND: Evaluation of non-pharmacological therapies that improve autonomic control of the heart rate in older subjects has a clinical significance, because reduced heart rate variability (HRV) can be associated with higher cardiovascular morbidity and mortality rates. OBJECTIVE: To investigate if strength training improves cardiac autonomic control in healthy older men. ...
Bissonnette John M - - 2007
Methyl-CpG-binding protein 2 is a transcription factor that is involved in gene silencing. It is mutated in the majority of cases of Rett syndrome. This X-linked neurodevelopmental disorder is reported to involve abnormalities in autonomic cardiovascular regulation. As an initial step in understanding the basis for these abnormalities we have ...
Yilmaz Ugur - - 2007
PURPOSE: We investigated the role of the autonomic nervous system in the chronic pelvic pain syndrome by studying blood pressure changes, power spectral analysis of heart rate variability, and hand and foot sympathetic skin responses in men with the chronic pelvic pain syndrome and healthy controls. MATERIALS AND METHODS: We ...
Diedrich André - - 2007
BACKGROUND: Children with Congenital Central Hypoventilation Syndrome (CCHS) typically present as newborns with alveolar hypoventilation. With the advent of genetic testing, parents of affected children and other unrelated adults, all heterozygous for the disease-defining PHOX2B polyalanine expansion mutation with the 20/25 genotype, are being identified in adulthood. Though children with ...
Hesse Christiane - - 2007
Patients with hypertension have a blunted sensitivity of baroreflex control of heart period. In these patients, baroreflex sensitivity is positively related to heart rate variability and inversely related to blood pressure variability. We hypothesized that this relationship would also be evident in healthy normotensive subjects and that individuals with higher ...
Batchinsky Andriy I - - 2007
INTRODUCTION: In this study we explored direct and indirect measures of autonomic nervous system function, as well as changes in cardiovascular complexity, during hemorrhagic shock (HS). METHODS: HS was induced in anesthetized sheep (n=8) by removing 40 ml/kg of blood in four 10 ml/kg steps over 40 min. Resuscitation was ...
Fukuta Hidekatsu - - 2007
Nearly half of patients with heart failure (HF) have a normal ejection fraction (EF) and have been labeled as having diastolic HF. Diastolic HF is characterized by a normal EF, a variable amount of concentric left ventricular hypertrophy, and abnormal diastolic function. Differentiating diastolic HF from HF with a reduced ...
Flachenecker Peter - - 2007
This review gives an overview of autonomic dysfunction encountered in Guillain-Barré syndrome (GBS) and multiple sclerosis (MS). In GBS, cardiovascular dysregulation is common and may lead to serious bradyarrhythmias that need to be recognised for the early initiation of appropriate therapy. Although standardised autonomic tests were useful for the diagnosis ...
Murialdo G - - 2007
Changes in body composition, hormone secretions, and heart function with increased risk of sudden death occur in eating disorders. In this observational clinical study, we evaluated sympathovagal modulation of heart rate variability (HRV) and cardiovascular changes in response to lying-to-standing in patients with anorexia (AN) or bulimia nervosa (BN) to ...
Ducla-Soares J L - - 2007
Non-invasive autonomic evaluation has used fast Fourier transform (FFT) to assign a range of low (LF) and high frequencies (HF) as markers of sympathetic and parasympathetic influences, respectively. However, FFT cannot be applied to brief transient phenomena, such as those observed on performing autonomic tests where the acute changes of ...
Stauss Harald M - - 2007
1. Blood pressure and organ perfusion are controlled by a variety of cardiovascular control systems, such as the baroreceptor reflex and the renin-angiotensin system (RAS), and by local vascular mechanisms, such as shear stress-induced release of nitric oxide (NO) from the endothelium and the myogenic vascular response. Deviations in arterial ...
Genovesi Simonetta - - 2007
BACKGROUND: The aim of our study was to evaluate whether convective (haemofiltration, Hf) and diffusive (haemodialysis, Hd) dialysis techniques induce different patterns of long- and short-term autonomic adjustments in haemodynamically stable dialysis patients. METHODS: Ten haemodynamically stable Hd patients were studied. Each patient underwent a block of six Hd sessions, ...
Seydnejad Saeid - - 2007
A novel approach for detection of polynomial nonlinearity in the neuro-cardiovascular system based on cyclostationary analysis is presented. Metronome breathing is employed to provide a sinusoidal input to the neuro-cardiovascular system in which Heart Rate Variability (HRV) and Blood Pressure Variation (BPV) are considered as its outputs. The presence of ...
Ludwig Janne - - 2007
Dysfunctions of the autonomic nervous system (ANS) are common in Parkinson's disease (PD). Regarding motor disability, deep brain stimulation of the subthalamic nucleus (STN) is an effective treatment option in long lasting PD. The aims of this study were to examine whether STN stimulation has an influence on functions of ...
Tsunetsugu Yuko - - 2007
The physiological effects of "Shinrin-yoku" (taking in the atmosphere of the forest) were examined by investigating blood pressure, pulse rate, heart rate variability (HRV), salivary cortisol concentration, and immunoglobulin A concentration in saliva. Subjective feelings of being "comfortable", "calm", and "refreshed" were also assessed by questionnaire. The subjects were 12 ...
Schrezenmaier Christine - - 2007
BACKGROUND: The baroreflex is responsible for maintaining a stable blood pressure (BP) despite changes in body positions and fails in many autonomic disorders. The baroreflex regulates BP by changing the heart rate (vagal component) and total peripheral resistance (adrenergic component). Baroreflex sensitivity is widely used to quantify the vagal component ...
Glos Martin - - 2007
To determine the short-term effects of non-invasive positive pressure ventilation (PPV) on spontaneous baroreflex sensitivity, we acquired time series of RR interval and beat-to-beat blood pressure in 55 healthy volunteers (mean age 46.5+/-10.5 years), who performed breathing tests on four occasions at frequencies of 12 and 15/min, with application of ...
Fukuno Hiroshi - - 2007
OBJECTIVE: Percutaneous treatment of hepatocellular carcinoma (HCC) located directly under the diaphragm is problematic because ultrasonic imaging is difficult, and the lung may be injured during the procedure. It has been reported that an infusion of 5% glucose solution into the thoracic cavity enables percutaneous treatment in such cases. However, ...
Jones Alexander A Medical Research Council Epidemiology Resource Centre, University of Southampton, Southampton, United - - 2007
Small size at birth is associated with exaggerated blood pressure responses to psychological stressors, which increase the risk of developing sustained hypertension in adult life. Explanatory mechanisms for this association are not well characterized. We investigated the hypothesis that an adverse fetal environment, reflected by small size at birth, persistently ...
Schmidt Hendrik - - 2007
Decreased heart rate variability (HRV) in critically ill patients indicates a poor prognosis. In heart failure patients, there is an elevated sympathetic tone, reflected by a dominance of sympathetic parameters in HRV, whereas in critically ill patients sympathetic and parasympathetic modulation of heart rate is attenuated despite increased catecholamine blood ...
Tong Yan-Qing - - 2007
OBJECTIVE: We attempt to identify heart rate variability (HRV) components and decide whether or not such components are more sensitive to the hemodialysis (HD) process by excluding the presence of comorbid conditions known to affect HRV. METHODS: It was a prospective cohort study of factors associated with HRV. Thirty-five HD ...
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