OBJECTIVE: To investigate carotid atherosclerosis in individuals with masked hypertension (MHT) and white-coat hypertension (WCHT) in a general population. METHODS: Self-measurement of blood pressure at home (HBP) and casual blood pressure (CBP) measurements were recorded in 812 individuals aged at least 55 years (mean 66.4 years) from the general Japanese ...

BACKGROUND: Inappropriate sinus tachycardia (IST) is characterized by heart rate (HR) increase out of proportion to stress level. Radiofrequency (RF) modification of the sinus node (SN) is an accepted treatment modality for medically refractory IST. We describe a new technique using noncontact mapping and a saline irrigated catheter for SN ...

OBJECTIVE: Increased aortic and carotid arterial augmentation index (AI) has been directly linked with cardiovascular disease risk, mortality and morbidity. The aim of this study was to examine whether AI obtained directly from radial artery pressure waveforms (radial AI) can provide information comparable with carotid arterial AI measurements. METHODS: In ...

This study attempted to correlate neurologic changes in awake patients undergoing carotid endarterectomy (CEA) under cervical block anesthesia (CBA) with electroencephalography (EEG) and measurement of carotid artery stump pressure (SP). Continuous EEG and SP monitoring was measured prospectively in 314 consecutive patients undergoing CEA between April 1, 2003, and July ...

The aim of this study was to elucidate the role of the baroreflex in blood pressure control in sloths, Bradypus variegatus, since these animals show labile levels in this parameter. Unanesthetized cannulated sloths were positioned in an experimental chair and the arterial catheter was coupled to a strain gauge pressure ...

Variability of blood pressure is limited by arterial baroreceptors, yet blood pressure still shows circadian changes. This study was undertaken to examine if the responses to the carotid baroreflex also change throughout the day. Responses of cardiac interval (RR), mean arterial pressure (MAP) and vascular resistance (VR) to carotid baroreflex ...

BACKGROUND: Although different populations were examined for the incidence of aspirin resistance, the frequency and related risk factors for aspirin resistance in patients with metabolic syndrome have not been reported yet. This study aimed to determine the frequency of aspirin resistance and its risk factors in patients with metabolic syndrome. ...

Obstructive events during sleep in patients with obstructive sleep apnoea (OSA) cause large alterations in blood pressure, and this may lead to changes in baroreflex function with implications for long-term blood pressure control. This study examined the daytime variations in the responses to carotid baroreceptor stimulation in OSA patients. We ...

BACKGROUND AND PURPOSE: Noninvasive assessment of the hemodynamic significance of carotid stenosis is often performed with MR angiography and supplemented with carotid Doppler sonography. Phase contrast with vastly undersampled isotropic projection reconstruction (PC-VIPR), a novel MR imaging technique, accelerates phase-contrast MR flow imaging and provides both images of the vessels ...

We have previously proposed a technique for estimating the static gain values and impulse response of the arterial and cardiopulmonary total peripheral resistance (TPR) baroreflex by mathematical analysis of beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. In this study, we evaluated the technique with respect to ...

PURPOSE: To evaluate the correlation of stump pressure during balloon occlusion test and relative cerebral blood flow (relative CBF) as measured by 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) after test occlusion. MATERIAL AND METHODS: Balloon occlusion test of the internal carotid artery (ICA) was performed in 25 patients. ...

A large number of patients have hypertension that is resistant to currently available pharmacologic therapy. Electrical stimulation of the carotid sinus baroreflex system has been shown to produce significant chronic blood pressure decreases in animals. The phase II Rheos Feasibility Trial was performed to assess the response of patients with ...

The type and degree of blood pressure changes in cats were studied in acute experiments under conditions of acute hypoxic hypoxia (40% decrease in oxygen partial pressure). During hypoxia, blood pressure increased in cats with pressor type of the carotid sinus reflex and decreased in animals with depressor type of ...

The calculation of impedance for a vascular network is a common method used in circulation studies. Impedance indices (the ratios of the harmonics of pressure to the harmonics of flow) provide the investigator with a measure of the opposition to blood flow in a pulsatile system and are a proven ...

We investigated whether body mass index and blood pressure have an additive influence on the carotid intima-media thickness (IMT). In 27 patients treated for hypertension (47.2+/-8.7 years) and 23 normotensive subjects (44.1+/-8.1 years), 24-h recording of blood pressure was performed. The carotid IMT was determined by ultrasonography and baroreflex sensitivity ...

The purposes of this study were to investigate the effects of circumferential pressure on flexor carpi radialis (FCR) H-reflex in subjects without neuromuscular deficits and to evaluate the skin's contribution to this effect. FCR H-reflex was assessed in 43 subjects by measuring the peak-to-peak amplitude change before, during, and after ...

Hypertension is a major cause of morbidity and mortality worldwide. Despite a myriad of oral agents, many patients fail to reach their target blood pressure. Electrical stimulation of the carotid sinus, an old therapeutic concept, lowers blood pressure by initiating the baroreflex and reducing sympathetic tone. Recent evidence suggests that ...

BACKGROUND: Enhanced external counterpulsation (EECP) is a noninvasive method previously shown to improve measures of myocardial ischemia in patients with coronary artery disease. However, the concomitant effects of EECP on large and small arterial properties have been poorly examined. In a randomized controlled study, we investigated whether arterial stiffness and ...

Prior studies investigating carotid baroreflex control of the cutaneous vasculature have yielded mixed findings. However, previously used methodological and analytical techniques may limit the ability to detect carotid baroreflex-mediated changes in cutaneous vascular conductance (CVC). The aim of this study was to test the hypothesis that dynamic carotid baroreceptor stimulation ...

BACKGROUND: As a sensitive and convenient means for the cerebral hemodynamic monitoring, dynamic cerebral autoregulation testing could be especially useful in medical conditions where less invasive diagnostics and therapies are preferred. This study analysed the effect of carotid stenting on dynamic autoregulation in elderly patients focussing on the relation between ...

Silane (SiH(4)) has been studied in a diamond anvil cell from 7-210 GPa by using optical reflection and absorption techniques at 300 K. The reflectivity and transmission measurements showed a dramatic change in the neighbourhood of 100 GPa. On the basis of reflectivity and absorption experimental data, the pressure dependence of the refractive ...

The aim of this study was to evaluate the cardiovascular response to the activation of arterial chemoreceptors during voluntary apnea in snoring subjects. Fifty five men were enrolled in the study: 33 snorers and 22 non-snorers (control group). The majority of snorers were overweight and hypertensive. The experimental session consisted ...

INTRODUCTION: The push-pull maneuver (PPM) is defined as a reduction in G-tolerance when positive acceleration (+Gz) immediately follows negative acceleration (-Gz) exposure, with the carotid baroreceptors presumably playing a dominant role in the ensuing BP (SBP) responses. The objective of this study was to determine whether application of neck pressure ...

1. In chronic hypertension, the baroreceptors reset to hypertensive levels with a decrease in gain sensitivity, but only a few studies have evaluated baroreceptor resetting during chronic hypotension and, under these conditions, no consistent information is available concerning changes in baroreceptor gain sensitivity. Therefore, in the present study, the aortic ...

INTRODUCTION: Inflammatory markers have been reported to be elevated in hypertension. AIM: We compared levels of inflammatory markers between hypertensives (HT) with target organ damage (TOD) but without associated clinical conditions (ACC), n=55, HT with ACC, n=42, HT without TOD/ACC, n=22 and normotensive controls, n=41. METHODS: Serum levels of CRP, ...

OBJECTIVE: To evaluate the clinical use of radial and carotid artery applanation tonometry as an independent supplement to cuff sphygmomanometry. METHODS: In 44 patients, radial and carotid tonometric pressure recordings were taken at short intervals apart by two persons who had prolonged experience with both. Comparisons were made between directly ...

The piezoelectric properties of a Pb[(Mg(1/3)Nb(2/3))(0.68)]Ti(0.32)O(3) binary system single crystal poled along the [001] direction in the rhombohedral phase were investigated under pressures up to 400 MPa at 25 °C. For the transverse electromechanical property, the difference Δf between the resonance f(r) and antiresonance frequencies f(a), the Δf/f(r) and the electromechanical coupling ...

Using molecular dynamics simulation with the embedded atom method, the structural properties of liquid NiAl in a pressure range of 0-20 GPa are investigated with a quenching rate of 2 K ps(-1). Not only is vitrification of liquid at low temperature detected, but also crystallization by change of average atomic volume as a ...

The characteristics of baroreceptor firing patterns were recognized in experiment, and their dynamics revealed in theoretical analysis. During blood pressure elevation, baroreceptors gradually exhibited bursting, continuous firing, and paradoxical bursting patterns. The bursting was generated through the repeated bifurcations between rest and spiking, the continuous firing was maintained without bifurcation, ...

This study evaluated the compliance and stiffness of decellularized canine common carotid artery as well as decellularized canine ureter and compared it with that of polytetrafluoroethylene, elastin gel combined with polylactic acid tube, and canine common carotid artery. To calculate the compliance and stiffness, internal diameters and cross-sectional areas were ...

Using a mechanical model of the giraffe neck and head circulation consisting of a rigid, ascending, 'carotid' limb, a 'cranial' circulation that could be rigid or collapsible, and a descending, 'jugular' limb that also could be rigid or collapsible, we have analyzed the origin of the high arterial and venous ...

Objective To investigate the role of H(1) and H(2) receptors in the locus ceruleus (LC) in carotid sinus baroreceptor reflex (CSR) resetting induced by intracerebroventricular (i.c.v.) injection of histamine (HA). Methods The left and right carotid sinus regions were isolated from the systemic circulation in 18 male Sprague-Dawley rats anesthetized ...

We investigated carotid baroreflex control of vascular resistance in two groups of high-altitude natives: healthy subjects (HA) and a group with chronic mountain sickness (CMS), a maladaptation condition characterized by high haematocrit values and symptoms attributable to chronic hypoxia. Eleven HA controls and 11 CMS patients underwent baroreflex testing, using ...

The influence of the carotid-cardiac baroreflex on blood pressure regulation was evaluated during supine rest and 40 degrees head-up tilt (HUT) in 9 healthy young subjects with and without full cardiac vagal blockade. The carotid baroreflex responsiveness, or maximal gain (G(MAX)), was assessed from the beat-to-beat changes in heart rate ...

A little more than three decades ago, there was little doubt that baroreceptors were crucial for both the short-term and long-term control of mean arterial blood pressure (MAP). Then, in 1970 it was reported that baroreceptors reset completely within 48 hours in hypertensive rats. Three years later, it was reported ...

The arterial baroreceptors and their afferent fibres provide the sensory arm of the reflex that regulates systemic arterial pressure. We have examined whether the relationship between mean baroreceptor discharge and mean arterial pressure is altered when heart rate changes. Experiments were performed on pentobarbitone-anaesthetized rabbits. We recorded the activity of ...

To determine whether carotid intima media thickness is increased in children with primary hypertension, the current study compared carotid intima media thickness in hypertensive children with that of normotensive control subjects matched closely for body mass index and determined the relationship between carotid intima media thickness and hypertension severity determined ...

PATIENTS AND METHODS: We studied 16 healthy smokers and 16 nonsmokers acting as controls. We subjected smokers and nonsmokers to cardiopulmonary baroreceptor stimulation by studying forearm and common carotid haemodynamic and sympathovagal balance. Smokers repeated the tests after smoking one cigarette. Smokers and controls were subjected to passive elevation of ...

The objective of the present report was to present a modification of the standard sinus lift procedure. The modification consists of the creation of a mechanism facilitating maxillary sinus mucosa lift by means of negative pressure and simplification of the instrumentation used for this procedure. With the change in technique, ...

It has been suggested that resistance training (RT) increases arterial stiffness. The purpose of the present study was to clarify the effect of eccentric RT (ERT) and concentric RT (CRT) on arterial stiffness in female adults by an interventional study. In total, 29 healthy female subjects were randomly assigned to ...

Carotid artery intima-media thickness (IMT) is a widely accepted index for assessing atherosclerosis, and is known to be a risk indicator for cardiovascular and cerebrovascular events. Oxidative stress and inflammation are also known to play critical roles in the pathogenesis of vascular events. We studied the association between IMT and ...

BACKGROUND: Damage in large arteries, characterized by increased intima-media thickness and decreased compliance, is frequent in hemodialysis patients and increases cardiovascular morbidity and mortality. Since volume overload and hypertension may accelerate atherosclerosis in patients with chronic renal failure, the aim of this 1-year study was to assess whether strict volume ...

Baroreceptor cardiac reflex sensitivity is reduced in hypertension and is considered a powerful prognostic factor in cardiovascular health. This study analyzes the acute effects of a brief respiratory training on baroreceptor sensitivity and on two new proposed baroreflex parameters: baroreceptor power (i.e., the percentage of cardiac beats regulated by the ...

X-ray diffraction and Raman scattering studies on the scheelite structured barium molybdate show that, at ∼5.8 GPa, it undergoes a first order phase transition to the fergusonite structure (I 2/a,Z = 4)-as also observed in iso-structural barium tungstate. At still higher pressures, barium molybdate transforms to another phase between ∼7.2 and ...

Systemic hypotension has been observed for up to 36 hours in response to stimulation of the carotid baroreceptor by carotid angioplasty and stenting (CAS). The aim of this study was to identify risk factors and cardiac outcomes for postprocedural hypotension requiring vasopressor support after CAS. Between 2003 and 2005, 143 ...

BACKGROUND: Carotid sinus hypersensitivity is the most commonly reported cause of falls and syncope in older persons. Recent guidelines recommend 5 to 10 seconds of carotid sinus massage in supine and upright positions with beat-to-beat monitoring. The aim of this study was to determine the prevalence of carotid sinus hypersensitivity ...

OBJECTIVE: Hemodynamic instability (hypertension, hypotension and bradycardia) is a well-known complication of carotid endarterectomy. Carotid angioplasty and stenting (CAS) is becoming a valuable alternative treatment for patients with severe carotid stenosis and increased surgical risk. CAS implies instrumentation of the carotid bulb, so baroceptor dysfunction may provoke hemodynamic instability. The ...

Baroreceptor cardiac reflex sensitivity is reduced in hypertension and is considered a powerful prognostic factor in cardiovascular health. This study analyzes the acute effects of a brief respiratory training on baroreceptor sensitivity and on two new proposed baroreflex parameters: baroreceptor power (i.e., the percentage of cardiac beats regulated by the ...

OBJECTIVE: To assess the prevalence of aortic root dilatation in a large cohort of uncomplicated hypertensive patients and to evaluate the relations of aortic root size to different markers of cardiac and extracardiac target organ damage (TOD). METHODS: A total of 3366 untreated and treated essential hypertensive patients (mean age, ...

Although electroacupuncture reduces sympathetic nerve activity (SNA) and arterial pressure (AP), the effects of electroacupuncture on the arterial baroreflex remain to be systematically analyzed. We investigated the effects of electroacupuncture of Zusanli on the arterial baroreflex using an equilibrium diagram comprised of neural and peripheral arcs. In anesthetized, vagotomized, and ...