Search Results
Results 301 - 350 of 1761
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Graham Michael R - - 2008
Blood pressure (BP) measurements provide information regarding risk factors associated with cardiovascular disease, but only in a specific artery. Arterial stiffness (AS) can be determined by measurement of arterial pulse wave velocity (APWV). Separate from any role as a surrogate marker, AS is an important determinant of pulse pressure, left ...
Painter Page R - - 2008
The arterial pulse is a viscous-fluid shock wave that is initiated by blood ejected from the heart. This wave travels away from the heart at a speed termed the pulse wave velocity (PWV). The PWV increases during the course of a number of diseases, and this increase is often attributed ...
Reddy Anilkumar K AK Sections of Cardiovascular Sciences&Geriatrics, Dept. of Medicine, Baylor College of Medicine, Houston, TX 77030, USA. - - 2008
The Little dwarf mouse lives 30% longer than its age-matched wild-type (WT) mouse. We determined aortic input impedance in 21 (8 Little, 13 WT) 4 month-old mice. Modulus of impedance was calculated from the Fourier transformed aortic pressure (P) and average luminal flow velocity (V(avg)) as |Z(i)| = |P|/|V(avg)|. Characteristic ...
Sola Josep J Swiss Center for Electronics and Microtechnology (CSEM), 2002 Neuchâtel, Switzerland. - - 2008
The continuous separate monitoring of cardiac and vascular functions provide important insights on cardiovascular regulation. In the last years several attempts have failed at demonstrating the feasibility of using Pulse Wave Velocity as a surrogate indicator of arterial blood pressure. Upon the hypothesis that the cause of PWV unreliability is ...
Leung Mande T MT Department of Electrical and Computer Engineering, the University of British Columbia, Vancouver, - - 2008
A novel method to obtain the aortic pressure waveform using a sequence of B-mode images is developed in this project. An automatic edge detection algorithm is applied to a sequence of longitudinal images of the aortic arch acquired from a suprasternal view. The aortic distension waveform is obtained by measuring ...
Hahn Jin-Oh JO Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. - - 2008
This paper presents a new system identification approach to the reconstruction of central aortic blood pressure signal by exploiting a non-invasive peripheral blood pressure measurement. This technique, which is called the 'adaptive' transfer function, is able to reconstruct the aortic blood pressure signal by characterizing the aortic-to-peripheral cardiovascular dynamics solely ...
Swamy Gokul G Department of Electrical and Computer Engineering, East Lansing, MI 48824, USA. - - 2008
We developed a new technique to estimate the aortic pressure (AP) waveform from a single peripheral artery pressure (PAP) waveform. The technique 1) employs a parallel tube model of the arterial tree to establish a transfer function relating PAP to AP with unknown parameters; 2) estimates the parameters from the ...
Agarwal Rajiv - - 2008
Besides an overall increase in blood pressure, hemodialysis patients have marked disturbance in interdialytic ambulatory blood pressure pattern that is characterized by blunted circadian amplitude and a steady rise in blood pressure between dialysis treatments. The pathophysiology of this abnormal blood pressure profile is poorly understood. We hypothesized that the ...
Simonetti Giacomo D - - 2008
In adults the contour analysis of peripheral pressure waves in the upper limb reflects central aortic stiffness. Here, we wanted to demonstrate the appropriateness of pulse contour analysis to assess large artery stiffness in children. Digital volume pulse analysis, with the computation of the stiffness index and pulse wave velocity ...
Akhila Tadinada
We propose to develop a blood pressure (BP) monitoring system which can be used for continuous ambulatory blood pressure measurement. The system will be used to measure blood pressure cycles for a person by recording a person’s blood pressure 24 hours a day for 7 days. Blood pressure cycles give ...
Edwards David G - - 2008
We determined the effects of static and dynamic muscle contraction at equivalent workloads on central aortic pressure and wave reflection. At random, 14 healthy men and women (23 +/- 5 yr of age) performed a static handgrip forearm contraction [90 s at 30% of maximal voluntary contraction (MVC)], dynamic handgrip ...
Frey Bernhard - - 2008
OBJECTIVE: The photoplethysmographic wave is displayed by most pulse oximeters. It may be used as a non-invasive alternative to invasive arterial blood pressure trace analysis for continuous haemodynamic monitoring in selected situations. PATIENTS AND SETTING: Four cardiac patients treated in a tertiary neonatal-paediatric intensive care unit. MEASUREMENTS: Simultaneous monitoring of ...
Mitchell Gary F - - 2008
Systolic hypertension is associated with increased pulse pressure (PP) and increased risk for adverse cardiovascular outcomes. However the pathogenesis of increased PP remains controversial. One hypothesis suggests that aortic dilatation, wall stiffening and increased pulse wave velocity result from elastin fragmentation, leading to a premature reflected pressure wave that contributes ...
Lydakis Charalampos - - 2008
The aim of this investigation was to determine the acute effects of isometric fatiguing handgrip (IFHG) and lower body negative pressure (LBNP) on indices of central arterial stiffness. Thirteen subjects were studied. Renal blood velocity (Duplex Ultrasound) and blood pressure (Finapres) were monitored during IFHG and LBNP at -30 and ...
Li John K-J - - 2007
Isolated systolic hypertension (ISH) is prevalent in the elderly and the contributing factors are predominantly vascular in origin. We previously showed that the hemodynamic manifestation of ISH is the result of a concurrently mild increase in peripheral resistance with a large reduction in arterial compliance or greatly increased vascular stiffness. ...
Podolec Piotr - - 2007
The objectives of this study were to determine the relationship between carotid-femoral (cfPWV) and aortic pulse wave velocity (aPWV) and to compare their modulators and association with coronary artery disease (CAD). We studied 107 consecutive patients (68 men) with a mean age of 60.49+/-8.31 years who had stable angina and ...
Perlstein Todd - - 2007
Pulse pressure increases with age in industrialized societies as a manifestation of arterial stiffening. Lead accumulates in the vasculature and is associated with vascular oxidative stress, which can promote functional and structural vascular disease. We tested the hypothesis that cumulative community-level lead exposure, measured with K-X-ray fluorescence, is associated with ...
Kim Kyung Taec - - 2007
Self-compression of attosecond high-order harmonic pulses in the harmonic generation medium itself has been demonstrated. The attosecond pulses were generated in an argon-filled gas cell and compressed by exploiting the dispersion characteristics of argon. Since the harmonic generation medium itself was used as the compression medium, continuous chirp control was ...
Jiang Benyu - - 2008
Pulse wave velocity (PWV), the speed of propagation of arterial pressure waves through the arterial tree, is related to arterial stiffness and is an important prognostic marker for cardiovascular events. In clinical practice PWV is commonly determined by arterial tonometry, with a noninvasive pressure sensor applied sequentially over carotid and ...
Ahlund Catherine - - 2008
OBJECTIVES: Analysis of the contour of the arterial pressure pulse (pulse wave analysis; PWA) adds information about arterial stiffness etc., beyond that obtained from absolute pressures. Peripheral pulses normally show an anterograde systolic peak and two reflected peaks: one in systole and one in diastole. The amplitudes and timings of ...
Penny Daniel J - - 2008
This study undertook a detailed examination of the ventricular-vascular interaction of the predominant beta-adrenergic agonist dobutamine using wave intensity analysis. Eight anesthetized open-chest ewes were instrumented with an aortic micromanometer to measure central aortic blood pressure (P) and an ultrasonic flow probe to obtain ascending aortic blood velocity (U). Hemodynamics ...
Munir Shahzad - - 2008
Peripheral systolic blood pressure is amplified above central aortic systolic pressure, but the late systolic shoulder of the peripheral pulse may approximate central systolic pressure. Because late systolic pressure also determines the peripheral augmentation index, a measure of pressure wave reflection within the systemic circulation, this implies a direct relationship ...
Vergnaud Anne Claire - - 2008
BACKGROUND: Body mass index (BMI) and waist circumference (WC) are increased in subjects chronically treated for hypertension. However, the relationships of BMI, WC and metabolic syndrome (MS) with central wave reflections and pulse pressure (PP) amplification have never been investigated. METHODS: A cohort of 517 treated hypertensives was studied cross-sectionally ...
Wasserthal Lutz T - - 2007
Heartbeat activity in tethered adult drosophilids was recorded using a linear optosensor chip and an IR-light beam. Recording from two to five sensor elements within 250 mum along the anterior heart, it was possible to analyze periodic reversals. In intact Drosophila melanogaster and D. hydei, longer anterograde pulse periods with ...
O'Rourke Michael F - - 2007
In the nineteenth century, prior to the introduction of the cuff sphygmomanometer, arteriosclerosis (stiffening of arteries) was recognized by clinicians and by life insurance companies as an indicator of vascular aging and cardiovascular risk, even in asymptomatic individuals. Through the twentieth century, views on aging came to focus on values ...
Song Sang Heon - - 2007
BACKGROUND: It has been recently suggested that gamma-glutamyltransferase (GGT) is independently associated with cardiovascular mortality and atherosclerosis, so the present study evaluated whether GGT is an additional marker of arterial stiffness, independent of other risk factors, in screening cohorts. METHODS AND RESULTS: The 1,387 individuals (741 men, 646 women) who ...
Raamat Rein - - 2007
Digital pulse volume and arterial compliance have been estimated by using the finger arterial pressure and volume waveforms when performing measurements at rest and during local cold exposure in 17 volunteers. The amplitude-based algorithm determines compliance as a ratio of finger volume and pressure pulses. Cooling was conducted by immersion ...
Bia D - - 2008
AIMS: The intra-aortic balloon pumping (IABP) changes pressure and increases the aorta shear stress reversal (SS(R)) and oscillatory (SS(O)) components. Hence, IABP-dependent changes in aortic biomechanics would be expected, because of vascular smooth muscle (VSM) tone (i.e. flow-induced endothelium-dependent response, related to SS(R) and SS(O) variations) and/or pressure changes. To ...
Philips Jean-Christophe - - 2008
OBJECTIVE: To evaluate pulse pressure changes according to duration of type 1 diabetes and to assess the influence of posture. RESEARCH DESIGN AND METHODS: We performed continuous measurement of blood pressure with a Finapres device during a 3 x 1 min posture test (standing, squatting, standing) in 159 type 1 ...
Schutte R - - 2008
OBJECTIVES: Few studies have addressed the effect of cadmium toxicity on arterial properties. METHODS: We investigated the possible association of 24 h urinary cadmium excretion (an index of lifetime exposure) with measures of arterial function in a randomly selected population sample (n = 557) from two rural areas with low ...
Casey Darren P - - 2007
Endurance exercise is efficacious in reducing arterial stiffness. However, the effect of resistance training (RT) on arterial stiffening is controversial. High-intensity, high-volume RT has been shown to increase arterial stiffness in young adults. We tested the hypothesis that an RT protocol consisting of progressively higher intensity without concurrent increases in ...
Vlachopoulos Charalambos - - 2007
INTRODUCTION: Increased levels of fibrinogen have been related to target organ damage and cardiovascular outcomes. Arterial elastic properties are important determinants of cardiovascular performance and predictors of the corresponding risk. This study investigated whether the fibrinogen level is associated with arterial stiffness and wave reflections. METHODS: We studied 229 consecutive, ...
Wykretowicz Andrzej - - 2007
1. Obesity appears to influence vascular stiffness, an important cardiovascular risk factor. An accurate picture of arterial stiffness may be obtained when a combination of various techniques is used. 2. The purpose of the present study was to assess whether the body mass index (BMI) and body fat content obtained ...
Afshari R - - 2007
BACKGROUND: Opioid overdose is an increasing health problem worldwide. The cardiovascular toxicity of opioids contributes to morbidity and mortality in overdose but the hemodynamic effects of opioids reported in animal and human studies are contradictory. METHODS: We performed a prospective observational study of patients admitted to hospital following an overdose ...
Borlaug Barry A - - 2007
OBJECTIVES: The aim of this study was to examine the relationship between individual components of left ventricular (LV) afterload and tissue Doppler echocardiography (TDE) velocities in humans. BACKGROUND: Acute increases in afterload slow diastolic relaxation as assessed invasively, yet little is known about chronic effects of load and loading sequence ...
Zheng Dingchang - - 2007
Arterial volume compliance reduces with age and with arterial disease and its easy non-invasive measurement will be of significant clinical value in monitoring the development of cardiovascular disease or evaluating therapy. However, the relationship between arterial volume compliance and pressure is not fully understood. To enable us to examine changing ...
Biwa Shiro - - 2007
This paper describes ultrasonic measurements of normal and tangential stiffnesses of the contacting interface between polished aluminum blocks subjected to nominal contact pressures up to about 3.8 MPa. These stiffnesses were evaluated by ultrasonic spectroscopy methods for the bulk (longitudinal and transverse) wave reflection coefficients and the anti-symmetric mode interface ...
Rahman M S - - 2007
A pressure to voltage transducer is used along with a cuff, in a PC-based blood pressure and pulse rate monitoring system for human body. During the blood pressure measurement cycle, the output voltage of the pressure to voltage transducer is recorded digitally using a data acquisition system. The recorded data ...
Chen Hsing I - - 2008
Aortic stiffness (AS) exerts significant impact on the cardiovascular risks. We developed a new model to produce AS. The purposes were to evaluate the haemodynamic consequence and to correlate the haemodynamic parameters with the extent of ventricular hypertrophy (VH). We applied silicon gel for embedding of the abdominal and/or thoracic ...
Payne R A - - 2007
BACKGROUND: Wideband external pulse (WEP) monitoring, using a broad bandwidth piezoelectric sensor located over the brachial artery under the distal edge of a sphygmomanometer cuff, can be used for evaluating the contour of the arterial pressure pulse wave. The pulse contour contains valuable information relating to cardiovascular function which may ...
Essalihi Rachida - - 2007
OBJECTIVE: Medial elastocalcinosis (MEC) contributes to the development of large artery stiffness and isolated systolic hypertension. Since endothelin receptor antagonists can prevent and regress elastocalcinosis, our aim was to determine whether amlodipine, a calcium channel blocker that inhibits endothelin signaling, could likewise influence MEC, or reduce pressure mainly through its ...
Dobson Gary - - 2007
The radial artery (RA) pressure waveform is commonly used to reconstruct the central aortic pressure waveform. Because the RA pressure waveform has been used as input to this process, its features that are dependent on the local arterial properties can influence the final reconstructed aortic waveform. In this study, we ...
Ellis Tim - - 2007
We present a new analysis and visualization method for studying the functional relationship between the pulse morphology of pressure signals and time or signal metrics such as heart rate, pulse pressure, and means of pressure signals, such as arterial blood pressure and central venous pressure. The pulse morphology is known ...
Chen Ju-Yi - - 2007
OBJECTIVE: Although large-artery stiffness is a well-known independent factor for cardiovascular risk, the importance of small-artery stiffness is not well elucidated. We have developed a novel Compliance Index as a marker of small-artery stiffness. This study aimed to determine the clinical significance of this index by evaluating 140 patients without ...
Hope Sarah A - - 2007
OBJECTIVE: Arterial transfer functions (TFs) describe the relationship between the pressure waveform at different arterial sites. Generalized TFs are used to reconstruct central aortic waveforms from non-invasively obtained peripheral waveforms and have been promoted as potentially clinically useful. A limitation is the paucity of information on their 'generalizability' with no ...
Park Hun-Jun - - 2007
BACKGROUND: The brachial-ankle pulse wave velocity (baPWV) is a useful parameter to assess arterial stiffness. However, it is difficult to evaluate arterial stiffness in hypertensive patients because the baPWV is affected by the blood pressure itself. This study was designed to estimate the relationship between the change of the blood ...
Bodlaj Gerd - - 2007
PURPOSE: Pulse wave velocity (PWV) is at least partially controlled by vascular tone. Vascular tone and underlying physiological processes such as sympathetic activity, plasma catecholamin, and cortisol levels have been shown to follow diurnal variations. MATERIALS AND METHODS: Carotid-to-radial PWV was non-invasively assessed by applanation tonometry in 21 young (26.5+/-2.3 ...
Ohno Y - - 2008
Pulse wave analysis was performed in apparently normal volunteers (n=164) and in essentially hypertensive patients without cardiovascular complications (n=171) using a newly developed non-invasive pulse wave measurement device (HEM-9010AI). Our results suggest that early wave reflections measured by radial augmentation index (AIr) are enhanced in volunteers with systolic blood pressure ...
Sommerfield Andrew J AJ Department of Diabetes, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh, Scotland, - - 2007
To examine the effects of intravenous insulin and acute hypoglycemia on arterial wall stiffness and central hemodynamic responses in adults with and without type 1 diabetes. In 30 young male volunteers [10 nondiabetic (Group 1); 10 with type 1 diabetes, <5 yr duration (Group 2); 10 with type 1 diabetes, ...
Blyth Kevin G - - 2007
In the Framingham studies, systemic arterial pulse pressure correlated linearly with morbidity and mortality. Right ventricular (RV) systolic dysfunction and pulmonary circulation stiffening result in abnormalities of pulmonary arterial (PA) pulse pressure in PA hypertension (PAH). We investigated the prognostic potential of PA pulse pressure in 67 patients with PAH ...
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