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Results 451 - 500 of 1762
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Zachary James F JF Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA. - - 2006
Arterial injury resulting from the interaction of contrast agent (CA) with ultrasound (US) was studied in rabbit auricular arteries and assessed by histopathologic evaluation and s-thrombomodulin concentrations. Three sites on each artery were exposed (2.8 MHz, 5-min exposure duration, 10-Hz pulse repetition frequency, 1.4-mus pulse duration) using one of three ...
Eide P K - - 2006
BACKGROUND: It was previously reported that the intracranial pulse pressure amplitudes were elevated in idiopathic normal pressure hydrocephalus (iNPH) patients responding to shunt surgery. In this study, pulse pressure amplitudes were determined in all patients referred for tentative iNPH, and patients were selected for shunt surgery based on the determination ...
Drighil Abbdenasser - - 2008
Hemodialysis (HD) has been associated with an increase in the amplitude of QRS complexes. Experience in a single patient with multiple measurements has shown that HD leads also to augmentation of P-wave amplitude. The objective of this investigation was to evaluate electrocardiogram (ECG) changes with HD in a cohort of ...
Abhayaratna Walter P - - 2006
There is a paucity of data regarding the relation between the various noninvasive indexes of arterial stiffness and left ventricular diastolic function. In 188 subjects aged > or =65 years (mean 75 +/- 5; 71% men), the concordance and strength of the association between measures of arterial stiffness and left ...
Llamas Bastien - - 2006
By continuous monitoring of abdominal aortic blood pressure via telemetry in conscious rats, we have observed that systolic, diastolic, and pulse pressures of male Brown-Norway rats were all significantly lower than that of male Wistar-Kyoto rats, despite the fact that all of the values in both strains were within normotensive ...
Huang Yongli - - 2006
We report experimental results from a comparative study on collapsed region and conventional region operation of capacitive micromachined ultrasonic transducers (CMUTs) fabricated with a wafer bonding technique. Using ultrasonic pulse-echo and pitch-catch measurements, we characterized single elements of 1-D CMUT arrays operating in oil. The experimental results from this study ...
Baulmann Johannes - - 2006
OBJECTIVE: We have recently shown that mean pulse pressure is higher in patients with transient myocardial ischemia. Pulse pressure elevation might be an important consequence of increased arterial stiffness. The aim of this study was to prove if arterial stiffness is changed in patients with transient myocardial ischemia who bear ...
Binder Josepha - - 2006
BACKGROUND: We investigated whether the aortic augmentation index (AIx), a measure of arterial wave reflection and stiffness, is associated with cardiorespiratory fitness in men without known coronary heart disease (CHD). METHODS: Asymptomatic men (n = 201, mean age 51 +/- 9.2 years) referred for a screening exercise electrocardiogram (ECG) underwent ...
Hirata Kozo - - 2006
The pulsatile component of blood pressure (ie, pulse pressure) has received considerable attention as an important risk factor for cardiovascular disease. In particular, central blood pressure measurements in the ascending aorta or in the carotid artery are expected to be more useful than conventional brachial pressure measurements for predicting cardiovascular ...
Amoore John N - - 2006
OBJECTIVE: Oscillometric noninvasive blood pressure measurement devices determine the pressures by analysing the relationship between the pressure in an occluding cuff and low-amplitude pressure pulses (oscillometric pulses) induced in the cuff by the arterial pressure wave. This paper examines the effects on the pulses and oscillometric pulse amplitude envelope of ...
Stokes Gordon S - - 2006
Isolated systolic hypertension (ISH) is the dominant form of hypertension in the elderly. It is associated with increased arterial pulse pressure, to which an early-returning and magnified pulse-wave reflection makes an important contribution. Treatment of ISH with diuretics, calcium channel blockers (CCBs), and angiotensin II inhibitors is effective in reducing ...
McManus John G - - 2006
OBJECTIVES: Previous animal and human experiments have suggested that reduction in central blood volume either increases or decreases the amplitude of R waves in various electrocardiograph (ECG) leads depending on underlying pathophysiology. In this investigation, we used graded central hypovolemia in adult volunteer subjects to test the hypothesis that moderate ...
Karamanoglu Mustafa - - 2006
Tracking changes in stroke volume or cardiac output (CO) can be useful in the diagnosis and treatment of various cardiac illnesses. Existing arterial pressure waveform based pulse contour CO algorithms perform poorly during altered systemic hemodynamics. In this study, a right ventricular pressure waveform based pulse contour CO algorithm was ...
Safar Michel E - - 2006
This review offers a critical evaluation of the remarkable progress in antihypertensive therapy since its inception. Despite the introduction of newer, more sophisticated drugs, treatment results have remained stable. Problems impeding further improvement include limited patient compliance, clinical inertia, incomplete adherence to guidelines, and dependence on brachial artery cuff pressures ...
Safar Michel E - - 2006
Pulsatile arterial hemodynamics in cardiovascular diseases indicate that the aortic blood pressure curve may be represented by 2 different phenotypes: one in patients 64 years old and younger and the other in subjects older than 65 years. The 2 blood pressure curves may have exactly the same mean arterial pressure ...
Tochikubo Osamu - - 2006
BACKGROUND: There are almost no reports on the physiological effects of the various electric massage devices available on the market. This report describes the effects on peripheral vascular circulation and autonomic-nervous system activity of a pulse-synchronized air-massage (PS-AM) device in which cuffs apply air pressure cyclically to the lower limbs ...
Westerhof Berend E - - 2006
Wave reflections affect the proximal aortic pressure and flow waves and play a role in systolic hypertension. A measure of wave reflection, receiving much attention, is the augmentation index (AI), the ratio of the secondary rise in pressure and pulse pressure. AI can be limiting, because it depends not only ...
McEniery Carmel M - - 2006
Arterial stiffness is an independent predictor of mortality and is regulated by a number of factors, including vascular smooth muscle tone. However, the relationship between endothelial function and definitive measures of arterial stiffness and wave reflections has not been described in healthy individuals. Therefore, we tested the hypothesis that endothelial ...
Nichols Wilmer W - - 2006
OBJECTIVES: To determine if arterial properties and wave reflection characteristics are favorably altered after enhanced external counterpulsation (EECP) treatment in patients with refractory angina. BACKGROUND: Early return of reflected waves from the lower body, resulting from increased arterial stiffness, augments central aortic pressure and increases left ventricular (LV) afterload and ...
Talts Jaak - - 2006
The volumetric pulses in the finger PPG signal appear as an information source for several indirect measurement methods. In this study we modelled transformation of pressure pulses into volume pulses in a wide transmural pressure range. The noninvasive finger arterial pressure and photoplethysmographic (PPG) signals were simultaneously registered in 13 ...
Bellido Claudio A - - 2006
Pulse wave velocity is a reliable marker of arterial compliance. Stiffness of large and elastic arteries leads to a faster propagation of pulse wave. The aim of this study was to evaluate changes in arterial distensibility using antihypertensive drugs. This treatment focused on the inhibition of the renin-angiotensin-aldosterone system and ...
Bitigen Atila - - 2006
OBJECTIVE: The aim of this study was to evaluate whether there is a relationship between aortic elastic properties and diurnal blood pressure rhythm in hypertensive subjects. METHODS AND RESULTS: This study included 41 hypertensive patients who were taking medical treatment and had undergone ambulatory blood pressure monitoring (ABPM). The patients ...
Ergul Adviye - - 2006
Endothelin-1 stimulates collagen synthesis and is increased in hypertension, but its effect on collagen degradation remains unknown. The current study tested the hypothesis that elevated endothelin-1 levels are associated with decreased collagenase activity, markers of collagen degradation, and arterial compliance in hypertensive patients. Normotensive (n = 10) and hypertensive (n ...
Millasseau Sandrine C - - 2006
Analysis of the contour of the peripheral pulse to assess arterial properties was first described in the nineteenth century. With the recognition of the importance of arterial stiffness there has been a resurgence of interest in pulse wave analysis, particularly the analysis of the radial pressure pulse acquired using a ...
O'Rourke Michael F MF St. Vincent's Clinic/VCCRI, University of New South Wales, Sydney, Australia. - - 2006
The ubiquitous brachial cuff method gained widespread clinical acceptance for blood pressure recording after confirmation of its prognostic value in 1917. This method displaced radial pulse waveform analysis by sphygmography, which also gave prognostic Information but was difficult to use. Since that time, brachial cuff sphygmomanometry has migrated from the ...
Norman Brian C - - 2006
The well recognized cardiac effects of severe hyperkalemia include progressive rhythm and conduction disturbances such as bradycardia, spiked and narrow T waves, widening QRS complex, widening and flattening P wave, disappearance of the P wave, and cardiac arrest. Paradoxically, a heart rate greater than 200 beats/min may coexist with hyperkalemia ...
Mori Akira - - 2007
BACKGROUND: Changes in the vessel lumen diameter pulse waveform closely follow changes in the transmural pressure pulse waveform. AIM: To study diameter pulse waveform recorded noninvasively from the fetal inferior vena cava (IVC) in fetuses with cardiac abnormality. STUDY DESIGN: A paired ultrasonic phase-locked echo tracking system with a high ...
Waring W Stephen - - 2006
AIMS: Endothelial function is characteristically impaired in patients with hypertension. Endothelial function was assessed in men and women with hypertension using a recently described, non-invasive method. METHODS: Twenty patients and 20 controls received salbutamol 400 microg and glyceryl trinitrate (GTN) 500 microg in a two-way randomized, single-blind study. Effects on ...
Shigemura Katsumi - - 2006
BACKGROUND: The problems of patients with erectile dysfunction have been recognized, leading to the emergence of sildenafil, which has led to successful treatment in many cases. The purpose of this study is to examine the effect of sildenafil on the pulse wave velocity of patients with erectile dysfunction. METHODS: Fifteen ...
Munakata Masanori - - 2006
Brachial-ankle pulse wave velocity is a new measure of arterial stiffness. The clinical significance of brachial-ankle pulse wave velocity as a measure of early vascular damage remains unclear. We examined the hypothesis that higher brachial-ankle pulse wave velocity is associated with a much greater risk of albuminuria by employing a ...
Towe Bruce C - - 2006
Periodic pulses of intense ultrasound energy at 70 kHz with 5-ms duration at 3 MPa SPL applied to the exposed pig myocardium at physiologic rhythms were observed to produce cardiac pacing. Ten animals were successfully paced at pulse width and energy conditions above a certain threshold. Sigmoid strength-duration curves characterizing ...
Lockhart Christopher J - - 2006
Quantitative analysis of the arterial pressure pulse waveform recorded by applanation tonometry of the radial artery can track NO (nitric oxide)-mediated modulation of arterial smooth muscle tone. The changes in pressure pulse waveform morphology result from pulse wave reflection arising predominantly from smaller arteries and arterioles. Employing Doppler ultrasound to ...
Vanmolkot Floris H M - - 2006
BACKGROUND AND OBJECTIVES: Sumatriptan, a 5-hydroxytryptamine (HT)(1B/1D) receptor agonist, is an effective acute antimigraine drug. Because of its vasoconstrictor activity, it is contraindicated in patients at high risk for adverse cardiovascular events. Acute antimigraine drugs without vasoconstrictor effects are currently being developed, and sensitive, noninvasive techniques by which to detect ...
Kabal John - - 2006
To correlate the values in the basic blood pressure groups presented in the JNC 7th with the computed values of the Noninvasive Hemodynamic Analyzer (NHA) and to demonstrate the pathophysiological alterations by three proportional hypertensive models. Hemodynamic values of each of the blood pressure groups presented in the JNC 7th ...
Franklin Stanley S - - 2006
Once considered part of the normal aging process, the development of isolated systolic hypertension represents a late manifestation of increased arterial stiffness in older people. Furthermore, isolated systolic hypertension is the single most frequent subtype of hypertension in the US adult population. Indeed, central arterial stiffness rather than peripheral vascular ...
Mallareddy Madhavi - - 2006
Arterial stiffness is an independent cardiovascular prognostic factor and is modulated by angiotensin-converting enzyme inhibitors (ACEIs). The authors performed a meta-analysis of clinical trials investigating the effects of ACEIs on pulse wave velocity (PWV) or augmentation index. The search included randomized clinical trials as well as uncontrolled studies that measured ...
Gruss Eyal - - 2006
BACKGROUND: We review the accepted primary blast injury criteria. We point out a significant systematic error in the criteria due to the use of low-quality pulse duration data in the original criteria. METHODS: We recalculate the injury criteria using state-of-the-art blast data. RESULTS: We give the corrected injury criteria in ...
Stok Wim J - - 2006
Noninvasive finger blood pressure has become a surrogate for central blood pressure under widely varying circumstances. We tested the validity of finger-aorta transfer functions (TF) to reconstruct aortic pressure in seven cardiac patients before, during, and after incremental bicycle exercise. The autoregressive exogenous model method was used for calculating finger-aorta ...
Nestel Paul P Baker Heart Research Institute Wynm Domain, Melbourne, Australia. paul.nestel@baker.edu.au - - 2007
Isoflavones reduce arterial stiffness, a predictor of cardiovascular events. Whether metabolites of isoflavones have similar bioactivity is unknown. The effect of supplemental trans-tetrahydrodaidzein (THD) a metabolite of daidzein on pulse wave velocity (PWV), a measure of arterial stiffness was tested in overweight men and postmenopausal women. 25 subjects, 11 postmenopausal ...
Syme Douglas A - - 2006
A large central compliance is thought to dominate the hemodynamics of all vertebrates except birds and mammals. Yet large crocodilians may adumbrate the avian and mammalian condition and set the stage for significant wave transmission (reflection) effects, with potentially detrimental impacts on cardiac performance. To investigate whether crocodilians exhibit wave ...
Zhang Xin-Yu - - 2006
Pulse transit time (PTT) is a simple, noninvasive technique which shows great promise in the continuous monitoring of blood pressure and the assessment of arterial stiffness, and has potential applications in wearable healthcare devices. Usually, PTT is measured from the electrocardiogram (ECG) R-wave to a characteristic point on the peripheral ...
Safar Hélène - - 2006
Isolated systolic hypertension is an important cardiovascular risk factor in the elderly. In addition to systolic blood pressure, pulse pressure, pulse wave velocity, and carotid wave reflections are also strong cardiovascular risk factors in the elderly, as a consequence of the two main determinants of systolic hypertension: increased arterial stiffness ...
Andoh Norikazu - - 2006
The objective of the present study was to examine the relationship between markers of inflammation, such as high-sensitivity C-reactive protein (hsCRP) and erythrocyte sedimentation rate (ESR), and brachial-ankle pulse wave velocity (baPWV), an indicator of arterial stiffness, in Japanese men. We studied 269 male subjects (mean age, 53 years) who ...
Ohya Yusuke - - 2006
BACKGROUND: Chronic kidney disease (CKD) is a risk factor for future cardiovascular disease. Although pulse wave velocity (PWV), which reflects arterial stiffness, was increased in subjects with CKD, little is known regarding whether renal function is associated with PWV in a low-risk population and whether proteinuria and decreased renal function ...
Dark Paul - - 2006
OBJECTIVE: To determine the effects of hemorrhage on wave-reflection-induced systolic pressure augmentation in the aorta. DESIGN: Randomized, controlled laboratory experiment. SETTING: University research laboratory. SUBJECTS: Twenty-five anesthetized pigs randomized to surgical controls (n = 7), hemorrhage (n = 9, H), and hemorrhage with reinfusion (n = 9, HR). INTERVENTIONS: Hemorrhage ...
McNulty M - - 2006
Although arterial stiffness is an independent cardiovascular risk factor associated with both aging and hypertension, relatively little is known regarding the structural changes in the vessel wall that occur with vessel stiffening. We determined if collagen type-I metabolism is related to arterial stiffening in both hypertensive and normotensive subjects. Arterial ...
Shelley Kirk H - - 2006
OBJECTIVE: In the process of determining oxygen saturation, the pulse oximeter functions as a photoelectric plethysmograph. By analyzing how the frequency spectrum of the pulse oximeter waveform changes over time, new clinically relevant features can be extracted. METHODS: Thirty patients undergoing general anesthesia for abdominal surgery had their pulse oximeter, ...
Stokes Gordon S - - 2006
Isolated systolic hypertension (ISH) is an important cause of strokes and heart failure among the elderly, but it is difficult to control in some elderly patients, even with combination antihypertensive therapy. The presence of a prominent reflection wave in the arterial pulse-wave profile of such patients signifies that adjuvant nitrate ...
Shirai Kohji - - 2006
To measure the stiffness of the aorta, femoral artery and tibial artery noninvasively, cardio-ankle vascular index (CAVI) which is independent of blood pressure was developed. The formula for measuring this index is; CAVI=a{(2rho/DeltaP) x ln(Ps/Pd)PWV(2)} + b where, Ps and Pd are systolic and diastolic blood pressures respectively, PWV is ...
Dobson G - - 2006
OBJECTIVES: Endografting is being used to manage aneurysms, dissections and acute traumatic disruptions of the thoracic aorta. The acute effects of such interventions on ventricular afterload and on pressure wave transmission characteristics are not well known. METHODS: In five dogs, a 55 mm endograft was introduced into the descending aorta, ...
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