Search results for "VELOCITY"
showing 10 items of 881 documents
Arterial stiffness in obese CPAP-treated obstructive sleep apnea (OSA): A seven years prospective longitudinal study
2017
Introduction: Arterial stiffness measured by carotid-femoral pulse wave velocity (PWV) is elevated in severe OSA. A 1m/s increase in PWV is associated with a 15% increased risk of mortality. There is a paucity of data regarding long term evolution of PWV in CPAP-treated OSA. Aims: To measure PWV evolution in CPAP-treated OSA. Methods: In a prospective obese OSA cohort, we collected PWV, clinical and biological metabolic data, incident cardiovascular events and CPAP adherence at time of diagnosis and after at least 5-year follow-up. Results: 72 OSA (men: 52.8%, median age: 55.8 years and median BMI of 38.5 kg/m2) with a high prevalence of hypertension: 58.3%, Type 2 diabetes: 20.8%, hypercho…
Dofetilide effects on the inhibition by trains of subthreshold conditioning stimuli.
2004
We investigated the electrophysiological actions of dofetilide upon the ventricular myocardium to determine whether the drug modifies the inhibitory effects of subthreshold stimuli trains upon ventricular refractoriness. In nine Langendorff perfused rabbit hearts, ventricular epicardial electrodes were used to determine the following parameters at baseline and during dofetilide perfusion (0.5 micromolar): effective (ERP) and functional (FRP) refractory periods, conduction velocity (CV), wavelength (WL), and ERP prolongation (inhibitory effect) induced by subthreshold stimuli trains (STr) at pulse frequencies of 100, 300, and 600 Hz. Dofetilide significantly prolongs ventricular refractorine…
Color Doppler imaging of the eye and orbit A synopsis of a 400 case experience
2009
Color Doppler imaging (CDI) is a recent advance in ultrasonography that allows simultaneous two-dimensional imaging of structure and blood flow. Doppler information is superimposed in color over a conventional gray-scale ultrasound image. Using this technique we have examined 400 eyes. The central retinal artery, posterior ciliary arteries, ophthalmic artery, the central retinal vein and the vortex veins could be located in all normal eyes. Using the color image as a guide, Doppler spectral analysis is used for quantitative assessment of blood flow velocity in these vessels. We also studied patients with intraocular tumors, arterial and venous retinal occlusions, orbital vascular anomalies …
Blood flow velocity waveforms of the middle cerebral artery and abnormal neurological evaluations in live-born fetuses with absent or reverse end-dia…
1992
Abstract We studied 37 fetuses with absent or reverse end-diastolic flow velocities (AREDFV) of the umbilical arteries with respect to the mode of delivery, fetal acidosis, resistance index of the middle cerebral arteries, and abnormal neurological evaluation at the time of discharge from the department of pediatrics. A control group with normal umbilical artery flow velocity waveforms was matched for gestational age. Fetuses with AREDFV were delivered almost exclusively by cesarean section, in most cases due to fetal distress. Metabolic changes with decreased base excess values were found more often in fetuses with AREDFV, but no difference could be detected with respect to severe fetal ac…
Subclinical cardiovascular damage in patients with HCV cirrhosis before and after treatment with direct antiviral agents: a prospective study
2018
BACKGROUND Cirrhosis is associated with morpho-functional cardiovascular alterations. AIMS To detect early features of cardiovascular damage in HCV-compensated cirrhotic patients using myocardial deformation indices and carotid arterial stiffness, and, further, to evaluate their short-term behaviour after HCV eradication with direct antiviral agents (DAAs). METHODS Thirty-nine consecutive patients with HCV cirrhosis, without previous cardiovascular events, were studied and matched for age, gender and cardiovascular risk factors to 39 controls without liver or cardiovascular disease. Patients and controls underwent a baseline echocardiographic evaluation including global longitudinal strain …
Variations in acoustical beam properties of intracoronary Doppler catheters.
1993
The limitations of coronary angiography in assessing the functional significance of coronary obstructions is well known. While the critical variable of coronary blood flow cannot be readily measured, intraluminal Doppler sonography offers useful related functional information on blood flow velocity. In order to fully evaluate Doppler signals it is essential to have exact knowledge of the transducer transmission characteristics and of the ultrasound beam topology. In an experimental set-up, the transmitter-receiver characteristics of five commonly used Doppler catheters were investigated. In comparing the beam characteristics we found inhomogeneities in the lateral beam spread. At a penetrat…
Association between increased arterial stiffness and clinical outcomes in patients with early sepsis: a prospective observational cohort study.
2019
Background Conduit arteries, especially the aorta, play a major role in ensuring efficient cardiac function and optimal microvascular flow due to their viscoelastic properties. Studies in animals and on isolated arteries show that acute systemic inflammation can cause aortic stiffening which affects hemodynamic efficiency. Carotid-femoral pulse wave velocity, a measure of aortic stiffness, may be useful as a bedside investigational method in patients with early sepsis admitted to intensive care, as circulatory changes can lead to multiple organ failure and increased mortality. This study aims to investigate arterial stiffness in early sepsis and its association with clinical outcomes. Metho…
Conduction velocity study in type 1 diabetic patients.
1989
The role of metabolic abnormalities in the development of diabetic neuropathy is controversial. To investigate the peripheral nerve function and the influence of hyperglycemia on nerve conduction in insulin-dependent diabetes, a one-year neurophysiological study was carried out in 30 type 1 diabetic patients ranging in age from 2-16 years. During the 12-month follow-up period the glycosylated hemoglobin determination, motor conduction velocity of the peroneal nerve and the motor and sensory conduction of the tibial nerve were assessed 3 times, at the beginning of the study and every 6 months thereafter. The sensory latency was found significantly delayed in these patients as compared with t…
Effect of acetyl-l-carnitine in the treatment of diabetic peripheral neuropathy : A systematic review and meta-analysis
2017
Background/aim: Deficiency of acetyl-L-carnitine (ALC) and L-carnitine (LC) appears to play a role in peripheral diabetic neuropathy, although the evidence in humans is still limited. We conducted a systematic review and meta-analysis investigating the effect of ALC on pain and electromyographic parameters in people with diabetic neuropathy. Methods: A literature search in major databases, without language restriction, was undertaken. Eligible studies were randomized controlled trials (RCTs) or pre-and post-test studies. The effect of ALC supplementation on pain perception and electromyographic parameters in patients with diabetic neuropathy was compared vs. a control group (RCTs). The effe…
[Effect of flecainide on longitudinal and transverse conduction velocities in ventricular myocardium. An experimental study].
2007
It is known that the effect of flecainide on longitudinal and transverse ventricular conduction velocities depends on the coupling interval. If this is so, whether the longitudinal or transverse direction is predominantly affected could depend on the magnitude of the coupling interval. In order to investigate this hypothesis, we studied the effect of flecainide, 1 micromol/L, on conduction velocities in excised heart preparations from 11 rabbits using a basal cycle length of 250 ms and inserting two extrastimuli at a decreasing coupling interval. Flecainide significantly reduced both conduction velocities. However, the effect increased as the coupling interval decreased for only the longitu…