Search results for "Hemodynamic"
showing 10 items of 526 documents
Detection of coronary artery calcifications predicting coronary heart disease: comparison of fluoroscopy and spiral CT.
1998
The aim of this study was to evaluate the clinical relevance of coronary artery calcifications detected by spiral CT, congruence with fluoroscopy (FS) and coronary angiography, and comparison with studies reporting on application of double-helical CT and ultrafast CT. Forty patients underwent spiral CT (2-mm slice thickness, table feed 3 mm/s), coronary angiography, and FS (performed in the usual manner). Stenosis and calcifications were evaluated semiquantitatively. Nineteen patients suffering from a stenosis ≥ 75 % were verified at coronary angiography. All had coronary artery calcification on spiral CT. Fluoroscopy did not detect 8 of 19 patients with a stenosis ≥ 75 % (1 vessel: n = 1; …
Biomechanical Determinants of Right Ventricular Failure in Pulmonary Hypertension.
2018
Pulmonary hypertension (PH) is a disease characterized by progressive adverse remodeling of the distal pulmonary arteries, resulting in elevated pulmonary vascular resistance and load pressure on the right ventricle (RV), ultimately leading to RV failure. Invasive hemodynamic testing is the gold standard for diagnosing PH and guiding patient therapy. We hypothesized that lumped-parameter and biventricular finite-element (FE) modeling may lead to noninvasive predictions of both PH-related hemodynamic and biomechanical parameters that induce PH. We created patient-specific biventricular FE models that characterize the biomechanical response of the heart and coupled them with a lumped-paramete…
Renal plasma flow, filtration fraction and microalbuminuria in hypertensive patients: Effects of chronic smoking
2005
SUMMARY: Introduction: Albumin excretion rate is usually increased in people who smoke, but the physiological basis of this phenomenon is not fully understood. Methods: The effect of chronic smoking on renal haemodynamics was studied in a cohort of 66 men. Twenty-seven were smokers and 36 were hypertensive. In all subjects, the albumin excretion rate was evaluated; in hypertensive patients, a renoscintigraphic evaluation of renal plasma flow and glomerular filtration were carried out and the filtration fraction was calculated. Results: The hypertensive smoking population presented an increased urinary albumin excretion rate in comparison with hypertensive non-smoking patients. No signifi…
Sympathetic Activity and Blood Pressure Pattern in Autosomal Dominant Polycystic Kidney Disease Hypertensives
1998
To study the potential role of sympathetic activity in the pathogenesis of arterial hypertension associated with autosomal dominant polycystic kidney disease (ADPKD) and to analyze its relationship with 24-hour blood pressure pattern, plasma catecholamines and 24-hour ambulatory blood pressure monitoring were evaluated in 30 ADPKD hypertensive patients (of which 17 without and 13 with renal failure) and in 50 essential hypertensives. The groups were matched for sex, body mass index, known duration of hypertension, and clinic blood pressure. Plasma catecholamines, determined in resting position, were higher in ADPKD patients without renal failure than in essential hypertensives. Nighttime di…
Effects of exhaustive stretch-shortening cycle exercise on muscle blood flow during exercise
2006
Aim: The influence of exhaustive stretch-shortening cycle exercise (SSC) on skeletal muscle blood flow (BF) during exercise is currently unknown. Methods: Quadriceps femoris (QF) BF was measured in eight healthy men using positron emission tomography before and 3 days after exhaustive SSC exercise. The SSC protocol consisted of maximal and submaximal drop jumps with one leg. Needle biopsies of the vastus lateralis muscles were taken immediately and 2 days after SSC for muscle endothelial nitric oxide synthase (eNOS) and interleukin-1-beta (IL-1β) mRNA level determinations. Results: All subjects reported subjective muscle soreness after SSC (P < 0.001), which was well in line with a decre…
Pulse pressure amplification and its determinants
2015
Background. Pulse pressure (PP) amplification expressed as the peripheral-to-central PP ratio has gained importance in the assessment of cardiovascular phenotypes and cardiovascular risk. The aim of the present study was to assess the relationship between PP amplification, large vessel parameters and peripheral blood pressure (BP) to gain insights into the amplification phenomenon. Methods. Peripheral BP, central BP and carotid-femoral pulse wave velocity (cfPWV) were assessed using the OMRON M6, SphygmoCor and Complior devices, respectively, in 741 adults attending the hypertension outpatient clinic. Analysis of covariance, partial correlations and multiple linear regression models were pe…
Autonomic dysfunction in patients with achalasia.
1995
It has been previously shown that patients with achalasia may have motor abnormalities of the stomach, small bowel and biliary system. This study investigates whether a disturbance of extraintestinal autonomic function occurs. Autonomic function studies were performed in 15 patients with achalasia and 15 age- and sex-matched healthy controls. Pupillo-grams were obtained during darkness, light exposure and after pilocarpine administration. Cardiovascular function studies included determinations of heart rate variation during deep breathing and orthostasis. In addition, we determined blood pressure changes in response to sustained handgrip, cold exposure and orthostasis. Neurohormonal functio…
Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion
2013
The physiological responses to water immersion (WI) are known; however, the responses to stress following WI are poorly characterized. Ten healthy men were exposed to three physiological stressors before and after a 6-h resting WI (32–33°C): 1) a 2-min cold pressor test, 2) a static handgrip test to fatigue at 40% of maximum strength followed by postexercise muscle ischemia in the exercising forearm, and 3) a 15-min 70° head-up-tilt (HUT) test. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), cardiac output (Q̇), limb blood flow (BF), stroke volume (SV), systemic and calf or forearm vascular resistance (SVR and CVR or FVR), baroreflex sensitivity (BRS), and HR variabili…
Skeletal muscle blood flow and flow heterogeneity during dynamic and isometric exercise in humans
2002
The effects of dynamic and intermittent isometric knee extension exercises on skeletal muscle blood flow and flow heterogeneity were studied in seven healthy endurance-trained men. Regional muscle blood flow was measured using positron emission tomography (PET) and an [15O]H2O tracer, and electromyographic (EMG) activity was recorded in the quadriceps femoris (QF) muscle during submaximal intermittent isometric and dynamic exercises. QF blood flow was 61% ( P = 0.002) higher during dynamic exercise. Interestingly, flow heterogeneity was 13% ( P = 0.024) lower during dynamic compared with intermittent isometric exercise. EMG activity was significantly higher ( P < 0.001) during dynamic e…
The association between muscle EMG and perfusion in knee extensor muscles
2006
The relationships between electromyographic (EMG) activity and force as well as muscle blood flow and work have been well established. However, the association between muscle blood flow and EMG activity remains unsolved. Thus, to test the hypothesis that muscle EMG activity relates to muscle perfusion in different compartments of the quadriceps femoris (QF) muscle, 12 healthy male subjects were studied. During two very submaximal exercise bouts, at different exercise intensities, oxygen labelled radiowater and positron emission tomography were used to measure muscle perfusion. In addition, produced force of knee extensors and muscle EMG activity in the vastus lateralis (VL), vastus medialis…