منابع مشابه
Pressure Gradients without Obstruction
OBSTRUCTION to left ventricular outflow has been considered a characteristic and functionally important feature of "hypertrophic subaortic stenosis." The presence of obstruction has been inferred from the finding of a pressure gradient within the left ventricle during catheterization of the left heart in certain patients with idiopathic left ventricular hypertrophy. Indeed, the disease was not ...
متن کاملFluid dynamics of aortic stenosis: subvalvular gradients without subvalvular obstruction.
Analysis of a tapering, pulsatile flow field predicts that substantial subvalvular pressure gradients exist in patients with valvular aortic stenosis (AS) without invoking a second anatomic site of obstruction. Using a catheter with two laterally mounted micromanometers, we examined the left ventricle in 11 patients with AS, mean age 64 +/- 11 years (+/- SD); the mean valve area was 1.0 +/- 0.3...
متن کاملfor “ Infotaxis : searching without gradients ”
Here, v is the velocity of the searcher and dc/dr is the concentration gradient. The first inequality in (3) gives the condition that the signal-to-noise ratio for the difference in the number of hits experienced by the searcher across the integration time Tint be larger than unity. The second inequality is the requirement of locality, i.e. that the change in concentration across the distance s...
متن کاملDirect numerical simulation of turbulent boundary layers with and without pressure gradients
Direct Numerical Simulations (DNS) of developing turbulent boundary layers have been performed using a Finite Volume method with a locally refined grid near the wall. In the case of a zero pressure gradient boundary layer it is shown that the use of local grid refinement saves a considerable amount of computational resources. The method is then applied to an adverse pressure gradient boundary l...
متن کاملNoninvasive assessment of ejection intraventricular pressure gradients.
OBJECTIVES The study was designed to validate in vivo a new method to measure ejection intraventricular pressure gradients (IVPGs) by processing color M-mode Doppler data and to assess the effects of inotropic interventions on IVPGs in the clinical setting. BACKGROUND In the absence of obstruction, ejection IVPGs cannot be estimated by Doppler using the simplified Bernoulli equation. METHOD...
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ژورنال
عنوان ژورنال: Circulation
سال: 1965
ISSN: 0009-7322,1524-4539
DOI: 10.1161/01.cir.32.6.881