منابع مشابه
Atrioventricular Pressure Half-Time
was less than 25 msec. Although exercise increased the atrioventricular pressure gradient, heart rate, and cardiac output significantly, the half-time was affected only slightly. Mitral regurgitation of various severities did not affect the half-time. The half-time appears to vary inversely with the anatomic orifice area of the mitral valve. The determination of the half-time obviates the need ...
متن کاملNoninvasive assessment of atrioventricular pressure half-time by Doppler ultrasound.
The mean pressure drop across the mitral valve and atrioventricular pressure half-time were measured noninvasively by Doppler ultrasound in 40 normal subjects, in 17 patients with mitral regurgitation, 32 patients with mitral stenosis and 12 with combined stenosis and regurgitation. In normal subjects pressure half-times were 20--60 msec, in patients with isolated mitral regurgitation 35--80 ms...
متن کاملComparison of mitral valve area by pressure half-time and proximal isovelocity surface area method in patients with mitral stenosis: effect of net atrioventricular compliance.
AIMS The aim of this study was to test the hypothesis that, unlike calculation of the mitral valve area (MVA) with the pressure half-time method (PHT), the proximal isovelocity surface area method (PISA) is not affected by changes in net atrioventricular compliance (C(n)). METHODS AND RESULTS We studied 51 patients with mitral stenosis (MS) from two centres. MVA was assessed with the PISA (MV...
متن کاملHigh-pressure structure of half-metallic CrO2
Evidence for a structural phase transition from rutile -CrO2 phase I P42/mnm to orthorhombic -CrO2 phase II CaCl2-like, Pnnm is presented using angle-resolved synchrotron x-ray diffraction and highsensitivity confocal Raman spectroscopy. The transition to the CaCl2 structure, which appears to be second order, occurs at 12±3 GPa without any measurable discontinuity in volume, but is accompanied ...
متن کاملEffect of changes in heart rate on pressure half time in normally functioning mitral valve prostheses.
To test the validity of a relation between the pressure half time and the diastolic time interval, previously shown in a pulse duplication system, eight patients with prosthetic mitral valves and permanent pacemaker systems were studied. Recordings were made from the apex by continuous wave or pulsed Doppler echocardiography at heart rates between 75 and 150 beats/min. The pressure half time wa...
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ژورنال
عنوان ژورنال: Circulation
سال: 1968
ISSN: 0009-7322,1524-4539
DOI: 10.1161/01.cir.38.1.144