Assessment of left ventricular relaxation by Doppler echocardiography. Comparison of isovolumic relaxation time and transmitral flow velocities with time constant of isovolumic relaxation.
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منابع مشابه
Assessment of left ventricular relaxation by Doppler echocardiography. Comparison of isovolumic relaxation time and transmitral flow velocities with time constant of isovolumic relaxation.
Isovolumic relaxation time (IVRT) and events of early transmitral flow measured by Doppler echocardiography were validated against the time constant of left ventricular relaxation (tau) in open-chest dogs. During increased inotropy (by isoproterenol infusion) at constant preload, enhancement of relaxation was indicated by a decrease in tau from 48 +/- 12 (mean +/- SD) to 33 +/- 5 msec (p = 0.04...
متن کاملComparison of Isovolumic Relaxation Time and Transmitral Flow Velocities With Time Constant of Isovolumic Relaxation
msec (p=0.04) with a concomitant decrease in IVRT from 74±18 to 38±8 msec (p=0.03). During decreased inotropy (by propranolol infusion) at constant preload, slowing of relaxation was indicated by an increase in T from 40±8 to 51±+13 msec (p=0.02) with a concomitant increase in IVRT from 71±+15 to 83+±21 msec (p<0.05). A significant correlation between changes in and changes in IVRT was found (r...
متن کاملRelation of left ventricular isovolumic relaxation time and incoordination to transmitral Doppler filling patterns.
OBJECTIVE To investigate factors during isovolumic relaxation that determine Doppler filling patterns in patients with left ventricular disease, and thus to identify the underlying mechanisms. DESIGN 85 patients (50 ischaemic heart disease, 35 left ventricular hypertrophy due to aortic stenosis) and 26 controls were studied with Doppler and M mode echocardiography and phonocardiography. 16 pa...
متن کاملQuantification of incomplete left ventricular relaxation: relationship to the time constant for isovolumic pressure fall.
We initially found that the fall in left ventricular pressure during isovolumic relaxation is exponential and therefore characterized by a time constant (T). To the extent that isovolumic pressure fall reflects myocardial events during relaxation, T indexes the time course of relaxation of the left ventricle. In isolated canine hearts sudden beat to beat loading changes from isovolumic to eject...
متن کاملDiscrepancies in the measurement of isovolumic relaxation time: a study comparing M mode and Doppler echocardiography.
Mitral valve cusp separation on M mode echogram, the mitral valve opening artefact, and the onset of forward transmitral flow recorded by Doppler echocardiography have all been taken to mark the end of isovolumic relaxation, while its onset has been taken either as the aortic closure sound (A2) recorded phonocardiographically or the aortic closure artefact determined by Doppler technique. Possi...
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ژورنال
عنوان ژورنال: Circulation
سال: 1990
ISSN: 0009-7322,1524-4539
DOI: 10.1161/01.cir.81.1.260