isovolumic relaxation

i·so·vol·u·mic re·lax·a·tion

that part of the cardiac cycle between the time of aortic valve closure and mitral opening, during which the ventricular muscle decreases its tension without lengthening so that ventricular volume remains unaltered; the heart is never precisely isovolumetric (vs. isovolumic) except during long diastoles with a midiastolic period of diastasis.
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Mitral 'E' velocity (peak velocity of early mitral flow), mitral 'A' velocity (peak velocity of late mitral flow), E/A ratio (velocity of diastolic early filling wave/velocity of late filling wave), annular tissue motion (denoted by e'), E/e' ratio, Isovolumic Relaxation Time (IVRT), deceleration time of mitral 'E' curve (DT of E) and left atrial diameter was calculated to find the presence of left atrial enlargement.
The transmitral E and A waves velocities, E/A ratio, E wave deceleration time (DT), and the isovolumic relaxation time (IVRT) were measured using the conventional two dimensional and pulsed wave Doppler.
The results for right heart showed that Z scores for peak E velocity, peak A velocity, pre- ejection period, isovolumic relaxation time, myocardial performance index and isovolumic contraction time were significantly different (pless than 0.
The correlations between isovolumic relaxation time, P wave duration and LA size and coronary ectasia may reflect, indirectly, the element of diastolic dysfunction in this cohort.
We measured left ventricle Ejection Fraction (EF) and Fractional Shortening (FS) to survey left ventricle systolic function, and left ventricle Isovolumic Relaxation Time (LV IVRT) and also Early rapid filling/Atrial contraction (E/A ratio) in mitral valve blood flow to survey left ventricle diastolic function.
Isovolumic relaxation time and isovolumic contraction time from the basal part of the left ventricle, myocardial rate during the systole, myocardial rate during the erly diastole, the rate during the late diastole, ejection time, isovolumic contraction acceleration and acceleration of the ventricle at the time of isovolumic contraction were measured.
8 in individuals >55 years, DT >220 ms, IRT >100 ms; pseudonormal: 1 < E/A < 2,150 ms < DT < 200 ms, IRT <100 ms; restrictive filling, E/A >2, DT <150 ms, IRT <60 ms, where E is the peak E-wave velocity and A is the peak A-wave velocity of the mitral inflow, DT is the deceleration time of the E wave, and IRT is the left ventricular isovolumic relaxation time (13).
Both the isovolumic relaxation time and the systolic contraction velocity showed improvements that were significantly greater in the valsartan group, compared with the control patients.
They found on Doppler derived indices of diastolic function, a significant prolongation of the isovolumic relaxation time (IVRT), increased A wave and reduced early diastolic mitral flow velocity/late diastolic mitral flow velocity ratio.
Mitral E velocity (ME), mitral A velocity (MA), mitral E wave deceleration time (MEDT), and LV isovolumic relaxation time (IVRT), defined as time period between the termination of aortic systolic wave and beginning of ME, were measured by locating the sampling volume cursor of pulsed Doppler in the apical four chamber position at 5 mm above the mitral leaflets tips.