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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References in periodicals archive ?
The isovolumic contraction time (IVCT: interval between the end of the A' wave and the beginning of the S' wave) and the isovolumic relaxation time (IVRT: interval between the end of the S' wave and the beginning of the E' wave) were measured for both sides of the mitral annulus and lateral side of the tricuspid annulus on the tissue Doppler.
Echo Doppler parameters of diastolic function are isovolumic relaxation time, mitral inflow parameters.
The mitral valve inflow pattern (E wave, A wave, E-wave deceleration time, E/A ratio, and isovolumic relaxation time) was measured by pulsed wave Doppler.
The increase in MPI in the WD group is likely due to abnormal diastolic function as indicated by both a prolonged period of isovolumic relaxation (Figure 2(b)) and a decrease in mitral inflow Vp (Figure 2(c)).
The myocardial performance index (Tei index) is an echocardiographic/Doppler index that combines systolic and diastolic function and is calculated as isovolumic relaxation time plus isovolumic contraction time divided by ejection time.
They also showed increases in LV filling pressure (E/E' and E/Vp ratios), isovolumic relaxation time (IVRT), and myocardial performance index (Tei index of global cardiac function) (Table 1).
The measured steady-state hemodynamic parameters include derivative of pressure (dp/dtmax, dp/dtmin) and isovolumic relaxation constant (Tau).
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 0.05).
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.
Analysis of these data showed that the procedure significantly improved left ventricular mass (enlargement of the muscle tissue that makes up the heart's main pumping chamber), the E/A ratio (the proportion of blood the heart pumps out in one beat) and pump filling action (isovolumic relaxation time or the ability of the heart to relax after a contraction).
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.