isovolumic relaxation

(redirected from isovolumetric 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.
References in periodicals archive ?
In the present study, the isovolumetric relaxation time (IVRT) showed mean and SD of 102 [+ or -] 20.
Reduced systolic and diastolic functions with an ejection fraction of 51% and delayed isovolumetric relaxation time (IVRT) of 102 ms were determined, respectively.
The LV diastolic function has been evaluated using the Pulse Wave (PW) Doppler transmitral flow applied in a 4-chamber apical view where the E and A wave velocities, E/A ratio, deceleration time (DT) and isovolumetric relaxation time (IVRT) were calculated.
The interval 'a' from cessation to onset tricuspid valve inflow is equal to the sum of isovolumetric contraction time (ICT), ejection time, and isovolumetric relaxation time (IRT).
Isovolumetric Relaxation Time (IVRT) was not significantly different.
The isovolumetric relaxation time was measured at the five-chamber apical view as follows: Pulse Doppler was used to measure the frequency spectrum at the systolic and diastolic phases.
The diastolic dysfunction parameters; ratio of transmitral flow velocities during early and late filling (E/A ratio), ratio of transmitral flow velocity to mitral annular velocity during early filling (E/Em ratio), deceleration time (DT), and isovolumetric relaxation time (IRVT) were recorded by Doppler echocardiography.
Isovolumetric relaxation time (IVRT) was determined as the interval between the end of the aortic outflow and the start of the mitral inflow signal.
Doppler echocardiography was used for estimation of LV mitral early (E) and late (A) inflow velocities, their ratio (E/A), isovolumetric relaxation time and E-wave deceleration time and pulmonary artery pressure.
Also, isovolumetric relaxation time of the right ventricle (IVRTR) was obtained as the time interval from the cessation of RV outflow to the onset of tricuspid valve inflow.
The following parameters were used to evaluate diastolic function: isovolumetric relaxation time, transmitral early to late filling flow velocities (E/A) ratio, deceleration time E, pulmonary vein Doppler findings and color mitral flow propagation velocity.
As expected, HCM patients had smaller LVs, thicker interventricular septal thickness and LV posterior walls, increased LV ejection fractions and longer E wave deceleration time and isovolumetric relaxation times than controls.