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 ?
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).
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 authors observed that acute cigarette smoking caused a shift of mitral blood flow from early to late diastole and a prolongation of isovolumetric relaxation; they thereby concluded that cigarette smoking, by affecting LV filling and isovolumetric relaxation, significantly impaired LV diastolic function independently of its role as a risk factor for coronary atherosclerosis.
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.
Diastolic transmitral Doppler parameters were measured by pulsed Doppler transducer: peak of early diastolic (E) and late diastolic (A) mitral flow velocities, E/A ratio, deceleration time E (DT) and isovolumetric relaxation time (IVRT).
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.
4 cm, ejection fraction--25%, normal basal segments, apical hypokinesis, apicolateral heavy hypokinesis, 2/3 distal septum akinesis, E/A ratio 2:1, deceleration time--150 msn, isovolumetric relaxation time - 80 msn, 1(+) mitral regurgitation, and normal valve structures were determined.