Isovolumic relaxation time (IVRT) is an interval in the

cardiac cycle The cardiac cycle is the performance of the human heart from the beginning of one heartbeat to the beginning of the next. It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following ...

, from the aortic component of the second

heart sound Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut. In cardiac auscultation, an examiner may use a stet ...

, that is, closure of the

aortic valve The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. Th ...

, to onset of filling by opening of the mitral valve."Inductance cardiography (thoracocardiography): A novel, noninvasive technique for monitoring left ventricular filling". ''Journal of Critical Care'', Volume 14, Issue 4, Pages 177–185 It can be used as an indicator of

diastolic dysfunction Heart failure with preserved ejection fraction (HFpEF) is a form of heart failure in which the ejection fraction – the percentage of the volume of blood ejected from the left ventricle with each heartbeat divided by the volume of blood when the l ...

. It can be measured by simultaneous

Doppler echocardiography Doppler echocardiography is a procedure that uses Doppler ultrasonography to examine the heart. An echocardiogram uses high frequency sound waves to create an image of the heart while the use of Doppler technology allows determination of the spee ...

and M-mode sonography, or better still, by simultaneous

phonocardiogram A phonocardiogram (or PCG) is a plot of high-fidelity recording of the sounds and murmurs made by the heart with the help of the machine called the phonocardiograph; thus, phonocardiography is the recording of all the sounds made by the heart ...

and transmitral Doppler.anaesthetist.com >Diastolic dysfunction
Lara Hopley and Jo van Schalkwyk. Date of last update: 2009-06-05 Prolonged IVRT indicates poor myocardial relaxation. A normal IVRT is about 70 ± 12 ms, and approximately 10 ms longer in people over forty years. In abnormal relaxation, IVRT is usually in excess of 110 ms. With restrictive ventricular filling, it is usually under 60 ms.

References

{{Reflist Cardiovascular physiology

See also

References