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Correct Answer - A
Ans. A: Isovolumic relaxation phase
Maximum coronary blood flow occurs during the phase of
isovolumetric ventricular relaxation phase Isovolumetric/isometric relaxation www.tgoop.com/IVRT
An interval in the cardiac cycle, from the aortic component of the
second heart sound, that is, closure of the aortic valve, to onset of
filling by opening of the mitral valve.
Ventricular pressure decreases to zero rapidly while aortic pressure
decreases only to 80 mm Hg i.e. it remains fairly high.
Therefore, intra myocardial compression of blood vessels is minimal and perfusion pressure is maintained fairly high.
So coronary blood flow rises sharply
Maximum coronary blood flow occurs during this phase
It can be used as an indicator of diastolic dysfunction.
Prolonged IVRT indicates poor myocardial relaxation.
A normal IVRT is about 70 ± 12 ms, and approximately 10ms longer
in people over forty years.
In abnormal relaxation, IVRT is usually in excess of 110ms.
With restrictive ventricular filling, it is usually under 60 ms
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