E/e' ratio,

E/e' ratio

E/e´ ratio

To derive the E/e´ ratio one must divide the maximum velocity of the E-wave of mitral valve inflow by the maximal velocity of E. In normal individuals the E/e´ ratio is <8. In the presence of diastolic dysfunction / impaired relaxation, e´ will be rather low. In contrast, the E-wave increases with elevated filling pressures. Thus the E/e´ ratio will increase in the presence of diastolic dysfunction.

 An E/e´ratio >15 is highly suggestive of elevated filling pressures.

The ratio may be employed to directly estimate filling pressure by using the following formula:

Mitral Inflow — Reference values

	16- 20 years	21- 40 years	41- 60 years	> 60 years
IVRT (ms)	50 ± 9	67 ± 8	74 ± 7	87 ± 7
DT (ms)	142 ± 19	166 ± 14	181 ± 19	200 ± 29
A duration	113 ± 17	127 ± 13	133 ± 13	138 ± 19
E/A	1.88 ± 0.45	1.53 ± 0.4	1.28 ± 0.25	0.96 ± 0,18

Table of normal values/Ranges for individual patterns of diastolic dysfunction

Ref:

https://123sonography.com/ebook/assess-diastolic-function