Getting Ea (arterial elastance) from the PV loop | NCLEX-RN | Khan Academy

Find out how to use the PV loop to draw the Ea (Arterial Elastance) line, and what it represents. Rishi is a pediatric infectious disease physician and works at Khan Academy. Created by Rishi Desai.
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[@mateouribe9956]

Hi. I love your videos. Can you give me some bibliography A.K.A articles about this. the sources from which you learned all this pv loop interpretation?

[@johannesdesilentio1035]

I think there is a misunderstanding in this video. The Ea line would represent the true arterial elastance only if the y axis component represented the change in arterial pressure that occurs with each heart beat. In reality, a change in arterial volume equal to the stroke volume does not change the arterial pressure from zero to Pes, it only changes from diastolic pressure to systolic pressure. You mention that we can assume the venous pressure is zero, but really you’re assuming that the arterial diastolic pressure is zero, which is far from true. The Ea as represented by the line you draw is a useful variable in physiology but it lumps together several physical properties of the aortic valve and arterial system. It has the units of elastance, but it does not represent the elastance of any actual structure. It is more like an imaginary elastic structure that would affect the behaviour of the LV in the same way that the real structures do.