cardiac pressure volume loop Flashcards
what is the equation for work done by the ventricle muscle?
work= pressure x volume change
what is occurring during isovolumic contraction in the ventricle?
heart is still contracting without changing volume
what is occurring during isovolumic relaxation in the ventricle?
heart is relaxing without changing volume
what is occurring during the “mitral valve open to mitral valve close” phase in the cardiac cycle?
ventricle is filling with blood
there is an increase in pressure due to increase in passive tension as the ventricle muscle stretches
what is the “increase in passive tension” called?
preload
what is the end-systolic pressure volume relationship (ESPVR)?
the curve that describes that maximal pressure that can be developed by the ventricle at any given LV volume
what is the inverse of compliance?
elastance
what is the equation for compliance?
change in volume/change in pressure
in describing the ventricle filling, what does a high compliance/low elastance mean
that the ventricle is “easy” to fill
what happens to the ESPVR curve as inotropy (contactility) increases?
curve becomes steeper and shifts to the LEFT
what happens to the ESPVR curve as inotropy (contactility) decreases?
becomes flatter and shifts to the RIGHT
what does a steeper EDPVR slope mean regarding compliance
what is an example of when this could happen?
indicates decreased compliance
ex. in ventricular hypertrophy
what does a flatter EDPVR slope mean regarding compliance
what is an example of when this could happen?
indicates increased compliance
ex. dilated cardiomyopathy
what does end diastolic pressure volume relationship curve describe?
the passive filling curve for the ventricle (and thus passive properties of the myocardium)
after the ventricle reaches is end diastolic volume and the mitral valve closes, what occurs?
muscle begins to actively contract and pressure increases rapidly (isovolumetrically) until the aortic valve opens
