cardiac pressure volume loop Flashcards

1
Q

what is the equation for work done by the ventricle muscle?

A

work= pressure x volume change

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2
Q

what is occurring during isovolumic contraction in the ventricle?

A

heart is still contracting without changing volume

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3
Q

what is occurring during isovolumic relaxation in the ventricle?

A

heart is relaxing without changing volume

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4
Q

what is occurring during the “mitral valve open to mitral valve close” phase in the cardiac cycle?

A

ventricle is filling with blood

there is an increase in pressure due to increase in passive tension as the ventricle muscle stretches

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5
Q

what is the “increase in passive tension” called?

A

preload

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6
Q

what is the end-systolic pressure volume relationship (ESPVR)?

A

the curve that describes that maximal pressure that can be developed by the ventricle at any given LV volume

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7
Q

what is the inverse of compliance?

A

elastance

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8
Q

what is the equation for compliance?

A

change in volume/change in pressure

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9
Q

in describing the ventricle filling, what does a high compliance/low elastance mean

A

that the ventricle is “easy” to fill

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10
Q

what happens to the ESPVR curve as inotropy (contactility) increases?

A

curve becomes steeper and shifts to the LEFT

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11
Q

what happens to the ESPVR curve as inotropy (contactility) decreases?

A

becomes flatter and shifts to the RIGHT

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12
Q

what does a steeper EDPVR slope mean regarding compliance

what is an example of when this could happen?

A

indicates decreased compliance

ex. in ventricular hypertrophy

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13
Q

what does a flatter EDPVR slope mean regarding compliance

what is an example of when this could happen?

A

indicates increased compliance

ex. dilated cardiomyopathy

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14
Q

what does end diastolic pressure volume relationship curve describe?

A

the passive filling curve for the ventricle (and thus passive properties of the myocardium)

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15
Q

after the ventricle reaches is end diastolic volume and the mitral valve closes, what occurs?

A

muscle begins to actively contract and pressure increases rapidly (isovolumetrically) until the aortic valve opens

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16
Q

what is the afterload?

A

the point when the blood pressure in the ventricle equals or exceeds the blood pressure in the aorta

17
Q

what word does this definition describe?

“volume of blood ejected by the ventricle in a single contraction”

A

stroke volume

18
Q

in what type of situation is stroke volume sensitive to afterload changes?

A

in a failing heart, normally SV is NOT greatly influenced by afterload

19
Q

define ejection fraction

A

fraction of end diastolic volume that is ejected out of the ventricle during each contraction
EF= SV/EDV

20
Q

in a healthy ventricle, what is the usual ejection fraction?

A

greater than .55

21
Q

low EF is usually indicative of what?

A

systolic dysfunction

22
Q

if the EF is lower than .2 what is the heart at risk for?

A

severe heart failure

23
Q

increased enotrophy does what to the EF?

A

increases it

24
Q

define preload

A

the EDV at the beginning of systole

25
what is preload and afterload measured in?
preload is in volume | afterload is in pressure mmHg
26
increasing aortic pressure does what to the amount of work that the heart has to do?
increases it
27
increasing stroke volumes will do what to the amount of work that the heart has to do?
increase it because they heart has to move more blood
28
increasing the preload will do what to the tension and stroke volume?
increase it
29
increasing ventricular afterload does what to stroke volume and ejection fraction?
it decreases stroke volume and ejection fraction
30
what does norepi do to: stroke volume ejection fraction contractility
increase SV can increase EF increase contractility
31
how does cardiomyopathy and heart failure normally effect CO
decrease it
32
how does infection and sepsis normally affect CO
increase cardiac output