Isolated diastolic heart failure

[OrthoRehab33]

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65yo pt complains of exertional dyspnea- has not seen a physician in 10 yrs. BP 170/90 pulse is 80/min
PE reveals bilateral lung crackles. What changes are seen in isolated diastolic heart failure (LVEDP, LVEDV, LV ejection fraction)?
It says that LVEDP= increased; LVEDV= normal; LVEF= normal
None of the option choices gave LVEDV being reduced--but that's what I thought since the heart is having difficulty filling- but I knew it wouldnt be increased, but I suspected LVEF to be decreased since he seems like he's decompensated with fluid in his lungs. Anyone get why EJ is normal? It says the LVEDP continues to rise as heart attempts to maintain near normal SV and CO. Decompensation occurs when increased LVEDP causes pulmonary edema and dyspnea. Which makes sense but I just thought decompensation would decrease EJ causing increased End Systolic Volume that transmits the pulmonary circuit

 

[zhopv10]

Diastolic failure is defined as: increased end diastolic pressure, normal end diastolic volume, with preserved EJ (defining feature of systolic failure). So a key principle I think here is that this is caused from decrease in compliance of the LV, unlike systolic failure which often leads to increased compliance (fluid overload) This can be caused from LV thickening from aortic stenosis hypertension, aging, whatever. So diastolic function is determined by the relative end diastolic volume in relation to end diastolic pressure and is independent of systolic function by the LV. So with less compliance you are trying to get the same amount in to maintain output so pressure then has to increase. This makes it more difficult to get blood into the left ventricle so pressure increases in the left atrium to be able to drive the blood into the left ventricle and this pressure is transmitted back to the lungs and you get pulmonary hypertension/edema. So unlike systolic dysfunction where end systolic volume is increasing and you are getting volume overload leading to fluid back up into the lungs, here you are getting the pressure gradient (not fluid) backing up into the lungs. Again, by definition EJ fraction has to be normal otherwise that is systolic failure. It's kinda weird cause in reality they often occur together so that is why the stem specified isolated. The fact that they often are mixed actually makes it tough to precisely dx/define for trials.

As for LVEDV reducing, that is assuming no compensatory response. The heart will do all it can to maintain CO so the atria here will work harder to get that same volume in even if it means higher pressure. It seems like it would be failing due to the fluid backup but in this case it is a pressure back up, the pressure is higher so the atria need to be at higher pressure to get the fluid in this pressure goes to the lungs since there is no valve between the mitral and pulmonary vasculature and that increased pressure pushed more fluid out into the interstitium (hydrostatic pressure).

So the decompositions different, one the pump is failing and fluid is backing up behind it (systolic) the other the pump is working really hard at higher pressure because the ventricle is less complaint and that increased pressure is transmitted through the system and gets to the point where it pushes fluids out into the lungs (diastolic)

Hope that helps


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[OrthoRehab33]

Awesome explanation, thanks!

 

[zhopv10]

Oh a quick addition too, so I mentioned how the EDV stays the same to maintain CO but didn't really mention why. Ventricular EDV approximates preload which is dependent on venous tone and circulating blood volume (venous return curves). These are not effected in this situation and since CO is not decreased that side of things doesn't affect the venous return either so it stays the same. The heart pumps what comes into it, anything less and it is in systolic heart failure (again see cardiac function curves). Just thought I'd throw that integration in there quick, hope it's helpful.


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[Phloston]

The terms diastolic vs systolic heart failure are outdated. I just came off a cardiology term and they were pedantic/OCD about this.

Heart failure with preserved ejection fraction = was once called diastolic heart failure

Heart failure with reduced ejection fraction = was once called systolic heart failure

Reason is because heart failure frequently has elements of both, so it's misleading/actually incorrect to label one's disease as strictly systolic vs diastolic based merely on EF.

The reason LVEDP is increased is because more lateral wall stress is needed to expand a non-compliant myocardium.

To specifically address your line of reasoning:

1) Remember EF is normal

2) So if you posit that LVEDV should be low, yet EF is normal, that would mean LVESV should be low, which we know wouldn't happen because contractility isn't increased.

 

[zhopv10]

Thanks for posting this! In the back of my mind I was remembering something our teachers said about this stuff and HF-PEF and that was it! (The terminology).


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