Diastolic Heart Failure

[Kaustikos]

I dunno if it's sources being wrong or Uworld but I can't seem to find a concrete answer regarding EDV/EDP/EF pertaining to isolated Diastolic HF

UWorld states that EDV and EF remain the same and only EDpressure increases. I look online/books and they say that the EDV actually decreases, EDp increases and EF may/may not remain the same and even decrease. So what's the truth?

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[John Lannister]

I dunno if it's sources being wrong or Uworld but I can't seem to find a concrete answer regarding EDV/EDP/EF pertaining to isolated Diastolic HF

UWorld states that EDV and EF remain the same and only EDpressure increases. I look online/books and they say that the EDV actually decreases, EDp increases and EF may/may not remain the same and even decrease. So what's the truth?

Using Lily: EDV decreases and EDP increase in diastolic HF, with preserved ejection fraction. (that's EF on a lower EDV though, mind you -i.e. decreased SV). The ventricular pressure is higher @ all diastolic volumes.

 

[sharklasers]

I dunno if it's sources being wrong or Uworld but I can't seem to find a concrete answer regarding EDV/EDP/EF pertaining to isolated Diastolic HF

UWorld states that EDV and EF remain the same and only EDpressure increases. I look online/books and they say that the EDV actually decreases, EDp increases and EF may/may not remain the same and even decrease. So what's the truth?

I'm just trying to think this through, since that would obviously help both of us remember it.

Diastolic HF is due to a stiff LV, commonly associated with hypertrophic cardiomyopathy.

With HCM, you have hypertrophy LV, which decreases the size of the chamber. Less blood enters the chamber. EDV decreases.

With a stiff LV, the compliance is decreased, which means that even though there is a smaller change in volume, there is a relatively larger change in pressure (remember, compliance = delV/delP --- this is decreased when delV is decreased relative to delP). So you have an increased in EDP.

HCM is not a problem with systole. The heart contracts just fine, it just fills less. EF stays the same. So although EDV decreases, ESV decreases proportionally so EF remains the same (remember, EF = (EDV-ESV)/EDV)

Hope this is correct, and if it is, hope this helps someone understand this better!

 

[addo]

It may be simplified but I thought systolic failure was a defect in the pumping ability of the heart, which results in decreased EF.
Diastolic failure is a problem with filling, but the heart has no problem in contractility and therefore has preserved EF. EDV might be decreased but the heart can have sufficient capacity in contractile force to decrease ESV to maintain EF.

I dont know... thats the way I see it. Apparently the distinction between pure systolic and pure diastolic failure is not really that common. I read most patients have an overlap between the two.

 

[John Lannister]

It may be simplified but I thought systolic failure was a defect in the pumping ability of the heart, which results in decreased EF.
Diastolic failure is a problem with filling, but the heart has no problem in contractility and therefore has preserved EF. EDV might be decreased but the heart can have sufficient capacity in contractile force to decrease ESV to maintain EF.

I dont know... thats the way I see it. Apparently the distinction between pure systolic and pure diastolic failure is not really that common. I read most patients have an overlap between the two.

Yeah, this is really test taking banter. In the real world it's probably combinations and management will not be determined by figuring out questions like these.

 

[Kaustikos]

I get the distinction between systolic/diastolic HF. But I see explanations for how the EDV changes and they both make sense. I'm not a fan of those pressure/volume curves honestly so I've been trying to get that down. I'm missing questions now not because I don't know it but because there seems to be discrepancies in what happens.

It's almost like Uworld likes to take snapshots of these diseases at certain time points but not really telling me that.

 

[MDSlacker]

All of the resources you are looking at are correct. The EDV could be decreased or normal. You have to think of everything as a continual process rather than just memorizing facts. Think about it.....

In the initial stages of diastolic heart failure the ventricles are stiff. Blood is able to flow into the heart and expand the ventricles but because they are stiff there is a higher pressure (increased EDP). Because this is the initial stage the ventricles are stuff but the increase in pressure is able to overcome this and the EDV is able to remain normal. When the heart pumps the EF also stays normal (no problem with contraction)

In the later stages of diastolic heart failure the ventricles become severely stiff. In this state the increase in pressure is not able to expand the ventricles enough and you can't fill the heart with a normal amount of blood and therefore the EDV decreases. Still no problem with contraction so EF stays normal.

Easy stuff.....