Step I Mitral Valve prolapse Uworld vs FA

[iA-MD2013]

FA 2011 pg 259: Mitral prolapse murmur is enhanced by maneuver that increase TPR (eg, squatting, hand grip)

Uworld - murmur disappears with squatting because increased preload --> increased LV EDV --> "facilitate proper closure of the otherwise oversized mitral valve leaflets"

I don't know what to believe 😕

 

[medking]

FA 2011 pg 259: Mitral prolapse murmur is enhanced by maneuver that increase TPR (eg, squatting, hand grip)

Uworld - murmur disappears with squatting because increased preload --> increased LV EDV --> "facilitate proper closure of the otherwise oversized mitral valve leaflets"

I don't know what to believe 😕

I think it has to do with phases.

Uworld one seems to be talking about instantaneous effects of squatting while FA is talking more about delayed effects.

Anyway, I'm probably wrong and there is a high likelihood that there is a more scientific explanation. Lol.

 

[iA-MD2013]

Hmm interesting...I never thought about it as an issue of timing.

I was trying to reason it out and ended up just assuming that in some people the murmur increases while in others it doesn't...is that reasonable?

 

[medking]

Hmm interesting...I never thought about it as an issue of timing.

I was trying to reason it out and ended up just assuming that in some people the murmur increases while in others it doesn't...is that reasonable?

After doing a very, very, quick google search, I'm just going to go with uworld on this one until someone/something tells me otherwise.

Increasing/decreasing LV EDV (correlates with size of ventricles/amount of blood that will move across valves) seems to be the key with murmurs.

From what I've gathered, squatting increases LV EDV. So with MVP (like uworld says), squatting decreases the murmur d/t better overlap of the valve.

Btw, does squatting increase TPR in the first place? In my head, where I have a tendency to oversimplify things it goes something like this: squat---->"block" vessels--->blood backs up----->increase in pressure/resistance, so it sounds good, BUT, from the quick google search I think I saw something like squatting decreases TPR d/t the increase in BP (compensation). So I don't even know if FA has its facts straight on this one.

I don't know, haha. But one thing is for sure, you've stumped a good number of people.

 

[mrmandrake]

Look at Goljan RR Path 3rd edition page 179. I think I'm going to go with his definition.

FA simplifies it by saying that the murmur is enhanced by squatting but if you look in UpToDate, there are multiple variables that change with various positions. The click is enhanced by squatting and hand grip but the duration of the murmur in relation to the duration of systole is decreased.

I think what's important is the onset of the murmur in relation to S1 and S2. When squatting, it moves closer to S2. When standing, it is closer to S1. This is explained on the RR Path page mentioned above.

 

[medking]

I guess squatting does increase TPR and this is why kids with TOF squat to help with symptoms. Or that's what they say.

I am officially super confused now, lol.

 

[levi2613]

If anyone's still stuck on this, FirstAid posted a correction on their errata page: http://firstaidteam.com/wp-content/uploads/FA-Step-1-2011-errata-110415.pdf

Hopefully it helps!