Basic phys question: pulse pressure in AS and AI

[wAyRadikull]

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I've having a pretty tough time recalling why there is a narrowed pulse pressure in aortic stenosis and widened pulse pressure in aortic insufficieny. So if someone could just quickly break it down for me in terms of systolic and diastolic pressure that would be extremely helpful.

I did phys quite sometime ago and reading through BRS phys now. I've having a hard time understanding this concept for some reason. I got it while I was doing phys in med school but for some reason, its not clicking. I also looked through Kaplan phys but didn't get a satisfactory answer. Also, if you have a source I can look into, that would be helpful as well. Thanks.

 

[sd1984]

Please correct me if I am wrong:


Aortic Stenosis, think of a narrowed hardened valve, the LV will have to generate a higher pressure to overcome the Aortic Pressure for the Valve to open, thus consuming more ATP - contributes to Clinical Signs and also to Diamond Shape, denoting the LV raising its pressure against a stenotic valve.

Insufficiency is the regurgitant flow due to an incompetent valve, the regurgitant flow increases pressure in the back flow chamber. Ie. Aortic Insuff increases LVESP. Excess Volume = Increase in Pressure = Increase in Myocardial Cell O2 Consumption due to stretching = Problems

 

[Rendar5]

for AI, just think of it this way. The heart pumps out as it normally does, so systolic is not having a major issue. maybe it's normal, maybe it's a bit higher because there's less forward flow. But diastolic? the heart cannot maintain a normal distolic because there's a way for all that pressure to leak out (due to backwards flow). Think of it like this. Is water gonna reach the top of the empire state building if you just smashed open the pressure valves in the basement? Lower than normal diastolic plus normalish systolic = widened PP.

 

[Keyser112]

for AI:

when the ventricle contracts it flows out normally. however because of the AI blood will leak back into the ventricle.
this has 2 consequences: 1st, diastolic pressure will drop because there is less blood in the aorta. 2nd, end diastolic volume in the ventricle will now increase so on the next stroke the stroke volume will be increased leading to increased systolic pressure.

higher systolic pressure and decreased diastolic pressure = widened PP.

 

[wAyRadikull]

Thanks for the responses guys. Its all clear now haha 👍