aortic regurgitation

[eur]

anyone that can help me with understanding this:
In aortic regurgitation, the pulse pressure increases due to increased
systolic aortic pressure and decreased diastolic pressure. I understand
that since blood is coming back to the left ventricle in this disease, then
there will be an increase stroke volume, and therefore increased systolic
pressure. But why does diastolic pressure decrease? I read that the
increased volume in the left ventricle causes this decrease in pressure, but
how is this so? Is it because of the end systolic volume/ end diastolic
volume vs. pressure curves? Is there some physics law that says an increase
in volume causes a decrease in pressure thats applied to the cardiovascular
system? (btw does p1v1=p2v2 apply to the cardiovascular system?)

thanks

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[Taus]

I think you are looking too far into the pressures in the heart...instead of the arterial pressures. If the blood has an easy time returning back through the valve it just came out of, the resting diastolic (arterial) pressure past that valve is not gonna be very high. Without even considering the systolic pressure, the pulse pressure has already widened.

 

[nrosigh]

But why does diastolic pressure decrease?

The diastolic pressure is lower because the blood falls right back into the ventricle! You don't need any physics for this.

Normally, the closed aortic valve prevents blood from pouring right back into the ventricle. If the aortic valve is incompetent, then there is nothing to prevent this backflow.

 

[eur]

Ahh i see thanks guys...ive been thinking of the pressures in terms of the heart when i need to be thinking of systolic/diastolic pressures in terms of the aorta .

Thanks