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Old 02-02-2012
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Default Aortic Regurg help (AR)

I was doing a UWorld question where they asked in patient with AR what maintains the cardiac output (CO)?

Acute AR -> Increased heart rate will do it

Chronic AR -> Increased Preload + eccentric LV hypertrophy will maintain the CO and bring heart rate back to normal

My confusion is the Chronic AR. AR causes blood to go back into LV during diastolic phase, yet how can and eccentric heart pump enough blood to maintain the "normal" CO? Wouldn't an eccentric heart have a hard timing pump because of volume overload that it causes systolic dysfunction? And only way to get that normal CO would be to maintain the increased heart rate?
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Old 02-02-2012
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i m not sure but what i think is

in chronic AR -only way by which heart can deal with increased preload will be by hypertrophy of its walls(to pump the extra blood) .so initially hypertrophy will help in maintaining the CO but later due all the hypertrophy diastolic dysfunction will ensue
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Old 02-02-2012
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Quote:
Originally Posted by gear2d View Post
AR causes blood to go back into LV during diastolic phase, yet how can and eccentric heart pump enough blood to maintain the "normal" CO? Wouldn't an eccentric heart have a hard timing pump because of volume overload that it causes systolic dysfunction? And only way to get that normal CO would be to maintain the increased heart rate?


eccentric heart hypertrophy---- is just heart hypertrophy that is not in a well rounded manner...

hypertrophied heart=== hearts compensation to pump out more STRONGLY...
hence maintains CO ... (eventually will lead to CCF depending on the severity of AR)


increased CHRONIC heart rate=== heart is contracting alot.. but doesnt hv enough time to fill.. so that cannot compensate for CO long term




hope that helps
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Old 02-02-2012
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which q is that??
can u give us the no.
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