Heart Failure Flashcards
Definition of heart failure
Structural or functional cardiac disorder that impairs the ability of ventricles to eject blood (forward failure) or fill with blood (backward failure) or both.
CO=?
SVxHR
What three things affect SV?
Preload, afterload, contractility.
How to calculate stroke volume?
End diastolic volume - end systolic volume
Ejection fraction
Stroke volume / end diastolic volume
Effect of increasing preload on PV loop
ESV stays pretty much the same, but EDV moves to the right along the EDPVR. So, stroke volume increases.
Effect of increasing contractility on the PV loop?
ESPVR curve rotates up. So while EDV remains the same, ESV decreases and SV increases.
Effect of increasing afterload on the PV loop?
ESV moves up along the ESPVR curve, so ESV increases and stroke volume decreases. EDV remains the same.
Systolic heart failure, and symptoms
Decreased cardiac output, decreased ejection fraction.
<50%. Dizziness, fatigue.
What counts as reduced ejection fraction?
<50%
Diastolic heart failure
Elevated LV and RV end-diastolic pressures.
Usually normal EF.
Etiology of systolic heart failure
Impaired contractility from:
CAD/ MI
Chronic volume overload from mitral regurg, aortic regurg.
Dilated cardiomyopathy.
Increased afterload from:
Aortic stenosis
Hypertension
Etiology of diastolic dysfunction
Preserved EF but impaired diastolic filling from: LV hypertrophy Restrictive cardiomyopathy Myocardial fibrosis Pericardial tamponade.
Basically, an alteration of structural properties.
Effect of systolic heart failure on PV loop
Decrease in contractility rotates ESPVR to the right. So ESV increases. Heart dilates to maintain SV (EDV increases in a process called remodeling). When remodeling occurs, filling pressure needs to increase, so signs of congestion occur down the line.
Remodeling
Heart dilation in systolic heart failure to compensate for decrease in SV from decrease in contractility. EDV increases as a result.
