Lecture 29: Valve Disease Overview Flashcards Preview

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Flashcards in Lecture 29: Valve Disease Overview Deck (13):

What are key principles of valve disease?

Valve disorders place an additional burden on the heart and circulation
Any valve can be affected


What are general concepts of normal valve function?

1. designed to provide competent and unobstructed partitioning of blood flow between cardiac chambers
2. opens efficiently without obstruction
3. close (coapt) fully without allowing regurg


What are the two types of valvular disorders?

1. Stenosis = pressure load
-doesn’t open properly
2. Regurgitation = volume load
-doesn’t close properly
These two can be mixed (you can have both stenosis and regurg)


What are the two most common valvular disorders?

The ones affecting mitral and aortic valve
-most common in adult population because left side is less compliant
Pulmonic and tricuspid is possible but not as common in adult population


How should we think about valves?

As part of the chamber they serve as a gate to
Think of MV as part of LV
-stretching of the LV will fuck with mitral valve and lead to MR
Think of aortic valve as part of aorta
-enlargement of aorta leads to AR in addition to leaflet disease


What must be understood for each type of valve disorder?

1. The nature of the burden on cardiac chamber(s)
2. The mechanism of impairment of cardiac performance (what’s wrong)
3. The cardiovascular adaptive responses
i. acute
4. How the underlying disorder progresses
ii. chronic
5. How the adaptive responses fail and heart failure develops


What is the function of the valve in systole and diastole?

Systole: chamber pressure increases
i. requires substantial myocardial metabolic activity
Diastole: chamber pressure decreases
i. diastole requires ATP too


What are the key characteristics of stenosis?

Requires increased pressure in chamber UPSTREAM of an affected valve
-so heart’s ability to cope is determined by upstream chamber’s ability to compensate
Impairs ability to increase CO
Generally a chronic disorder


What are the key characteristics of regurgitation?

Defined as backward flow into the chamber upstream from the affected valve
-so heart’s ability to cope determined by BOTH upstream/downstream chambers
Places volume load on BOTH downstream and upstream chamber
CO is less impaired (fairly preserved)
Comes in acute and chronic varieties
Aortic and mitral are distinct entities
MR = increased diastolic wall stress
AR increased diastolic + systolic wall stress


What is impaired in MR?

Increased diastolic wall stress


What is impaired in AR?

Increased diastolic AND systolic wall stress


What happens with stenotic valves in exercise?

Impaired ability to increase CO


What happens with regurgitant valves when you exercise?

Often no impaired CO because SV can be repartitioned