Lecture 29: Valve Disease Overview

Question 1

What are key principles of valve disease?

Answer 1

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

Question 2

What are general concepts of normal valve function?

Answer 2

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

Question 3

What are the two types of valvular disorders?

Answer 3

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)

Question 4

What are the two most common valvular disorders?

Answer 4

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

Question 5

How should we think about valves?

Answer 5

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

Question 6

What must be understood for each type of valve disorder?

Answer 6

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

Question 7

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

Answer 7

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

Question 8

What are the key characteristics of stenosis?

Answer 8

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

Question 9

What are the key characteristics of regurgitation?

Answer 9

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

Question 10

What is impaired in MR?

Answer 10

Increased diastolic wall stress

Question 11

What is impaired in AR?

Answer 11

Increased diastolic AND systolic wall stress

Question 12

What happens with stenotic valves in exercise?

Answer 12

Impaired ability to increase CO

Question 13

What happens with regurgitant valves when you exercise?

Answer 13

Often no impaired CO because SV can be repartitioned