L4.1 Valve dysfunction Flashcards
1
Q
Valve features
A
- Passive, works through pressure gradient
- Ensure undirectional flow
- Closure → creates heart sounds
2
Q
Heart sounds
A
- 1st: tri/bicuspid closing (start systole)
- 2nd: semi-lunar closing (start diastole)
3
Q
Isovolumetric relax/contract
A
- Isovolumetric relaxation: same vol, both valve closed, pressure in V ↓
- Isovolumetric contraction: same vol, both valve closed, pressure in V ↑
4
Q
Valve lesions: Stenosis
A
- Restricted opening of valve
- ↑resistance → restricted flow
- ↑pressure gradient
- ↑PRESSURE in upstream chamber
5
Q
Valve lesions: incompetence
A
- Imperfect closure of valve
- ↓fwd flow & ↑bkwd flow of blood (REGURGITATION)
- ↑VOLUME in upstream chamber
6
Q
What is turbulence?
A
- Valve lesions causes turbulence
- From high blood velocity
- Results in murmurs
- From high blood velocity
7
Q
Turbulence with normal valves?
A
- From ↑CO relative to body size
- e.g.:
- Children (growing → ↑CO)
- Fever (↑CO to skin to lose heat)
- Anemia (↑CO → pump more blood for same O2 dose)
8
Q
Relationship b/w exercise & valve dysfunction
A
- ↑demands of exercise exacerbate hemodynamic diifficulties of valve dysfunction
9
Q
Rate of valve lesion onsets
A
May be v. quick or takes years
10
Q
Consequence of heart attacks on valve lesions
A
- Papilary muscles lack O2 → die → chordae tendinae detaches → valve broken
11
Q
Aortic regurgitation
A
- Blood falls back into LV during diastole
- LV vol overload
- Eccentric cardiac hypertrophy
- ↑PP (more blood delivered in systole to compensate)
- Ejection fraction normal (↑ in SV & EDV)
12
Q
Mitral regurgitation
A
- LV contraction results in blood entering aorta & LA during systole
- LV vol overload (need to pump blood into aorta & LA)
- LA ↑vol during systole (blood from LV)
- LA & LV enlargement
- Enlargement of LA may compress oesophagus → troubles swallowing
- Ejection fraction normal (↑ in SV & EDV)
13
Q
Mitral stenosis
A
- ↑LA pressure (by ↑vol → hypertrophy of LA)
