L4.1 Valve dysfunction Flashcards Preview

Cardio Phys > L4.1 Valve dysfunction > Flashcards

Flashcards in L4.1 Valve dysfunction Deck (13):
1

Valve features

  • Passive, works through pressure gradient
  • Ensure undirectional flow
  • Closure → creates heart sounds

2

Heart sounds

  • 1st: tri/bicuspid closing (start systole)
  • 2nd: semi-lunar closing (start diastole)

3

Isovolumetric relax/contract

  • Isovolumetric relaxation: same vol, both valve closed, pressure in V ↓
  • Isovolumetric contraction: same vol, both valve closed, pressure in V ↑

4

Valve lesions: Stenosis

  • Restricted opening of valve
    • ↑resistance → restricted flow
    • ↑pressure gradient
      • ↑PRESSURE in upstream chamber

5

Valve lesions: incompetence

  • Imperfect closure of valve
  • ↓fwd flow & ↑bkwd flow of blood (REGURGITATION)
  • ↑VOLUME in upstream chamber

6

What is turbulence?

  • Valve lesions causes turbulence
    • From high blood velocity
      • Results in murmurs

7

Turbulence with normal valves?

  • 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

Relationship b/w exercise & valve dysfunction

  • ↑demands of exercise exacerbate hemodynamic diifficulties of valve dysfunction

9

Rate of valve lesion onsets

May be v. quick or takes years

10

Consequence of heart attacks on valve lesions

  • Papilary muscles lack O2 → die → chordae tendinae detaches → valve broken

11

Aortic regurgitation

  • 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

Mitral regurgitation

  • 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

Mitral stenosis

  • ↑LA pressure (by ↑vol → hypertrophy of LA)