Mitral Valve Disease (regurgitation and stenosis)

Question 1

How many leaflets does the mitral valve have and what is the purpose of them?

Answer 1

• Two: anterior and posterior
• Separates left atrium and left ventricle from each other
• During systole = valve closes = blood goes to aortic valve for circulation

Question 2

What is mitral valve regurgitation?

Answer 2

Valve does not close fully so blood leaks back into left atrium

Question 3

What happens during mitral valve regurgitation?

Answer 3

• Mitral valve prolapses, so when left ventricle contract, pressure is generated - blood pumped into aorta
• blood leak back into left atrium
• (usually chordae tendinea and papillary muscles prevent valve from prolapsing)
• in this case surrounding tissues are weak (MYXOMATAIS DEGENERATION)
• increase chordae tendiae length = rupture (common in posterior leaflet)
• larger valve leaflet area = hypertrophy and pressure

Question 4

What is mitral valve prolapse?

Answer 4

• one or both of mitral valve flap around, do not fold (stretch inward) into left atrium when left ventricle contracting (systole)
• back flow of blood into left atrium = mitral valve regurgitation

Question 5

Aetiology of mitral valve regurgitation?

Answer 5

Unsure but could be genetic disorders
- Marfan syndrome
- Ehlers Danlos Syndrome

Question 6

What are the signs/symptoms?

Answer 6

• systolic murmur = fold in atrium stopped suddenly by chordae tendinae
  -murmur = blood leaks back into left ventricle
• pt squats = murmur comes down and shorter (increased venous return so ventricles become larger = longer for leaflets to get forced into atrium when ventricle contracts)
• pt stands = clicks soon ,murmur longer (reduces venous return, less blood in ventricle, leaflet forced out early during contraction)

Question 7

Other causes?

Answer 7

• damaged papillary muscles by heart attack = papillary muscles cannot anchor chordae tendinae = leaflets flap: back flow of blood
• left sided heart sided = left ventricular dilation = stretch mitral valve ring = blood leak into left atrium
• rheumatic fever = inflammatory disease affect heart = chronic rheumatic heart disease= leaflet fibrosis (incomplete sal, blood leak through)–holosystolic murmur

Question 8

MVR can cause left sided heart failure

Answer 8

• left ventricle contracts, some blood pumped into left atrium
• increase pre load (blood drained into ventricle after contraction)
• left atrium and left ventricle volume overload
• compensation for a while = eccentric hypertrophy, new sarcomeres added on top = get larger both chambers
• this only lasts a while
  -eventually leaded to left sided heart failure

Question 9

What is mitral valve stenosis?

Answer 9

• common cause is rheumatic fever
• leaflets fuse together (commursal fusion) = mitral valve opening narrowed, harder for blood to flow from left atrium into left ventricle, volume of blood in left atrium goes up= high pressure in left atrium
• goes through fibrotic valve = make snap sound, diasystolic mumble (blood forced through small opening)

Question 10

Other causes of mitral valve stenosis?

Answer 10

• dilation (blood backs up into pulmonary circulation)
• lead to pulmonary congestion and oedema = difficulty breathing
• pulmonary hypertension = hard for right ventricle to pump blood to lungs
  -right ventricle hypertrophy = right sided heart failure

Question 11

Atrial fibrillation due to mitral valve stenosis?

Answer 11

• left atrium dilates, muscle wall stretches
• pacemaker cells irritated so right atrium and left atrium do not contract properly
• stagnant blood = atrium predicated = thrombosis dilated = thrombosis formation = gets into systemic formation

Question 12

Oesophagus compression and mitral valve stenosis?

Answer 12

• oesophagus compression = hard to swallow (dysphagia)
• atrium dilates and becomes larger

Question 13

Treatment?

Answer 13

valve repair/replacement