L12 - Chronic Mitral Valve Insufficiency

Question 1

List the major components of the mitral valve

Answer 1

1. Chordae tendineae
2. papillary muscles (medial and lateral)
3. Leaflets
4. Annulus

Any of these could be damaged and contribute to mitral insufficiency

Question 2

Where is the mitral valve located?

Answer 2

Between the LA and LV

Question 3

2 cardinal symptoms of severe chronic mitral insufficiency/regurgitation

Answer 3

• Exertional dyspnea
• fatigue
Same as AR (minus angina)

Question 4

Etiology of MV insufficiency due to :

1. leaflets
2. MV annulus
3. Chordae tendineae
4. Papillary mm

Answer 4

1. leaflets: shortened (rheumatic HD), redundant (myxomatous valves, prolapse), deformed or defective (endocarditis)
2. MV annulus - calcification or marfans
3. chordae - rupture (idio or endocarditis)
4. papillary - dysfunction or rupture (secondary to atherosclerotic CAD); malaligment (LV dilatation w/CHF due to systolic dysfunction)

Question 5

Etiology of MV prolapse

Answer 5

1.histology: myxomatous degeneration of varying amounts of leaflets seen
2. “idiopathic” probably is usually hereditary (autosomal dominant w/age-dependent
penetrance)
3. occasionally associated with and part of other disease processes, e.g. Marfan’s

Question 6

How does change in posture affect the auscultatory signs of mitral prolapse?

Answer 6

• sitting and standing: systolic click closer to S1 and murmur is prolonged
• squatting: click moves toward S2 and murmur is shorter.
  This is due to changes in LV volume and shape.
  Maneuvers that dec ventricular volume enhance leaflet redundancy, hasten prolapse, and move the click and murmur earlier in systole
  Inc LV dimensions has the opposite effect.
  Loudness is governed independently by LV systolic pressure

Question 7

What are symptoms in mitral prolapse?

- majority vs minority

Answer 7

1. majority - benign w/no sxs reflecting significant or serious hemodynamic or electrophysiologic abnormality
2. minority: hemodynamically significant MR requiring surgery; endocarditis; dysrhythmias; sudden cardiac death.

Question 8

Imaging of mitral valve prolapse
CXR
EKG
ECHO

Answer 8

CXR: enlarged left shadow plus signs of enlarged LA. No or only mild pulmonary vascular congestion (HF)
EKG: normal or NS-ST-T changes
sometimes arrhythmias
Echo: . very useful esp for assessing amount of regurg and LV function and confirming when PE is atypical or when Marfans is suspected

Question 9

T/F: a classic physical exam is sufficient for diagnosis of mitral valve prolapse

Answer 9

True

Question 10

Mitral regurg murmur

Answer 10

Mid-frequency, rectangular murmur taking up all of systole. Blowing sound best heard at apex with radiation to the axilla.
S1 is normal
S2 is single
three is a S3 gallop in diastole
both LV and LA enlarged
Murmur is caused by turbulent flow through incompetent mitral valve leaflets into the LA

Question 11

Patient history of chronic severe MR

Answer 11

A long asymptomatic period from onset of the murmur until onset of the typical symptoms of
slowly progressive exertional shortness of breath and exertional fatigue