ScholarRX: Mitral Valve Disease

Question 1

what is mitral valve prolapse?

Answer 1

aka clock-murmur syndrome, floppy valve syndrome or Barlow syndrome

a condition in which the heart’s mitral valve doesn’t close tightly

mitral valve prolapse occurs when the two mitral leaflets and their attached chordae tendinae lose strength and the leaflets begin to balloon (prolapse) into the left atrium during systole

prolapse of the mitral valve leaflets into the LA doesnt usually cause problems but it can eventually lead to back flow of blood into the LA during systole = mitral regurgitation

Question 2

what is heart failure?

Answer 2

a deficit between the demands of the body and the heart’s ability to pump blood to keep up with them

if the backflow of blood into the left atrium from mitral regurgitation becomes severe enough, it can lead to a lack of oxygen and other nutrients getting to the various tissues in the body and cause heart failure

Question 3

what causes mitral valve prolapse?

Answer 3

1. myxomatous degeneration**
2. connective tissue diseases
3. other mitral valve disease

Question 4

what is myxomatous degeneration?

Answer 4

too much disorganized connective tissue in the middle layer of the valve leaflets and in the chordae tendineae

this can cause mitral valve prolapse because excess connective tissue causes the leaflets to thicken, the chordae tendineae to weaken, and the ring around the mitral valve to which the leaflets anchor (the annulus)to widen

we don’t know why myxomatous degeneration happens but it’s thought to be caused by sporadic genetic mutations, with some cases having a familial genetic component

Question 5

which connective tissue diseases can cause mitral valve prolapse?

Answer 5

1. Marfans
2. Ehlers-Danlos
3. osteogenesis imperfecta

Question 6

which diseases of the mitral valve can lead to mitral valve prolapse?

Answer 6

1. infective endocarditis –> can scar both the mitral valve leaflets and chordae tendineae, weakening both structures and causing MVP
2. tearing of the papillary muscles that connect the chordae tendineae with the left ventricular wall can weaken the mitral leaflet’s ability to resist the left ventricular pressure during systole, allowing it to prolapse –> papillary muscle rupture can be caused by MI or car accident
3. RF –> can cause inflammation that allows the mitral valve leaflets to stretch

Question 7

what is the most common cause of MVP and how does it usually happen?

Answer 7

myxomatous degeneration

usually caused by sporadic genetic mutations

Question 8

what are the signs of mitral valve prolapse?

Answer 8

mid-systolic click

this click is believed to be caused by the “snapping” of the mitral chordae tendineae when a leaflet prolapses into the left atrium during systole

Question 9

how does the timing of the click heard during mitral valve prolapse change?

Answer 9

timing of the click changes with how much the left ventricle is being filled –> ↓ LV volume = earlier click, ↑ LV volume = later click

the click will come earlier when the patient bears down (Valsalva) or stands (both lead to a smaller LV volume)

click will come later when the patient squats (larger LV volume)

Question 10

what are the symptoms of MVP?

Answer 10

1. SOB
2. palpitations
3. exercise intolerance
4. dizziness
5. anxiety disorders

most patients with MVP will have no symptoms at all and the symptoms that do show are nonspecific

Question 11

what is the most common presentation of MVP?

Answer 11

no symptoms at all

usually a secondary finding

Question 12

how do you diagnose MVP?

Answer 12

echocardiogram

echocardiogram will show at least one of the mitral valve leaflets prolapsing into the left atrium ≥2 mm above the level of the mitral annulus.

doppler echocardiography is also used to determine if there is any mitral regurgitation present and, if so, the extent of the backflow

Question 13

how do you treat MVP?

Answer 13

control the symptoms with reassurance that’s it’s benign and lifestyle changes like:

1. aerobic exercise
2. avoid caffeine, alcohol, fatigue and stress

if patients have little to no mitral regurgitation, they do not need regular surveillance of
their MVP –> if MVP has deteriorated to mitral regurgitation, medications or surgery may be
indicated based on the severity of the regurgitation, the heart’s ability to pump blood
into systemic circulation, and the patient’s symptoms.

Question 14

How far above the annulus must at least one mitral leaflet bulge on
echocardiography to diagnose MVP?

Answer 14

2 mm

Question 15

Mitral valve prolapse is usually due to which mechanism?

Answer 15

an excess of disorganized connective tissue = myxomatous degeneration

disorganized connective tissue is found in the spongiosa layer of the valve leaflets

Question 16

A patient presents for a yearly exam with no concerns. On heart exam, they are found to have a mid‐systolic click. What movements and the associated change in timing of the click correspond to mitral valve prolapse?

A. Hand clenching causing a later click

B. Inspiration causing an earlier click

C. Squatting causing an earlier click

D. Standing causing a later click

E. Valsalva causing an earlier click

Answer 16

E. Valsalva causing an earlier click

Valsalva causes an increase in intrathoracic pressure, which increases the pressure the left ventricle must push against and therefore decreases the size of the left ventricle, causing the snap sound associated with MVP to happen earlier

Inspiration does not have an effect on cardiac sounds associated with the mitral valve but will change the timing of pulmonary valve sounds as well as S2

Question 17

A patient presents with shortness of breath, a feeling their heart is skipping a beat,
and sweating. After ruling out a myocardial infarction, an echocardiogram reveals
significant bulging of the mitral leaflets into the left atrium, along with a small
backflow of blood from the left ventricle into the left atrium. The heart is found to
be pumping an adequate amount of blood into systemic circulation. What is the best
treatment for this patient?

A. ACE inhibitor

B. Calcium channel blocker

C. Diuretic

D. Reassurance

E. Surgery

Answer 17

D. Reassurance

patient has MVP with a small amount of mitral regurgitation, so the patient should be reassured that these findings are benign