Mitral Prolapse and Regurgitation
- causes and risk factors
- signs and symptoms
- diagnosis
- pathophysiology
- treatments
- consequences and course
- patient education
- community resources
- references
Causes and Risk Factors
Mitral valve prolapse is one of the most common valvular abnormalities in the industrialized world. It is estimated to affect 3% or more of adults, most often young women.
Causes of mitral regurgitation include:
- myxomatous (45%)
- postinflammatory scarring following rheumatic fever (40%)
- ischemic (10%) - LCX, RCA blockages can lead to papillary muscle ischemia
- endocarditis (3%)
Other causes include mitral leaflet disorders, rupture of chordae or papillary muscles, mitral annulus disorders, or primary mitral valve prosthetic disorders.
Signs and Symptoms
Mitral prolapse is usually detected incidentally, but can cause serious complications in a asmall minority.
dyspnea, orthopnea, PND
fatigue
pulmonary hypertension, right sided failure
hemoptysis
systemic embolization due to atrial fibrillation, 2e to dilation
Can lead to S3 if advanced +/- thrill
diastolic flow rumble if severe
Mitral prolapse presents as a midsystolic click. If regurgitation occurs, a late systolic or pansystolic murmur, loudest at apex, with potential radiation to axilla, can be heard.
Some people experience angina, dyspnea, and fatigue, as well as mental health concerns such as depression, anxiety, and personality disorders.
Examine under different loading conditions
chronic
pulse: brisk, low volume
apex: hyperdynamic, laterally displaced (key)
S1 soft or normal
S2 wide split due to early A2
acute
LV normal size but hyperdynamic
S1 load
systolic murmur, which may or may not be pan-systolic
inflow rumble
S3 can be present and may be the only abnormality
Diagnosis
Mitral valve prolapse is defined by echoradiography.
ECG:
- LA enlargement
- A fib
- LVH in 50% of people with severe MR
- RVH in 15%
- combined hypertrophy
CXR:
- increased LV
- much enlarged LA
Can be acute or chronic.
ECHO is best.
Pathophysiology
Myxomatous degeneration can lead to ballooning of the mitral leaflets, which can become thick and rubbery. Tendinous cords can become elongated, thinned, and occasionally ruptured.
Myxomatous degeneration is common in Marfan syndrome, caused by mutations in fibrillin-1.
Acute mitral regurgitation leads to pulmonary edema due to backflow through high LA pressure. Chronic mitral regurgitation leads to dilated LA, with normal pressure. Thus pulmonary edema decreases.
Treatments
Mechanical problems can only be fixed surgically, with valvular repair or replacement.
Repair is better than replacement, if possible, as it is in 70-90% patients
- lower operative mortality (2-3% vs 2-7%)
- better outcome
- no anticoagulation needed
- LVEF preserved
Timing is difficult - don't rush into open heart surgery, but delays too long can reduce survival.
Indications include NYHA class III or IV
- EF <60% or above 60% but steadily dropping
- LVESD >45mm
minor criteria:
- any symptoms of heart failure
- flail mitral leaflet
- left atrial diameter above 45 mm
- atrial fibrillation
LV ejection fraction is the strongest predictor of outcome following surgery and should be assessed quantitatively suing MUGA or echo.
If EF <30%, medical management is best for now. Repair may be useful.
subacute bacterial endocarditis prophylaxis is not indicated and not normally done.
Course
Mitral valve prolapse almost always has no ill effects, but in 3% of people, seriosu complications can arise:
- infective endocarditis
- mitral regurgitation
- stroke or other systemic infarct
- arrhythmias, with occasional sudden death
Mitral regurgitation can cause serious, life-threatening problems.
Patient Education
Community Resources