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For further information, see CMDT Part 10-12: Mitral Regurgitation
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Mitral regurgitation results from
Displacement of papillary muscles (dilated cardiomyopathy)
Excessive length of chordae or myxomatous degeneration of leaflets (mitral prolapse)
Noncontraction of annulus (annular calcification)
Scarring (rheumatic fever, calcific invasion)
Infection (endocarditis)
Mitral regurgitation places a volume load on heart (increased preload) and reduces afterload, resulting in enlarged left ventricle (LV) and initial increase in ejection fraction (EF)
Over time, myocardial contractile function is reduced and EF drops
The Carpentier classification is used by some experts to categorize the mobility of the mitral leaflets:
Type 1 is normal
Type II indicates increased leaflet motion (as in prolapse or chordal rupture)
Type IIa indicates restricted mitral leaflets in both systole and diastole
Type III indicates papillary muscle displacement
Type IIIb indicates restricted motion in systole only
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Pansystolic murmur at the apex, radiating into the axilla in most patients; murmur does not change in intensity after a premature beat, since the LV to left atrial (LA) gradient is unaffected
Often associated with an S3
Hyperdynamic LV impulse
Brisk carotid upstroke
May be asymptomatic for many years (or life)
When regurgitation develops acutely, left atrial pressure rises abruptly, leading to pulmonary edema if severe
When regurgitation progresses more slowly, exertional dyspnea and fatigue worsen gradually over many years
Chronic LA and LV enlargement may result in subsequent atrial fibrillation and LV dysfunction
Systemic embolization occurs but is relatively unusual compared with other conditions causing atrial fibrillation
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ECG: LA abnormality or atrial fibrillation and LV hypertrophy
Chest radiograph: LA and LV enlargement
Doppler transthoracic echocardiography (TTE)
Confirms the diagnosis, etiology and estimates severity by a variety of methods
Used for measuring LV function and LV end-systolic and diastolic sizes
Should be done at least yearly in patients with severe mitral regurgitation (stage C1) but preserved LV dimensions
Transesophageal echocardiography (TEE)
Coronary angiography is often indicated to determine the presence of coronary artery disease before valve surgery in all men over age 40 years and menopausal women with risk factors
Exercise hemodynamics with either Doppler TTE or cardiac catheterization may be useful when the symptoms do not fit the anatomic severity of mitral regurgitation
B-type natriuretic peptide (BNP or pro-NT-BNP) is useful in the early identification of LV dysfunction in the presence of mitral regurgitation
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Chronic regurgitation usually requires surgery when symptoms develop or in asymptomatic patients when the LV end-systolic dimension (LVESD) is > 4.0 cm or EF < 60%
The 2017 update of the valvular guidelines has added a IIa indication for mitral valve surgery when the LVEF is > 60% and the LVESD is still < 4.0 cm