Conditions affecting the cusps:
- Congenital cleft mitral valve
- Rheumatic fever
- Surgical trauma
- Infective endocarditis
- Myxomatous degeneration
Conditions affecting the Codae tindinae
- Mitral valve prolapse
- Marfan's syndrome.
- Rupture
Conditions affecting the papillary muscle
- papillary muscle ischemia
- papillary muscle atrophy
- papillary muscle infiltration
Conditions affecting the mitral ring:
- disease such as dilated cardiomyopathy and mitral annulus calcification which cause left ventricular dilatation with subsequent ring dilatation.

Hemodynamics

Regurgitation of the blood to the left atrium during systole leads to a subsequent decrease in left ventricular stroke volume and increased left atrial pressure.

This leads to pulmonary congestion and later pulmonary arterial hypertension.

During diastole the blood flow across the mitral valve is increased leading to left ventricular hypertrophy and later on left ventricular failure.

Treatment

Acute mitral regurge: is treated pre-operatively as acute pulmonary edema in addition to a peripheral vasodilator to be followed by urgent surgery (catheterization and valve replacement) in severe cases.

Chronic mitral regurge:

If mild & well tolerated then give prophylaxis against rheumatic fever and infective endocarditis.
Moderate regurge or symptomatic cases: Digoxin, vasodilators and diuretics. Anticoagulation if co-existing atrial fibrillation.
Progressive disease: Surgery which consists of repair or replacement.