The major causes of mitral regurgitation are flail mitral valve, mitral valve prolapse, endocarditis, ischemic heart disease with papillary muscle displacement, functional mitral regurgitation from cardiomyopathy, and rheumatic heart disease.
Echocardiography is the preferred examination to determine mitral regurgitation. It clearly shows the extent of left atrial and left ventricular enlargement and also the presence and severity of mitral regurgitation. Transesophageal echocardiography with Doppler or 2D echocardiography and color flow Doppler imaging allows detailed assessment of the mitral valve.
Structural abnormalities found in mitral regurgitation include left atrial and left ventricular size and appearance of the mitral apparatus.
- Mild mitral regurgitation: normal or near-normal left atrial size, left ventricular size, and intact mitral apparatus.
- Moderate mitral regurgitation: some degree of enlargement of the left atrium, different degrees of mitral apparatus abnormalities, and normal or mildly dilated left ventricle.
- Severe chronic mitral regurgitation: some degree of left ventricular dilatation, moderate to severe left atrial enlargement, and ruptured papillary muscle, flail mitral leaflet, or malcoaptation of the mitral leaflets.