Acute severe mitral regurgitation is a life-threatening disorder. The causes are listed below:

1. Papillary muscle rupture after acute myocardial infarction: This usually occurs as a complication on an inferior MI (right coronary artery supply) since the posteromedial papillary muscle receives its sole blood supply from this vessel. The anterolateral papillary muscle has dual blood supply from the left anterior descending and circumflex coronary arteries.

2. Mitral valve endocarditis: Most commonly related to Staph aureus, but other organisms can cause valve destruction as well.

3. Spontaneous chordal rupture: This is more common in mitral valve prolapse (most often posterior leaflet) and rheumatic mitral valve disease (most often anterior leaflet).

4. Trauma.

5. Complication from percutaneous mitral balloon valvuloplasty.