Mitral insufficiency Mitral insufficiency Mitral regurgitation (MR), Mitral insufficiency (abbreviation MI best avoided because it is more commonly used in lieu of myocardial infarction), or mitral incompetence is a disorder of the heart in which the mitral valve does not close properly when the heart pumps out blood. It is the abnormal leaking of blood backwards from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts, i.e. there is regurgitation of blood back into the left atrium. MR is the most common form of valvular heart disease. The symptoms associated with MR are dependent on
Mitral insufficiency MR and mitral valve prolapse are also common in Ehlers–Danlos syndromes. Secondary mitral insufficiency is due to the dilatation of the left ventricle that causes stretching of the mitral valve annulus and displacement of the papillary muscles. This dilatation of the left ventricle can be due to any cause of dilated cardiomyopathy including aortic insufficiency, nonischemic dilated cardiomyopathy, and Noncompaction cardiomyopathy. Because the papillary muscles, chordae, and valve leaflets are usually normal in such conditions, it is also called functional mitral insufficiency. Acute MR is most often caused by endocarditis, mainly "S. aureus". Rupture or dysfunction of the papillary muscle