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 valve about 20% to the volume in the left ventricle prior to ventricular systole, and is known as the "atrial kick". The mitral annulus changes in shape and size during the cardiac cycle. It is smaller at the end of atrial systole due to the contraction of the left atrium around it, like a sphincter. This reduction in annulus size at the end of atrial systole may be important for the proper coapting of the leaflets of the mitral valve when the left ventricle contracts and pumps blood. Leaking valves can be corrected by mitral valve annuloplasty, a common surgical procedure