Mitral insufficiency (MI),
mitral regurgitation 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. MI is the most common form of
valvular heart disease.