The mitral valve controls blood flow between the left atrium and the left ventricle. The left atrium is the chamber where the blood returns from the lungs after being oxygenated. It is then pumped through the mitral valve to the left ventricle, which pumps blood to the body’s organs and tissues. The mitral valve has two flaps called leaflets. These leaflets are supported by thin cords similar to those that support parachutes, and prevent the valve from bulging in the opposite direction when the ventricle contracts. When the atrium contracts, the mitral valve opens to allow blood to flow to the ventricle. When the ventricle contracts, the mitral valve closes to prevent blood from flowing backwards into the atrium. When the mitral valve leaks do to not closing properly it is called mitral regurgitation.  A mild amount of mitral regurgitation is usually tolerable within normal physiological limits.  When the mitral regurgitation becomes moderate to severe is when concern is raised. Mitral regurgitation is a condition where the valve between the heart’s two left chambers doesn’t close all the way, and allows some blood to flow backward. If it becomes significant, mitral regurgitation causes the heart to work harder and can lead to heart failure.