What is the significance mitral insufficiency?

Mitral insuffiency: Mitral insufficiency is leakage of the mitral valve. This valve between the left atrium and left ventricle assures that when the ventricle (the main pumping chamber) contracts, all the blood moves forward through the aortic valve into the aorta. When leaking, blood flows backwards. This can be a little or a lot, making the heart less efficient and causing symptoms such as shortness of breath...

Mitral valve: The mitral valve has to open properly to let blood flow into the left ventricle from the atrium. If it doesn't, we call this stenosis. It has to close to keep the blood flowing toward the body, if it doesn't we call this regurgitation or insufficiency. Either or both problems can exist with the valve if its abnormal. Insufficiency is more common.