Mitral valve regurgitation — or mitral regurgitation — is when your heart's mitral valve doesn't close tightly, allowing blood to flow backward in your heart. As a result, blood can't move through your heart or to the rest of your body as efficiently, making you feel tired or out of breath.
Treatment of mitral valve regurgitation — also called mitral insufficiency or mitral incompetence — depends on how severe your condition is, whether it's getting worse and whether you have symptoms. For mild cases, treatment may not be necessary.
You may need heart surgery to repair or replace the valve for severe cases. Left untreated, severe mitral valve regurgitation can cause heart failure or heart rhythm problems (arrhythmias).