<unk>  is a disorder in which the heart's mitral valve suddenly does not close properly, causing blood to flow backward (leak) into the upper heart chamber when the left lower heart chamber contracts.  Acute<unk>  can develop into chronic<unk> , a long-term disorder.
Mitral regurgitation
Aortic regurgitation
Tricuspid regurgitation
Mitral stenosis
Functional mitral regurgitation
Pulmonic regurgitation
Mitral valve prolapse
Aortic stenosis