Can someone explain to me about mitral heart valvedisease?

Valve. The mitral valve separates the top and bottom chambers on the left side of the heart. The diseases valve can leak or become narrow. Both can eventually lead to heart failure and require closer monitoring by a cardiologist.
Leak and/or blockage. The mitral valve separates the left receiving chamber (atrium) from the left main pumping chamber (ventricle). When the lv squeezes the valve closes preventing blood from going backwards. The valve can leak (regurge) or be blocked (stenosis). This can be followed with echo & treated with meds. When severe enough you may need surgery. Repair for most leaks and replacement for most stenosis.
2 major problems. Stenosis or regurgitation. Regurgitation may occur from primary valve problems or from left ventricular problems. Many mitral valve regurgitation cases best treated when no heart failure symptoms with very good long term outcomes. Many mitral valve anatomic problems can be repaired. Replacement used for when repair not feasible or for failed repair. Did this help?
Agree. Leak (regurgitation) is the most common. Prolapse/myxomatus disease is the most common cause. Narrowing (stenosis) is most commonly caused by rheumatic heart disease, not as prevalent as regurgitation ( in the us).