The mitral valve is the inflow valve into the left side of the heart. It closes during systole (when the ventricle contracts or squeezes blood out into Mitral valve repair is an open heart procedure performed by cardiothoracic surgeons to treat stenosis (narrowing) or regurgitation (leakage) of the mitral valve. The mitral valve is the "inflow valve" for the left side of the heart. Blood flows from the lungs, where it picks up oxygen, and into the left atrium. When it opens, the mitral valve allows blood to flow from the left atrium to the heart's main pumping chamber called the left ventricle. It then closes to keep blood from leaking back into the lungs when the ventricle contracts (squeezes) to push blood out to the body. It has two flaps, or leaflets.

Occasionally, the mitral valve is abnormal from birth (congenital). More often the mitral valve becomes abnormal with age (degenerative) or as a result of rheumatic fever. In rare instances the mitral valve can be destroyed by infection or a bacterial endocarditis. Mitral regurgitation may also occur as a result of ischemic heart disease (coronary artery disease). When it opens (left), the mitral valve allows blood to flow into the heart's main pumping chamber called the left ventricle. It then closes (right) to keep blood from leaking back into the lungs when the ventricle contracts (squeezes) to push blood out to the body. It has two flaps, or leaflets.

Often the mitral valve is so damaged that it must be replaced (refer to Mitral Valve Replacement). Occasionally, however, the valve can be repaired rather than replaced. One type of repair is a procedure called mitral commisurotomy. Mitral commisurotomy can be performed for some valves that are narrow or "stenotic" either from birth or from damage by rheumatic fever. Most often today, rheumatic mitral stenosis is treated by balloon valvuloplasty, a procedure performed in the cardiac catheterization laboratory by interventional cardiologists. Using a catheter with a balloon on the end, the balloon is expanded inside the valve "stretching" it open.

More often mitral valve repair is performed to correct a leaking or regurgitant valve. Congenital mitral regurgitation may be due to a cleft mitral valve (a valve with a separation or cleft down the middle) associated with an atrial septal defect, a type of hole in the heart between the low pressure chambers or atria. Such valves can sometimes be repaired simply by closing the cleft with sutures. Valves regurgitant due to bacterial endocarditis can occasionally be repaired, however the majority of mitral valve repairs are performed for degenerative disease. Degenerative mitral valve disease may be due to an elongation or rupture of the chordal apparatus, the "heart-strings" that support the valve normally, or due to a more generalized weakness of the valve itself such as the "floppy valve" syndrome in which all of the components of the valve are enlarged and elongated.

The aorta and the rest of the body). When the mitral valve leaks, blood flows backwards into the lungs. The ventricle must therefore pump more blood with each contraction to produce the same forward output of blood throughout the body. This resulting condition is called a volume overload. The heart can compensate for this volume overload for many months or years (provided the leakage came on slowly and progressively), but it eventually begins to fail producing symptoms of shortness of breath or fatigue.

The indications for mitral valve repair are undergoing constant re-evaluation. Recent evidence suggests that earlier surgical intervention, particularly if repair is possible, may prevent irreversible damage to the heart. The decision regarding when to proceed with surgery should be made with your doctor. This decision will require judgment regarding the risk of surgery and the benefits available from surgery. In some cases blood pressure medications, such as ACE-inhibitors can significantly relieve symptoms.

Severe mitral regurgitation in the presence of symptoms of congestive heart failure is usually an indication for surgery. Severe regurgitation diagnosed by echocardiography, even without symptoms, may be sufficient to warrant repair. Enlargement of the left atrium, particularly in the setting of the recent onset of an irregular heartbeat (atrial fibrillation, premature atrial contractions, paroxysmal atrial tachycardia, etc.) is considered by many doctors also to be an indication for surgery.