Mitral stenosis is abnormal narrowing or blocking of the mitral valve. The mitral valve lies between the left atrium (one of the upper chambers in the heart) and left ventricle (one of the lower chambers in the heart). A narrow valve means that the left atrium must pump harder to move blood into the left ventricle. If the left atrium cannot empty the blood properly, blood backs up into the right-sided heart system, and fluid leaks into the lungs. Mitral stenosis occurs two to four times more often in women than in men. It is a major cause of congestive heart failure.
The cause may be scarring of the valve from rheumatic fever that occurred earlier in life, usually in childhood. Rheumatic fever comes from a bacterial (streptococcus, or strep) infection. Other causes are congenital heart disease, calcium deposits, and infection.
Symptoms include difficulty breathing (especially when lying down), swelling (edema) in legs, and tiredness. Other symptoms may be irregular heartbeat, coughing up blood, and chest pain. If an abnormal heartbeat called atrial fibrillation develops, the atrium doesn’t contract normally, so blood pools in the atrium. Clots may form and move out of the heart to the brain and cause a stroke.
The health care provider can make a diagnosis by listening to heart sounds. Blood moves abnormally through the mitral valve and causes a sound called a murmur. The health care provider hears the murmur with a stethoscope. The timing and location of the murmur help the health care provider tell which valve is affected. A sonogram of the heart (echocardiogram) can confirm the diagnosis. Other tests ordered may include a chest x-ray and electrocardiography (ECG).
For a mild condition, attempts are made to prevent complications with medicines. When medicines cannot control symptoms any longer, an operation to have the mitral valve widened or replaced is usually performed. Percutaneous balloon mitral valvotomy (BMV) is a non-surgical procedure using catheters inserted from vessels in the groin and guided into the chambers of the heart. The catheter has a balloon tip that is inflated and deflated several times to widen the valve opening. If BMV cannot be performed, surgery to replace the valve may be necessary.
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