Mitral Valve Disease
Mitral valve disease refers to any condition affecting the mitral valve, which sits between the left atrium and the left ventricle. The valve can either fail to close properly (mitral regurgitation), causing blood to leak backward, or fail to open fully (mitral stenosis), restricting blood flow into the left ventricle. Mitral valve prolapse is also a common related condition. Causes range from degenerative valve changes and prior heart attack to rheumatic heart disease and infections. Echocardiography is the central diagnostic tool, with cardiac MRI and CT, and transesophageal echocardiography adding important information.
What is it?
The mitral valve sits between the left atrium (which receives oxygen-rich blood from the lungs) and the left ventricle (the heart’s main pumping chamber). It has two leaflets that open during ventricular filling to let blood flow forward and close during ventricular contraction to prevent backflow. The valve is supported by a fibrous ring (the annulus) and by small cords (chordae tendineae) attached to muscles inside the ventricle (papillary muscles). Mitral valve disease describes any condition that affects this structure or its function.
Mitral regurgitation (MR)—a leak in which blood flows backward from the left ventricle into the left atrium during contraction—is the most common form. MR can be primary (caused by a problem of the valve itself, such as degenerative disease, mitral valve prolapse, infection, or rheumatic disease) or secondary (caused by enlargement of the left ventricle or its supporting structures, often from heart failure, prior heart attack, or atrial fibrillation). Severity ranges from mild to severe and is graded using a combination of imaging measurements.
Mitral stenosis is a narrowing of the valve that restricts blood flow from the atrium into the ventricle. The most common cause worldwide is rheumatic heart disease, an immune response after streptococcal infection that gradually scars the valve. Less commonly, severe calcification of the mitral annulus (mitral annular calcification) can produce calcific mitral stenosis, particularly in older adults. Congenital mitral stenosis is rare.
Mitral valve prolapse (MVP) is a condition in which one or both leaflets bulge backward into the left atrium during ventricular contraction. It is one of the most common valve conditions and is often discovered incidentally. Most patients with MVP have no significant problems, but a subset develop progressive mitral regurgitation requiring treatment, and a smaller subset have higher-risk features associated with arrhythmias.
Other less common conditions affecting the mitral valve include infective endocarditis (an infection of the valve), traumatic injury, and congenital abnormalities.
Symptoms depend on the type and severity of disease. Many people with mild mitral valve disease have no symptoms and may only have a heart murmur identified on physical examination. As disease progresses, symptoms may include shortness of breath (especially with exertion or when lying flat), fatigue, reduced exercise tolerance, palpitations (particularly with atrial fibrillation), chest discomfort, lightheadedness, leg swelling, or signs of heart failure. Significant mitral stenosis can also be associated with coughing up blood and an increased risk of clot formation in the left atrium. Sudden, severe symptoms—such as acute shortness of breath after a heart attack or chest trauma—may indicate acute mitral regurgitation, a medical emergency.
Evaluation begins with a careful history and physical examination, including listening for heart murmurs. ECG provides information about heart rhythm (atrial fibrillation is common in mitral disease) and chamber strain. Transthoracic echocardiography is the central imaging test for evaluating the mitral valve and provides detailed information about leaflet structure, motion, regurgitation, valve area, gradients, and overall heart function. Transesophageal echocardiography offers higher-resolution images of the mitral valve and is particularly useful for detailed assessment, evaluation for endocarditis, and procedural planning. Cardiac MRI adds detailed information about chamber sizes, function, regurgitant volumes, and tissue characteristics. Cardiac CT is increasingly important for planning transcatheter mitral interventions. Exercise testing may help clarify symptom significance. Cardiac catheterization may be used to assess pressures, coronary anatomy, and severity in selected cases.
Important to Know
Management of mitral valve disease is highly individualized and depends on the specific condition, the severity of disease, the patient’s symptoms, the impact on heart function, and overall health. Many patients with mild or moderate disease can be managed with periodic monitoring and treatment of associated conditions. Significant or symptomatic disease often requires definitive treatment with valve repair or replacement.
For mild and moderate mitral regurgitation, ongoing monitoring with echocardiography is typical, with frequency tailored to severity. Treatment focuses on managing associated conditions, particularly blood pressure, heart failure, and atrial fibrillation. Anticoagulation may be needed in patients with atrial fibrillation, prior clots, or mechanical prosthetic valves. For secondary mitral regurgitation related to heart failure, optimized guideline-directed medical therapy is often the first line of management.
Severe mitral regurgitation that becomes symptomatic—or develops other high-risk features such as significant ventricular enlargement or reduced pumping function—generally requires definitive treatment. Surgical mitral valve repair is often preferred when feasible, particularly for primary regurgitation due to degenerative disease, because preserving the native valve has long-term benefits. When repair is not possible, surgical valve replacement is performed. Transcatheter mitral valve interventions—including edge-to-edge clip repair and, increasingly, transcatheter replacement—are options for selected higher-risk patients.
Significant mitral stenosis may be treated with percutaneous balloon mitral valvuloplasty (a catheter-based procedure that opens the valve) when the anatomy is suitable, or with surgical commissurotomy or valve replacement when balloon valvuloplasty is not appropriate.
Mitral valve prolapse without significant regurgitation usually requires only reassurance and periodic monitoring. Patients with significant prolapse-related regurgitation may eventually need repair. A small subset of patients with prolapse may have arrhythmia risk that warrants additional evaluation, including ambulatory monitoring and, when appropriate, electrophysiology consultation.
Endocarditis affecting the mitral valve is a serious infection often requiring prolonged intravenous antibiotics and, in many cases, surgical treatment. Prevention with appropriate dental and procedural antibiotics may be recommended in selected high-risk patients.
Care is typically coordinated by primary care clinicians, cardiologists, and—when intervention is needed—cardiothoracic surgeons, interventional or structural cardiologists, and dedicated heart valve teams. Imaging findings are interpreted alongside symptoms, examination, and other test results.
Lifestyle measures support overall cardiovascular health and may help slow progression in some forms: not smoking, healthy diet, regular physical activity (individualized when significant disease is present), weight management, treatment of sleep apnea, limited alcohol, and good control of blood pressure, cholesterol, and diabetes.
Red flag symptoms include severe or worsening shortness of breath, severe chest pain, fainting, severe palpitations or rapid heart rate with lightheadedness, severe leg swelling, sudden weight gain, persistent fever (which may suggest endocarditis), coughing up blood, or signs of stroke or shock. These warrant prompt or urgent medical evaluation.