The mitral valve controls blood flow between your heart’s left atrium and left ventricle. When it works well, blood moves forward smoothly with every heartbeat. But when the valve becomes too narrow (stenosis) or too leaky (regurgitation), the heart has to work much harder to keep blood moving. Over time, this extra strain can enlarge the heart, reduce its pumping ability, and cause symptoms ranging from mild fatigue to severe shortness of breath. Mitral valve disease can develop from age-related changes, past infections, congenital conditions, or other structural problems.
Overview
Mitral valve disease refers to any condition that prevents the mitral valve from opening or closing properly. The two most common forms are mitral regurgitation, where blood leaks backward into the left atrium, and mitral stenosis, where the valve becomes narrowed and restricts forward flow. Some people have a combination of both.
In a healthy heart, the mitral valve opens widely as the left ventricle fills and closes tightly when the ventricle contracts. When the valve becomes damaged, thickened, stretched, or calcified, it fails to seal properly or becomes too narrow. As the condition progresses, the left atrium and left ventricle begin to enlarge, pressure builds in the lungs, and symptoms gradually appear.
Mitral valve disease can remain silent for years, even decades, or it can cause rapid changes depending on the underlying cause. Early detection and ongoing follow-up are the keys to preventing long-term complications such as atrial fibrillation, pulmonary hypertension, and heart failure.
Causes
Mitral valve disease develops from several different underlying problems, each affecting the structure or function of the valve in its own way.
- Degenerative changes commonly occur with aging. Over time, the valve tissue weakens, becomes redundant, or develops calcium deposits that prevent proper closure. This is the most frequent cause of mitral regurgitation in older adults.
- Mitral valve prolapse is another frequent cause. The valve leaflets become too flexible and bulge backward into the left atrium, which can lead to leakage. Many people with prolapse never develop symptoms, but some eventually progress to significant regurgitation.
- Rheumatic fever, although much less common today, can permanently scar and thicken the valve, leading to mitral stenosis or a mixture of stenosis and regurgitation. In parts of the world where rheumatic disease remains prevalent, it is a leading cause.
- Infective endocarditis is a serious infection of the valve that destroys tissue, causing acute and severe regurgitation that often requires urgent surgical repair.
- Congenital abnormalities present at birth, such as abnormally formed leaflets or chordae, may cause mitral valve dysfunction early in life or gradually worsen with age.
- Functional mitral regurgitation occurs when the valve itself is normal but the left ventricle becomes enlarged and cannot support proper closure of the leaflets. This is commonly seen in people with long-standing heart failure or dilated cardiomyopathy.
Symptoms
Symptoms depend on how severe the valve problem is and how quickly it develops. Many people with mild mitral valve disease feel completely normal for years.
As the condition progresses, the most common symptoms include shortness of breath, particularly during exertion or when lying flat. Fatigue or reduced exercise capacity also develops as the heart’s pumping efficiency declines. Some people notice palpitations or irregular heartbeats due to atrial fibrillation, which is common in mitral valve disease.
Swelling in the legs or ankles can occur when pressure builds in the lungs and right side of the heart. A chronic cough, especially at night, or waking up short of breath can signal fluid buildup in the lungs. In sudden, severe regurgitation—such as from infective endocarditis—symptoms appear rapidly, with severe shortness of breath and low blood pressure.
Diagnosis
Diagnosis begins with a careful history and physical exam. A characteristic heart murmur often provides the first clue. To confirm the diagnosis and determine severity, an echocardiogram is essential. This ultrasound test shows how the valve moves, how much blood is leaking or how narrow the opening has become, and how the heart chambers are responding.
An electrocardiogram may reveal atrial fibrillation or signs of chamber enlargement. A chest X-ray can show enlargement of the heart or fluid in the lungs. For complex cases or surgical planning, transesophageal echocardiography or cardiac MRI may provide more detailed information. Stress testing can also help assess how symptoms correlate with exercise.
Regular follow-up is crucial. Even if symptoms are mild, mitral valve disease can progress unpredictably, and periodic imaging allows timely intervention before irreversible heart damage occurs.
Treatment
Treatment depends on the type and severity of the valve problem, your symptoms, and how your heart is adapting.
Medications do not fix the valve but help control symptoms and reduce stress on the heart. Diuretics relieve congestion, blood pressure medications reduce the workload on the heart, and medications to control heart rhythm or prevent blood clots are used when atrial fibrillation is present.
For significant mitral regurgitation or stenosis, procedures to repair or replace the valve may be recommended. Mitral valve repair is preferred whenever possible because it preserves the native valve and offers excellent long-term outcomes. Techniques include surgical repair or less invasive catheter-based options such as transcatheter edge-to-edge repair (like MitraClip).
When the valve is too damaged for repair, replacement with a mechanical or bioprosthetic valve may be necessary. Decisions depend on age, anatomy, surgical risk, and lifestyle considerations.
In rheumatic mitral stenosis, balloon valvuloplasty can widen the valve without major surgery if the anatomy is suitable.
What Happens If Left Untreated
Untreated mitral valve disease gradually strains the heart and lungs. Over time, the left atrium enlarges and pressure in the lungs rises, leading to pulmonary hypertension. This makes breathing difficult and increases the workload on the right side of the heart, eventually causing right-sided heart failure.
Atrial fibrillation commonly develops as the left atrium enlarges. This irregular rhythm increases the risk of stroke and often worsens symptoms.
In advanced disease, the left ventricle weakens and heart failure develops. Fatigue, swelling, shortness of breath, and reduced quality of life follow. Acute severe regurgitation, such as from valve infection, can rapidly become life-threatening without urgent treatment.
What to Watch For
Shortness of breath during activity or when lying flat, new or worsening fatigue, swelling in the legs, or palpitations should prompt medical evaluation. A sudden increase in symptoms, rapid weight gain from fluid retention, or the onset of atrial fibrillation requires prompt attention. Even subtle changes matter because early interventions lead to far better outcomes.
Living with Mitral Valve Disease
Most people with mitral valve disease live full and active lives, especially with consistent follow-up and appropriate treatment. Regular echocardiograms help monitor progression. Managing blood pressure, maintaining a healthy weight, limiting salt, staying active, and avoiding smoking all support heart health.
If you have atrial fibrillation, taking medications to control heart rhythm or prevent strokes is essential. After valve repair or replacement, activity levels often improve dramatically, though long-term follow-up with a cardiologist remains crucial.
Listening to your body, reporting symptom changes early, and attending scheduled evaluations help ensure the best possible outcomes. Many people return to normal routines, exercise comfortably, and maintain excellent quality of life with the right care.
Key Points
Mitral valve disease affects the valve between the left atrium and left ventricle, leading to narrowing, leakage, or both. It may remain silent for years or gradually produce symptoms like shortness of breath, fatigue, or palpitations.
Diagnosis relies primarily on echocardiography, supported by physical exam and EKG findings. Treatment ranges from symptom-relieving medications to valve repair or replacement, depending on severity.
Untreated disease can lead to atrial fibrillation, pulmonary hypertension, and heart failure. Early detection and timely intervention significantly improve long-term outcomes.
With proper follow-up, lifestyle care, and modern treatment options, most people with mitral valve disease can live a long, active, and healthy life.
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Reference: Mitral Valve Disease
