Does Rheumatic Heart Disease Cause Mitral Stenosis?

Mitral stenosis is a type of valvular heart disease characterized by narrowing of the mitral valve. The mitral valve, which is made up of two tissue flaps called leaflets, is located between the left atrium and left ventricle of the heart. It opens as blood flows from the left atrium and left ventricle and instantly shuts to prevent blood from flowing backward. 

A faulty valve does not open or close completely. Therefore, less blood circulates in the body. This causes a pressure buildup, which causes enlargement of the upper heart chamber and can lead to pulmonary edema (fluid accumulation in the lungs). This, in turn, causes breathing problems.

Untreated rheumatic heart disease scars the mitral valve and causes mitral stenosis, leading to various cardiac complications. Mitral stenosis is classified into three types based on the severity: mild, moderate, and severe.

Mitral stenosis occurs more frequently in women and most commonly affects people aged 30 to 50 years. Other factors that may increase the risk of mitral stenosis besides untreated rheumatic fever include:

• Congenital defects in the valve
• Family history of valve defects
• Other chronic illnesses:
  • Hypertension
  • Chronic renal disease
  • Coronary artery disease 
• Aging: Calcium accumulation around the mitral valve is more common in older people.
• Radiation treatment: Radiation alters the shape and structure of the mitral valve. People who get radiation therapy to the chest for some forms of cancer may develop mitral valve stenosis in rare cases.
• Use of illegal drugs: 3,4-methylenedioxymethamphetamine, sometimes known as molly or ecstasy, increases the risk of mitral valve disease.
• Certain medications: Ergot alkaloids and ergotamine can induce heart valve scarring, which leads to mitral stenosis in rare cases. Older weight-loss medications including Pondimin (fenfluramine) or Redux (dexfenfluramine) have also been associated with heart valve dysfunction and other cardiac issues. 

Not everyone with mitral valve stenosis experiences symptoms. For decades, some people may feel fine or have very minor symptoms. However, even mild disorders can rapidly worsen. Symptoms may appear or intensify with an increase in heart rate during exercise, or they can be prompted by pregnancy, stress, or illnesses.

Mitral stenosis may lead to various symptoms, including:

• Breathing difficulties, particularly during activity and when lying down
• Shortness of breath while sleeping, which causes nighttime wakening
• Fast or irregular heartbeat
• Chest pain, characterized by squeezing, pressure, or tightness
• Exertion leading to cough
• Fatigue
• Swelling due to edema (fluid accumulation) in the legs or feet 
• Blood in sputum
• Persistent respiratory infections 
• Fainting
• Lightheadedness

Untreated mitral stenosis can result in various complications, including:

• Arrhythmias: Mitral valve stenosis can result in atrial fibrillation (AFib), which is an irregular heartbeat. The risk increases with age and the severity of stenosis.
• Blood clot formation: Irregular heartbeats caused by mitral valve stenosis can lead to the formation of blood clots in the heart.  A stroke can occur if a blood clot from the heart travels to the brain.
• Pulmonary hypertension: High blood pressure in the arteries of the lungs can occur when a constricted mitral valve slows down or stops blood flow. Reduced blood flow increases the pressure in the pulmonary arteries. Therefore, to pump blood through the lungs, the heart must work harder.
• Right-sided heart failure: Blood flow changes and high pressure in the pulmonary arteries can put a load on the heart. To pump blood to the right-sided heart chambers, the heart must work harder. The additional effort eventually leads the heart muscle to weaken and fail.

Mitral valve stenosis is often diagnosed using a combination of tests. 

During a typical physical examination, doctors detect a heart murmur first with a stethoscope. The volume of the murmur, its location in the chest, and the types of sounds it produces (such as gurgling or blowing) will all help the doctor diagnose the condition.

Tests that may be ordered include:

• Electrocardiogram: Records the electrical activity of the heart and detects heart murmurs.
• Echocardiography: An echocardiography is a definitive test for confirming mitral valve stenosis. It is a specialized treatment that obtains images of the heart and its components using ultrasonic sound waves. Echocardiograms are noninvasive and take around an hour to complete.
• Chest X-ray: Chest X-rays produce images of the structures inside the chest, including the heart, lungs, and chest wall, using a low dose of radiation.
• Cardiac catheterization: This is a technique used to detect abnormalities in the coronary arteries. A catheter (long, thin tube) is threaded into the heart from an artery or vein in the groin, arm, or neck. A contrast solution is injected into the artery, and X-rays are used to look for blockages and other abnormalities.
• Transesophageal echocardiography: This is a test that produces a picture of heart structures by passing a tiny transducer (such as a microphone) down the throat.

Medication cannot cure a valve issue, but it can alleviate symptoms. If necessary, your healthcare provider may give diuretics to minimize fluid accumulation in the lungs, blood thinners to prevent clot formation, or medications to manage heart rhythm. 

The mitral valve is typically repairable or replaceable by surgery or less invasive methods. Criteria that can influence surgery selection are as follows:

• Origin of the mitral stenosis (rheumatic or calcific)
• State of the valve
• Risk of surgery
• The intensity of symptoms and cardiac function
• Availability of treatments

A commissurotomy may be performed to treat rheumatic mitral stenosis. The valve leaflets that have been fused are separated during this treatment. This can be done using a balloon (percutaneous mitral balloon commissurotomy) or surgery. Once the leaflets are split, the valve opening and blood flow through it are enhanced. More extensive rheumatic mitral valve stenosis may necessitate surgical repair or replacement of the mitral valve.

Most patients with mitral valve stenosis who require surgery have their mitral valve replaced. A cardiac surgeon replaces the narrowed mitral valve with a mechanical or tissue valve. All the processes of standard heart surgery, such as sternotomy and cardiopulmonary bypass, are included in the treatment.