Mitral Stenosis

What is Mitral Stenosis?

Mitral stenosis is a valvular heart disease characterized by the narrowing of the mitral valve which causes movement of oxygenated blood from the left atrium to the left ventricle to be reduced. The mitral valve dysfunction eventually leads to blood backing up in the left atrium, in the blood vessels in the lungs, and in the right side of the heart causing pulmonary hypertension and right heart failure. Mitral valve stenosis is predominantly caused by rheumatic fever and is more prevalent in women. It usually takes several decades for clinically relevant stenosis to appears after untreated rheumatic fever. What is Mitral Stenosis?

What is the epidemiology of Mitral Stenosis?

Most cases of mitral stenosis are caused by rheumatic heart disease worldwide but the incidence of rheumatic disease in the United States and other developing countries is declining with an estimated incidence of 1 in 100,000.  Most mitral stenosis in the United States occurs in patients who have emigrated here from countries where rheumatic fever is still commonplace. In Africa, for example, the prevalence is 35 cases per 100,000. Antibiotics and socioeconomic factors are believed to play a role in the decline of rheumatic carditis over the years.

What causes Mitral Stenosis?

  • Rheumatic Fever: The most common cause
  • Calcification the mitral valve: Associated with aging and common in the elderly
  • Radiation treatment to the chest
  • Congenital heart disease
  • Systemic lupus erythematosus and rheumatoid arthritis are rare causes of mitral stenosis

What are the symptoms of Mitral Stenosis?

People with mitral stenosis are usually asymptomatic until the disease progress and the common symptoms are:

  • Dyspnea on exertion known as trouble breathing – This is the most common symptom. Trouble breathing initially occurs during physical activities but as the disease progress, people can have trouble breathing at rest as well.
  • A severe cough, or coughing up blood or mucus
  • Feeling tired
  • Swelling in the legs
  • Atrial fibrillation
  • Blood clots forming in the left atrium

How to diagnose Mitral Stenosis?

A careful medical history and physical examination are essential in the diagnosis of mitral stenosis. During a physical examination, a healthcare provider listens to the heart with a stethoscope and abnormal heart sound is heard as the blood tries to pass through the narrowed valve opening from the left atrium into the left ventricle. It usually makes a snapping sound as it opens to allow blood into the left ventricle. The diagnosis of mitral stenosis is confirmed by echocardiogram which uses sound waves to create an image of the heart as it beats and allows for visualization of the narrowed heart valve narrowed.  Additional diagnostic testing such as an electrocardiogram (ECG) and chest x-rays also provide useful information.

What are the treatments of Mitral Stenosis?

Treatment is not required for people with no symptoms. Careful evaluation and monitoring of the disease progression are sufficient.

People with symptoms are treated with medications which include:

  • Diuretics
  • Beta-blockers/ Calcium channel blockers
  • Nitrates
  • Digoxin
  • Anticoagulant to prevent blood clot formation

Valve repair or replacement may be required if symptoms persisted after pharmacotherapy and it includes: 

  • Balloon valvotomy. This procedure is used to increase the opening of a narrowed valve using a catheter with a balloon on the tip. The catheter is threaded into the heart and the balloon is inflated to separate the valve cusps.

Transcatheter mitral valve replacement: This procedure involves replacing the narrowed valve with a new valve made from metal, animal tissue, or another person.  Antibiotics are given to people with mitral valve replacement before dental, surgical or medical procedure to prevent infective endocarditis

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