Definition

Mitral stenosis is a narrowing of the mitral valve in the heart. The mitral valve is in the left side of the heart between the upper and lower chambers of the heart. When working properly, the valve helps to keep blood flowing in the right direction from the upper to the lower chambers.

Mitral stenosis makes it difficult for blood to move from the upper and lower chambers. This means there is less blood for the lower chamber to pump out to the body. The blood can also back up in the upper chamber and push back into the lungs.

Causes

The most common cause of mitral stenosis is rheumatic fever. This infection may develop after strep throat or scarlet fever. It can scar the heart valves. Mitral stenosis may develop 5-10 years after this infection occurs.

Less common or rare causes include:

• Birth defect
• Blood clots
• Tumors
• Infective endocarditis
• Other growths that block blood flow through the mitral valve

Risk Factors

The main risk factor for mitral stenosis is rheumatic fever. Other risk factors may include:

• Being born with mitral valve problems
• Having other health problems that affect blood flow in the heart

Symptoms

Symptoms are caused by the problems with blood flow and may include:

• Difficulty breathing, especially during exercise and when lying flat
• Waking up short of breath in the middle of the night
• Tiredness
• Sensation of rapid or irregular heartbeat
• Cough with exertion
• Coughing up blood
• Swelling of the legs or feet
• Frequent respiratory infections
• Lightheadedness, fainting
• Chest pain, like squeezing, pressure, or tightness (rare)

Diagnosis

You will be asked about your child’s symptoms and medical history. A physical exam will be done.

Images may be taken of your child’s heart. This can be done with:

• Echocardiogram
• Chest x-ray
• Transesophageal echocardiogram —a tube that runs from the mouth into the stomach to better examine the mitral valve
• Cardiac catheterization

Your child’s heart function may also be tested with:

• Electrocardiogram (ECG, EKG)
• Stress test

Treatment

If your child has mild mitral stenosis, immediate treatment may not be needed. Your child’s condition will be monitored to look for potential problems. Other treatment options include:

Prevention

Most cases of mitral stenosis can be prevented by preventing rheumatic fever:

• Treat strep throat infections right away to avoid rheumatic fever, which can cause scarring of the heart valve.
• Always make sure your child finishes all of the antibiotics given, even if symptoms improve.

National Heart, Lung, and Blood Institute http://www.nhlbi.nih.gov

Canadian Family Physician http://www.cfp.ca

Mitral valve abnormalities. Seattle Children’s Hospital website. Available at:
http://www.seattlechildrens.org/medical-conditions/heart-blood-conditions/mitral-valve-abnormalities-symptoms/
Accessed November 3, 2014.

Shipton B, Wahba H. Valvular heart disease: review and update. Am Fam Physician. 20011;63:2201.