Definition Mitral stenosis is an abnormal narrowing of the mitral valve, which is one of the heart valves. This "tight" valve obstructs the flow of blood within the heart.
What is going on in the body? The human heart has 4 chambers. In the normal heart, the mitral valve helps control blood flow between 2 of these chambers, the left atrium and the left ventricle. In mitral stenosis, the valve does not open enough to allow proper blood flow into the left ventricle. This abnormal blood flow can cause changes and damage to the heart and lungs.
What are the signs and symptoms of the condition? Some individuals with mitral stenosis have no symptoms at all. However, this condition may cause:
fatigue, which is often the first symptom a person feels
a heart murmur, or abnormal sound which may be heard by the doctor with a stethoscope
What are the causes and risks of the condition? Most cases of mitral stenosis are due to the long-term consequences of rheumatic fever. Rheumatic fever can occur after group A streptococcal infections of the throat that are not treated with antibiotics. If this infection is not treated properly, mitral stenosis may occur years later. Rare causes of mitral stenosis include:
inflammation of the mitral valve from various illnesses
The risks of mitral stenosis are related to the "tightness" of the valve. A person with mitral stenosis may live a lifetime with no problems. However, a person with severe mitral stenosis is at increased risk of permanent heart damage. arrhythmias, or irregular heartbeats that can lead to blood clots, may occur.
What can be done to prevent the condition? In children with certain throat infections, proper antibiotic treatment can prevent this condition. Other causes are not usually preventable.
How is the condition diagnosed? The history and physical examination often cause a doctor to suspect this condition. A heart murmur can often be heard with a stethoscope. A heart tracing, or ECG, and chest x-ray may show certain abnormalities. Special x-ray tests, such as a cardiac catheterisation, can determine the severity of the condition and help guide treatment.
What are the long-term effects of the condition? Long-term effects depend on the tightness of the valve. A person with mild mitral stenosis may have no long-term effects. A person with severe mitral stenosis may have serious heart and lung complications, including irregular heartbeats, blood clots, and permanent heart damage.
What are the risks to others? Mitral stenosis is not contagious and poses no risk to others. However, the infection that causes rheumatic fever, the most common cause of mitral stenosis, is contagious.
What are the treatments for the condition? A person with no symptoms or heart problems may be advised to take antibiotics before surgery or dental work. In general, treatment depends on the severity of the condition and which problems have occurred. Heart medications may be used to slow the heart or treat irregular heartbeats. Medications used to prevent blood clots may be used in a person with Arrhythmias. A person who continues to have symptoms despite medical therapy may have heart valve surgery to fix the valve or replace it with an artificial one.
What are the side effects of the treatments? A person treated with medication may have side effects related to the medications used. All surgery carries a risk of bleeding, infection, and reactions to the anaesthesia medication. Valve repair may need to be repeated or in time may require valve replacement. A person with an artificial valve may require medication to prevent blood clots, for life in some cases. An artificial valve is subject to wear and tear and may need replacement after years of use.
What happens after treatment for the condition? In many cases, treatment does not end. The person usually returns to normal activity after recovery from surgery. Medications to prevent blood clots and treat abnormal heartbeats may be needed.
How is the condition monitored? Regular visits to the doctor are often advised. Repeat testing, such as an ultrasound of the heart known as an echocardiogram, may be done to make sure the valve is stable. Medications for abnormal heartbeats and blood clots need to be monitored as well.
Author: Eric Berlin, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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