Mitral valve stenosis - or mitral stenosis - is a
condition in which the mitral valve narrows. This
narrowing causes the valve to not open properly and
to obstruct blood flow between the left chambers of
Your heart - a muscular pump in your chest - has
four valves, which open and close to keep blood
flowing in the proper direction through your heart.
The mitral valve connects the heart's upper-left
chamber (atrium) to the heart's lower-left chamber
When the mitral valve is narrowed (stenotic),
blood can't efficiently move through your heart and
from your heart to the rest of your body. The
condition can leave you fatigued and short of
breath, among other problems.
The main cause of mitral stenosis is a childhood
infection called rheumatic fever, which is related
to strep infections.
Mitral stenosis in people of all ages is
treatable. Treatment depends on the severity and
progression of your condition and signs and
symptoms. If the condition is severe enough, you may
need heart surgery to repair or replace the valve.
Left unchecked, mitral stenosis can lead to serious
Signs and symptoms
You can have mitral stenosis and feel well, or have only minimal signs
and symptoms, for decades. However, mild problems can suddenly get
worse. See your doctor if you develop signs and symptoms of mitral
stenosis, which can include:
especially during times of increased activity
breath, especially with exertion or when you lie down
Swollen feet or
sensations of a rapid, fluttering heartbeat
respiratory infections, such as bronchitis
sometimes with blood-tinged sputum
discomfort or chest pain
Signs and symptoms of mitral stenosis which may resemble those of
other heart or heart valve conditions may appear or worsen anytime you
increase your heart rate, such as during exercise. An episode of rapid
heartbeats may accompany these signs and symptoms. Or they may also be
triggered by pregnancy or other stress on your body such as a
respiratory infection or heart infection.
Signs and symptoms of mitral stenosis commonly include those of
congestive heart failure a complication of mitral stenosis and other
heart problems. Congestive heart failure is a condition in which your
heart can't pump sufficient blood to your body, leaving you fatigued.
Signs and symptoms of mitral stenosis usually develop between the ages
of 20 and 50, but they can occur at any age even during infancy.
Depending on the amount of narrowing, an infant or a child with mitral
stenosis may have no symptoms, may tire easily or may have shortness of
breath with vigorous physical activity.
Mitral stenosis may also produce a number of signs that only your doctor
will be able to find. These may include:
Mitral stenosis won't heal on its own and can be serious. The condition
needs to be evaluated and monitored by your doctor.
The heart, the center of your circulatory system, consists of four
chambers. The two upper chambers, the atria, receive blood. The two
lower chambers, the ventricles, pump blood.
Blood flows through your heart's chambers, aided by four heart valves,
which open and close to let blood flow in only one direction through
The mitral valve which lies between the two chambers on the left side
of your heart consists of two triangular-shaped flaps of tissue called
leaflets. The leaflets of the mitral valve connect to the heart muscle
through a ring called the annulus. Anchoring the mitral valve to the
left ventricle are tendon-like cords, resembling the strings of a
parachute, called chordae tendineae cordis.
Heart valves open like a trapdoor. The mitral valve is forced open when
blood flows from the left atrium into the left ventricle. When all of
the blood has gone through the valve, the leaflets swing closed to
prevent the blood that has just passed into the left ventricle from
flowing backward, in the wrong direction.
defective heart valve is one that fails to either open or close fully.
When a valve doesn't close tightly, blood can flow backward. This
backward flow through a valve is called regurgitation (insufficiency).
When a valve becomes narrowed and flow through it is limited, the
condition is called stenosis.
Mitral stenosis is narrowing of the mitral valve. Many factors can
tighten this passageway between the heart's left-sided chambers,
obstructing blood flow into the heart's left ventricle. Causes of mitral
A complication of strep throat rheumatic fever can damage the
mitral valve, leading to mitral stenosis later in life. Rheumatic
fever can damage the mitral valve in two main ways. The infection
may cause the leaflets of the valve to thicken, limiting the valve's
ability to open. Or the infection may cause the leaflets of the
mitral valve to fuse somewhat together, preventing the valve from
closing tightly and leading to regurgitation. People with rheumatic
fever may have both mitral stenosis and regurgitation.
Some babies are born with a narrowed mitral valve and develop mitral
stenosis early in life. Babies born with this problem usually
require heart surgery to correct the valve. Others are born with a
malformed mitral valve that puts them at risk of developing mitral
stenosis when they're older.
Rarely, growths, blood clots or tumors can block the mitral valve,
mimicking mitral stenosis. Some medications, such as appetite
suppressants and medications that treat migraines may cause
thickening of the mitral valve, which can lead to mitral stenosis.
As you age, excessive calcium deposits can build up around the
mitral valve, which sometimes causes significant mitral stenosis.
In most cases, doctors don't know why a heart valve has failed to
develop properly in a newborn, infant or child. It's not something that
you could have prevented.
Mitral stenosis is less common today than it was several decades ago,
because the most common cause, rheumatic fever, has largely been
eradicated. However, rheumatic fever remains a
frequent problem in developing countries.
Risk factors for mitral stenosis include a history of rheumatic fever
and recurrent strep infections.
Congenital mitral stenosis is rare and even more rare in isolation. It
usually occurs as a component of other heart defects present at birth.
Screening and diagnosis
If you develop signs or symptoms of mitral stenosis for example, if
you experience sudden breathlessness with mild exertion your doctor
may ask you to undergo several types of diagnostic tests.
But first your doctor will ask about your medical history and give you a
physical examination. As part of your examination, he or she listens
carefully to your heart through a stethoscope. Mitral stenosis causes an
abnormal heart sound, called a heart murmur. Normal heart valves open
silently to permit the flow of blood. A narrowed mitral valve can make a
distinct snapping sound followed by a rumbling murmur.
In addition to listening to your heart, your doctor listens to your
lungs and the sounds of your breathing. Your doctor is checking for lung
congestion the buildup of fluid in your lungs that can occur with
From the initial information, your doctor decides which tests to request
to make a diagnosis. For testing, you may be referred to a cardiologist
a doctor who specializes in the study of the heart and its function.
Common tests to diagnose mitral stenosis include:
In this test, patches with wires (electrodes) are attached to your
skin to measure the electrical impulses given off by your heart.
Impulses are recorded as waves displayed on a monitor or printed on
paper. An ECG can give information about your heart rhythm and,
indirectly, heart size. With mitral stenosis, some parts of your
heart may be enlarged and you may have atrial fibrillation, a heart
rhythm irregularity. Your doctor may ask you to walk on a treadmill
or pedal a stationary bike while undergoing an ECG, to see how your
heart responds to exertion.
A Holter monitor is a portable device that you wear to record a
continuous ECG, usually for 24 to 72 hours. Holter monitoring is
used to detect intermittent heart rhythm irregularities that may
accompany mitral stenosis.
An X-ray image of your chest allows your doctor to check the size
and shape of your heart to determine whether the left atrium is
enlarged a possible indicator of mitral stenosis. A chest X-ray
also helps your doctor check the condition of your lungs. Mitral
stenosis may lead to blood backing up in your lungs, which causes
congestion that's visible on an X-ray.
This test uses sound waves to produce an image of your heart. In an
echocardiogram, sound waves are directed at your heart from a
wand-like device (transducer) held on your chest. Sound waves bounce
off your heart and are reflected back through the chest wall and
processed electronically to provide video images of your heart in
motion. An echocardiogram helps your doctor closely examine the
mitral valve. The image shows the structure of the mitral valve and
how it moves during the beating of your heart. Does it open wide to
let blood flow through? Does it close fully? Is it misshapen? With
an echocardiogram, your doctor can also measure the speed and
direction of blood flow through your heart.
This type of echocardiogram allows an even closer look at the mitral
valve. Your esophagus, the tube that runs from your throat to your
stomach, lies close to your heart. In a traditional echocardiogram,
a transducer is moved across your chest. In a transesophageal
echocardiogram, a small transducer attached to the end of a tube is
inserted down your esophagus. Because your esophagus lies close to
your heart, having the transducer there provides a clear picture of
the mitral valve and blood flow through it.
In this procedure, your doctor threads a thin tube (catheter)
through a blood vessel in your arm or groin to an artery in your
heart. A dye injected through the catheter fills your heart's
arteries, and the arteries become visible on an X-ray. This test
gives your doctor detailed information about the health of your
heart. Some catheters used in cardiac catheterization have miniature
devices (sensors) at the tips that can measure pressure within heart
chambers, such as the left atrium.
Cardiac tests such as these help your doctor distinguish mitral stenosis
from other heart conditions, including other problems of the mitral
valve. Mitral regurgitation is a condition in which the mitral valve
doesn't close tightly. Mitral valve prolapse is a disorder in which the
mitral valve sags instead of closes tightly. These conditions may also
If you receive a diagnosis of mitral stenosis, these tests also help
reveal the cause, determine how serious the problem is, and determine
whether the mitral valve can be repaired or if replacement may be
Whatever the cause, a narrowed mitral valve limits blood flow in the
same way a narrow funnel spout limits the flow of fluid through a
funnel. In mitral stenosis, blood has a difficult time flowing from the
left atrium to the left ventricle. Pressure builds up in the left
atrium, and the chamber may enlarge. Blood may back up into your lungs,
leading to lung congestion and shortness of breath. In addition, the
enlarged left atrium may become prone to a heart rhythm irregularity
called atrial fibrillation. In atrial fibrillation, the upper chambers
(atria) of the heart beat chaotically and inefficiently.
Like other heart valve problems, mitral stenosis can weaken your heart
and decrease how efficiently it pumps blood. Mitral stenosis reduces the
amount of blood that flows forward through your heart and out to the
rest of your body.
Left unchecked, mitral stenosis can lead to complications such as:
Congestive heart failure is a condition in which your
heart is weakened and can't pump sufficient blood to meet your
body's needs. A narrowed mitral valve interferes with blood flow
through your heart and from your heart out to the rest of your body.
In addition, pressure builds up in your lungs, leading to fluid
accumulation. Eventually this places a strain on the right side of
the heart, which leads to fluid buildup in either your ankles or
abdomen or both areas.
Mitral stenosis weakens your heart by damaging your
heart's upper-left chamber (atrium). In mitral stenosis, blood has a
difficult time flowing from the left atrium to the left ventricle.
Pressure builds up in the left atrium, and the chamber may enlarge
and thicken. At first this change helps your heart pump more
efficiently, but eventually, it proves damaging to your heart's
overall health. Additionally, pressure can build up in your lungs
and cause pulmonary hypertension.
In mitral stenosis, the stretching and enlargement of your heart's
left atrium may lead to a heart rhythm irregularity called atrial
fibrillation. In atrial fibrillation, the upper chambers of your
heart beat chaotically and rapidly.
Left untreated, atrial fibrillation can put you at risk of blood
clots forming in the upper-left chamber of your heart, where blood
pools in mitral stenosis. Blood clots from your heart may break
loose and travel to other parts of your body, causing serious
problems. For example, a blood clot that travels to your brain and
blocks a blood vessel there could cause a stroke. A transesophageal
echocardiogram can help determine whether blood clots have formed in
a heart with a narrowed mitral valve.
Another possible complication of mitral stenosis is pulmonary edema
a condition in which blood and fluid back up into your lungs. This
causes congestion of the lungs, leading to shortness of breath and,
sometimes, coughing up of blood-tinged sputum.
It may be difficult to understand why you need treatment if you have
mitral stenosis, yet still feel well. If you have severe mitral stenosis
but are in otherwise good health, you need valve repair or replacement
as soon as possible to prevent permanent damage to your heart.
Surgery isn't always needed right away, however. If tests reveal that
you have mild to moderate mitral stenosis and you have no symptoms,
there's generally no need for immediate valve surgery. Instead, your
doctor will talk with you about scheduling checkups to carefully monitor
the valve so that surgery can be done at the appropriate time.
Medications can help ease symptoms of mitral stenosis.
In general, surgery is necessary if and when narrowing becomes severe
and symptoms develop. If at any point you notice symptoms associated
with mitral stenosis, let your doctor know so that you can be evaluated.
Some people never need surgery because they never develop severe mitral
stenosis. For others, the condition progresses and surgery becomes
medications can correct a defect in the mitral valve. However, certain
drugs can minimize symptoms by easing your heart's workload and
regulating your heart's rhythm.
For example, your doctor may prescribe diuretics to reduce fluid
accumulation in your lungs or elsewhere. Anticoagulants can help to
prevent blood clots from forming in a heart with a damaged valve. Your
doctor may also prescribe drugs to treat atrial fibrillation or other
rhythm disturbances associated with mitral stenosis.
If you have mitral stenosis, your doctor may recommend that you take
antibiotics before certain dental or medical procedures. These
procedures may increase the likelihood of bacteria entering your
bloodstream that can cause an infection in your heart (endocarditis).
Endocarditis is an infection of the heart's inner lining the
endocardium. Typically, the infection involves one of the heart valves,
especially if it's already damaged. If the mitral valve is narrowed,
it's more prone to infection than is a healthy valve.
may need valve repair or replacement to treat mitral stenosis. Surgical
This procedure which doesn't involve open-heart surgery uses a
soft, thin tube (catheter) tipped with a balloon to open up the
mitral valve passageway. A doctor guides the catheter through a
blood vessel in your arm or groin to your heart and into your
narrowed mitral valve. However, to reach the mitral valve on the
left side of your heart, doctors actually guide the catheter through
the right side of your heart first and then create a very small hole
in the center of the heart (septum) that separates the right and
left upper chambers of your heart. In some people, this small hole
exists naturally. Through this tiny hole a shortcut surgeons can
more easily reach the mitral valve. Once in position at the mitral
valve, a balloon at the tip of the catheter is inflated. The balloon
pushes open the mitral valve and stretches the valve opening,
improving blood flow. The balloon is then deflated and the catheter
with balloon is guided back out of your body. Once the catheter is
removed, the tiny hole in the heart wall will seal on its own.
Balloon valvuloplasty can relieve mitral stenosis and its symptoms.
But it may not be appropriate if the valve is both tight (stenotic)
and leaky (regurgitant). It's also not performed if there's a blood
clot in a chamber of your heart, because of the risk of dislodging
it. Balloon valvuloplasty may improve the blood flow through the
valve for a time. However, over time the narrowing may recur.
Surgery to repair without replacing the mitral valve
may be an option. For example, some infants are born with a mitral
valve in which the leaflets of the valve are fused together. Or in
adults, the valve leaflets become scarred and fused. By surgically
separating or shaving back these leaflets a procedure called
valvotomy or commissurotomy doctors can eliminate mitral stenosis
and improve blood flow. Or valve repair at any age may involve
removing obstructions on or near the mitral valve. This helps clear
the valve passageway. The surgeon may also make adjustments to the
cords that anchor the valve leaflets to your heart, to improve valve
function. Valve repair can be done through open-heart surgery,
closed-heart surgery during which the surgeon operates from a
small opening in your chest at the side of your heart or with the
aid of catheters. You may need the procedure repeated if you
redevelop mitral stenosis.
Your surgeon removes the narrowed mitral valve and
replaces it with a mechanical valve or a tissue valve from a pig,
cow or human cadaver donor. Pigs and cows have heart tissue similar
to that of humans. Mechanical valves, made from metal, are durable,
but they carry the risk of blood clots forming on or near the valve.
If you receive a mechanical mitral valve, you must take an
anticoagulant medication, such as warfarin (Coumadin), for life to
prevent blood clots. Tissue valves rarely raise your risk of blood
clots, but they tend to wear out faster than mechanical valves do
and may need to be replaced. Your doctor can discuss with you the
types of heart valves. The results with either tend to be very good.
Mitral valve surgery may involve open-heart surgery. For open-heart
surgery, you're given a general anesthetic. Through an incision the
length of your breastbone (sternum), your heart is exposed and connected
to a heart-lung machine that assumes your breathing and blood
circulation function during the procedure. Your surgeon then replaces
the narrowed mitral valve. After the operation, which lasts several
hours, you spend one or more days in an intensive care unit, where your
heart function and general recovery are closely monitored.
Surgeons are working on developing less invasive techniques to treat
valve disorders, such as repairing mitral valves using endoscopy, which
uses smaller incisions. Such procedures, however, aren't widely
Mitral stenosis can be completely eliminated with surgery. However, you
may continue to be at risk of arrhythmias even after you've been treated
for mitral stenosis. You may need to take medications to lower that
risk. In addition, you may continue to experience heart symptoms such as
shortness of breath despite treatment.
The only possible way to prevent mitral stenosis is to prevent rheumatic
fever. You can do this by making sure you see your doctor when you have
a sore throat. Untreated strep throat can develop into rheumatic fever.
Fortunately, strep throat is easily treated with antibiotics.
You can help prevent the complication endocarditis, an infection of the
mitral valve and inner heart, by taking antibiotics before certain
dental and medical procedures. Ask your doctor if and when you should
take antibiotics to prevent endocarditis.
To maximize your quality of life if you have mitral stenosis, your
doctor may recommend that you:
Food doesn't directly affect the degree of mitral stenosis. However,
salt in food may increase the pressure on your heart. So don't add
salt to your food, and avoid foods high in sodium. Read the labels
on foods for sodium content and ask for low-salt foods when you eat
out. If you have questions about salt in your diet, ask your doctor.
Excess weight may make you short of breath and may complicate heart
surgery if you ever need it. Keep your weight within a range
recommended by your doctor.
blood pressure regularly.
Control of blood pressure is extremely important if you have mitral
Cut back on
Irregular heartbeats (arrhythmias) may occur in people with mitral
stenosis. Arrhythmias may get worse if you consume caffeine. Ask
your doctor about drinking beverages with caffeine, such as coffee
or soft drinks.
medical attention if you notice frequent palpitations or feel your
Fast heart rhythms that aren't treated can lead to
rapid deterioration in people with mitral stenosis.
Cut back on
Heavy alcohol consumption can cause arrhythmias and can make
symptoms worse. If you have mitral stenosis, ask your doctor about
the effects of drinking alcohol.
Physical activity may help to keep your body fit and may help you to
recover faster if you ever need heart surgery. Your doctor usually
will give you guidelines for your exercise program. Don't
stop exercising if you have mitral stenosis. However, if you find
that you're unable to do things because of mitral stenosis, talk to
See your doctor
Establish a regular evaluation schedule with your cardiologist.
Receive regular dental care, following recommendations for the
prevention of endocarditis for any dental procedure.
If you're a woman with mitral stenosis, discuss family planning with
your doctor before you become pregnant, because your heart works harder
during pregnancy. How a heart with mitral stenosis tolerates this extra
work depends on the degree of stenosis and how well your heart pumps.
Should you become pregnant, your cardiologist and obstetrician should
evaluate you throughout your pregnancy, labor and delivery, and after