|Prolapse, Mitral Valve
Mitral valve prolapse (MVP) is a common heart disorder. It occurs when the valve between your heart's left upper chamber (left atrium) and the left lower chamber (left ventricle) doesn't close properly. When the left ventricle contracts, the valve's leaflets bulge (prolapse) upward or back into the atrium. Mitral valve prolapse sometimes leads to blood leaking backward into the left atrium, a condition called mitral valve regurgitation.
Mitral valve prolapse affects slightly more than 2 percent of adults in the United States. Men and women appear to develop MVP in similar numbers.
In most people, mitral valve prolapse is harmless and doesn't require treatment or changes in lifestyle. It also doesn't shorten your life expectancy. In some people with mitral valve prolapse, however, the progression of the disease requires treatment.
When your heart is working properly, the mitral valve closes during contraction of the left ventricle to prevent blood from flowing back into your heart's upper left chamber (left atrium). But in some people with MVP, the mitral valve malfunctions. In these people, the mitral valve leaflets are abnormal with extra tissue, bulging (prolapsing) like a parachute into their left atrium each time the heart contracts. The bulging may keep the valve from closing tightly. This may not cause problems if only a small
amount of blood leaks back into the atrium. When blood leaks backwards through the valve, it's called mitral regurgitation (MR). MR can cause symptoms.
Another name for mitral valve prolapse is click-murmur syndrome. When a doctor listens to your heart using a stethoscope, he or she may hear a clicking sound as the valve's leaflets billow out, followed by a murmur resulting from blood flowing back into the atrium. Other names to describe mitral valve prolapse include:
- Barlow's syndrome
- Floppy valve syndrome
- Ballooning mitral valve syndrome
Mitral valve prolapse can be inherited, with the disorder frequently running in families. People with Marfan syndrome as well as those with connective tissue disorders have an increased risk of MVP. Other conditions that are sometimes linked to mitral valve prolapse include Ehlers-Danlos syndrome, adult polycystic kidney disease and Ebstein's anomaly.
If you have mitral valve prolapse, the flaps of your mitral valve may be oversized or thickened. People with MVP are often thin and have curvature of the spine (scoliosis) or they may have defects in the bones of their chest wall.
When to seek medical advice :
If you develop what may appear to be symptoms of mitral valve prolapse, contact your doctor. Many other conditions cause the same symptoms as mitral valve prolapse, so only an examination by your doctor can confirm a diagnosis. If you've already been diagnosed with this disorder, see your doctor if your symptoms worsen.
Although mitral valve prolapse is a lifelong disorder, many people with this condition never have symptoms. When diagnosed, people may be surprised to learn that they have a heart abnormality.
When signs and symptoms do occur with mitral valve prolapse, it's typically because blood is leaking backward through the valve (regurgitation). Symptoms can vary widely from one person to another. They tend to be mild, develop gradually and may include :
- A racing or irregular heartbeat (arrhythmia)
- Dizziness, lightheadedness
- Difficulty breathing or shortness of breath, often when lying flat or during physical exertion
- Chest pain that's not associated with a heart attack or coronary artery disease
Doctors may diagnose mitral valve prolapse at any age. Your doctor is most likely to detect mitral valve prolapse during a routine examination of your heart using a stethoscope. If mitral valve prolapse is present, he or she may hear abnormal sounds, such as a characteristic clicking noise that suggests mitral valve prolapse. If there's significant mitral regurgitation, then your doctor will also hear a heart murmur.
An echocardiogram is usually done to confirm the diagnosis. An echocardiogram is a noninvasive, ultrasound evaluation of your heart. This test uses high-frequency sound waves to create images of your heart and its structures, including the mitral valve itself and the flow of blood through it. The amount of leakage (regurgitation) can be measured.
In some cases, you may need to undergo additional tests to provide more details about your heart's valves and help in the diagnosis, including ruling out other conditions of the heart.
If you have mitral valve regurgitation but don't have symptoms, your doctor may suggest you return for examinations to monitor your condition every three to five years. The need for follow-up will be based on the details of your case, including the amount of leakage. If, however, you have severe regurgitation, your doctor may suggest surgery to repair your valve.
Although most people with mitral valve prolapse never have problems, complications can occur. Complications tend to occur in middle-aged or older adults. They may include :
- Mitral valve regurgitation. The most common problem is mitral valve regurgitation (mitral insufficiency) — a condition in which the valve is particularly leaky and allows excessive blood back into the left atrium. Having high blood pressure or being overweight or obese increases your risk of mitral valve regurgitation. If the regurgitation is severe, surgery may be recommended to repair or even replace the valve in order to prevent the development of complications, such as heart failure.
- Heart valve infection (endocarditis). The inside of your heart contains four chambers and four valves lined by a thin membrane called the endocardium. Endocarditis is an infection of this inner lining. An abnormal mitral valve increases the likelihood of acquiring bacterial endocarditis, which can further damage the mitral valve. Because of the risk of developing endocarditis, antibiotics may be given to people with MVP who have significant mitral valve regurgitation before dental procedures and certain types of surgery.
- Heart rhythm problems (arrhythmias). Irregular heart rhythms can occur in people with mitral valve prolapse. These most commonly occur in the upper chambers of the heart, and while they may be bothersome, they aren't usually life-threatening. Doctors have reported cases of sudden cardiac death associated with MVP; however, such fatalities are extremely rare and are not necessarily related to the valve problem. When fatalities do occur, these sudden deaths appear to result from an arrhythmia. People with severe mitral regurgitation, or severe deformity of their mitral valve, are most susceptible to serious rhythm problems.
Most people with mitral valve prolapse, particularly people without symptoms, don't require treatment.
If you develop symptoms, your doctor might prescribe certain medications to treat MVP-related chest pain, heart rhythm abnormalities or other complications. Some medications you might be prescribed include :
- Beta blockers. These drugs help prevent irregular heartbeats. They work by blocking the effects of the hormone epinephrine, also known as adrenaline. As a result, the heart beats more slowly and with less force, thereby reducing blood pressure. Beta blockers also help blood vessels relax and open up to improve blood flow.
- Aspirin. If you have mitral valve prolapse and have a history of strokes, your doctor might prescribe aspirin to reduce the risk of blood clots.
- Prescription anticoagulants (blood thinners). These medications — warfarin (Coumadin) is commonly used — prevent your blood from clotting. If you have atrial fibrillation, a history of heart failure or a history of strokes, your doctor may suggest these drugs. They must be taken exactly as prescribed.
Surgical treatment for mitral valve prolapse
Though most people with mitral valve prolapse don't need surgery, your doctor may suggest surgery if you have severe mitral valve regurgitation with or without symptoms. The risk of severe mitral regurgitation is enlargement of your heart's main pumping chamber (the left ventricle). This can eventually weaken your heart, preventing it from effectively pumping blood. If regurgitation goes on too long your heart may be too weak for surgery.
If your doctor suggests surgery, there are two main options, repair or replacement of the mitral valve.
- Valve repair. Mitral valve repair is a surgery to preserve your own valve. Your mitral valve 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. The surgeon can modify the original valve (valvuloplasty) to eliminate backward blood flow. Surgeons can repair the valve by reconnecting valve leaflets or by removing excess valve tissue so that the leaflets can close tightly. Sometimes repairing the valve includes tightening or replacing the ring around the valve (annulus). This is called an annuloplasty.
- Valve replacement. Valve replacement is done when valve repair isn't possible. In valve replacement surgery, the damaged mitral valve is replaced by an artificial (prosthetic) valve. The two types of artificial valves are mechanical and tissue. Mechanical valves, which are made of metal, may last a long time. However, if you have a mechanical valve, you must use an anticoagulant medication, such as warfarin (Coumadin), for the rest of your life to prevent blood clots from forming on the valve. If a blood clot forms on the valve and breaks free, it could travel to your brain and cause a stroke. Tissue valves are made from biologic tissue such as a pig's heart valve. These kinds of valves are called bioprostheses. They may wear out over time and need replacement. However, an advantage of the tissue valve is that you don't have to use long-term anticoagulant medication.
Current guidelines from the American Heart Association indicate repairing, rather than replacing, your mitral valve is usually the best option for most people with MVP who need surgery. The success of mitral valve repair depends on the expertise of the surgeon. Valve repair or replacement operations are best done by surgeons experienced in doing them.
Mitral valve repair or replacement requires open heart surgery, done under general anesthesia. Through an incision, usually through your breastbone (sternum), your heart is exposed and connected to a heart-lung machine that assumes your breathing and blood circulation functions during the procedure. Your surgeon then replaces or repairs the valve. After the operation, you'll spend one or more days in an intensive care unit, where your heart function and general recovery are closely monitored. Less invasive ways of repairing or replacing the mitral valve are also being studied, but these procedures aren't widely available yet.
Depending on your age and risk factors for coronary artery disease, your doctor may recommend cardiac catheterization and coronary angiograms before surgery. During a cardiac catheterization, a long, thin, flexible plastic tube (catheter) is inserted into your body. Dye is injected into the blood vessels of your heart. The dye is visible by X-ray machine. The machine rapidly takes a series of X-ray images (angiograms), offering a detailed look at your heart arteries to determine if you need coronary artery bypass at the same time as your valve surgery. Pressures in the heart's chambers may be measured, particularly if there is any concern about high blood pressure in the lung arteries (pulmonary hypertension) that might influence the decision to proceed with surgery.
Keeping others informed
Make sure your dentist or dental hygienist knows that you have mitral valve prolapse if you need dental work that's likely to cause gum bleeding, including routine cleaning. Also, tell your surgeon about your mitral valve prolapse before an operation such as a tonsillectomy, gallbladder surgery or prostate surgery. You may need to take antibiotics before the treatment or surgery in order to reduce the risks of a heart infection (endocarditis). Antibiotics can destroy most of the bacteria that enter and travel through your bloodstream, thus preventing an infection of the heart valve.
Precautions during pregnancy
If you're pregnant and have mitral valve prolapse, your chances of a successful, uncomplicated pregnancy are good. Even so, doctors sometimes recommend antibiotics during childbirth if there's a risk of an infection that could affect the mitral valve.
You can't prevent mitral valve prolapse. However, you can lower your chances of developing the complications associated with it by making sure you take your medications, if any, as directed. Also, remember to let your doctor or dentist know you have mitral valve prolapse so that they can evaluate whether you need antibiotics to help prevent infections of your heart valve.