Regurgitation, Mitral Valve
Mitral valve regurgitation — or mitral regurgitation — is a condition in which the mitral valve doesn't close tightly, which allows blood to flow backward in your heart.
When the mitral valve doesn't function properly, blood can't move through your heart or to the rest of your body as efficiently. Mitral valve regurgitation is also called mitral insufficiency, or incompetence. The condition can leave you fatigued and short of breath. As many as one in five people over age 55 have some degree of mitral valve regurgitation.
Treatment of mitral valve regurgitation depends on the severity and progression of your condition and signs and symptoms. You may need heart surgery to repair or replace the valve. Left unchecked, severe mitral valve regurgitation can lead to congestive heart failure or serious heart rhythm irregularities (arrhythmias).
Your heart, which is 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. These valves open and close allowing blood to flow in only one direction through your heart. The four heart valves are :
- Tricuspid valve
- Pulmonary valve
- Mitral valve
- Aortic valve
The mitral valve, which lies between the two left chambers 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 leaflets of the mitral valve open when the left atrium contracts, forcing blood through the leaflets and into the left ventricle. When the left atrium relaxes between heart contractions, the flaps shut to prevent blood that has just passed into the left ventricle from flowing backward, in the wrong direction.
When working properly, heart valves open and close fully. In mitral valve regurgitation, the mitral valve doesn't close tightly. So, with each heartbeat, some blood from the left ventricle flows backward into the left atrium, instead of forward into the aorta. Regurgitation refers to this backflow of blood through the heart valve.
Any condition that damages a valve can cause regurgitation. Mitral valve regurgitation has several causes, including :
- Mitral valve prolapse. Mitral valve prolapse is a condition in which the leaflets and supporting cords of the mitral valve weaken. The result is that with each contraction of the left ventricle, the valve leaflets bulge (prolapse) up into the left atrium. This common heart defect may prevent the mitral valve from closing tightly and lead to regurgitation. However, mitral valve prolapse is common and the vast majority of people who have it never develop severe regurgitation.
- Damaged cords. Mitral valve regurgitation may result from damage to the cords that anchor the flaps of the mitral valve to the heart wall. Over time, these cords may stretch or suddenly tear, especially in people with mitral valve prolapse. A tear of these cords can cause substantial leakage through the mitral valve and may require heart surgery to repair.
- Rheumatic fever. Rheumatic fever — a complication of strep throat and once a common childhood illness in the United States — can damage the mitral valve, leading to mitral valve regurgitation 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. This results in narrowing of the valve, a condition known as mitral valve stenosis. The infection may cause scarring of the mitral leaflets leading to regurgitation. People with rheumatic fever, which is still common in countries where antibiotic use isn't common, may have both mitral valve stenosis and mitral valve regurgitation.
- Endocarditis. The mitral valve may be damaged by endocarditis, an infection inside the heart that can involve heart valves.
- Deterioration of the valve with age. The mitral valve opens and shuts tens of thousands of times every day of your life. Sometimes age-related wear and tear on the valve causes mitral valve regurgitation.
- Prior heart attack. A heart attack can damage the area of the heart muscle that supports the mitral valve, affecting the function of the valve. In fact, if the damage is extensive enough, a heart attack may result in sudden and severe mitral valve regurgitation.
- Congenital heart defects. Some babies are born with defects in their heart, including a mitral valve that's leaky.
Severe mitral valve regurgitation — of any cause — can weaken your heart. When the left ventricle contracts in a heart with mitral valve regurgitation, some blood flows backward into the left atrium instead of flowing forward into the aorta. As a result, less blood flows out to the rest of your body. In response, the left ventricle may enlarge so that it can pump more blood with each heartbeat. At first this adaptation helps your heart beat with more force. But eventually, the change weakens your heart and may cause congestive heart failure and heart rhythm irregularities, such as atrial fibrillation.
Risk factors :
Several factors can increase your risk of mitral valve regurgitation, including :
- A history of mitral valve prolapse or mitral valve stenosis. However, having either condition doesn't necessarily mean you'll develop mitral valve regurgitation. In fact, most people with mitral valve prolapse never develop severe regurgitation.
- A past heart attack. A heart attack can damage your heart, affecting the function of the mitral valve.
- Use of certain appetite suppressants. People who took fenfluramine or dexfenfluramine for more than four months may have an increased risk.
- Infections, such as endocarditis or rheumatic fever. Infections can damage the mitral valve.
- Congenital heart disease. Some people are born with an abnormal mitral valve prone to regurgitation. Often babies born with heart defects may have more than one problem, such as a hole in the upper chambers of the heart (atrial septal defect) and an abnormal mitral valve.
- Age. By middle age, many people have some degree of mitral valve regurgitation caused by natural deterioration of the valve. However, mitral valve regurgitation progresses to cause symptoms in only a small percentage of older adults.
When to seek medical advice :
If you develop signs and symptoms that suggest mitral valve regurgitation or another problem with your heart, see your doctor right away. Sometimes, the first indicators of mitral valve regurgitation are actually those of its complications, including congestive heart failure. Congestive heart failure is a condition in which your heart can't pump sufficient blood to the rest of your body, causing shortness of breath, fluid buildup and fatigue.
However, mitral valve regurgitation is commonly discovered earlier, during a routine examination when your doctor listens to the sounds of your heart with a stethoscope. Mitral valve regurgitation can cause an abnormal heart sound (heart murmur). Your doctor may have already informed you that you have a heart murmur caused by mitral valve regurgitation.
When mild, mitral valve regurgitation may never pose a serious threat to your health. But when severe, mitral valve regurgitation may cause heart complications and require surgery to correct.
Signs and symptoms of mitral valve regurgitation depend on how severely and quickly the condition develops. Most often mitral valve regurgitation is mild and develops slowly. Because you may have no symptoms for decades, you may be completely unaware that you have this condition.
When signs and symptoms do develop, they may do so gradually because the heart is able to compensate for the valve defect for some time. Mitral valve regurgitation is often first suspected when your doctor hears a new heart murmur. Sometimes, however, the disorder develops quickly, and you may experience the abrupt onset of more severe signs and symptoms. Indicators of mitral valve regurgitation include :
- Shortness of breath, especially with exertion or when you lie down
- Fatigue, especially during times of increased activity
- Cough, especially at night or when lying down
- Heart palpitations — sensations of a rapid, fluttering heartbeat
- Swollen feet or ankles
- Heart murmur
- Excessive urination
If you have signs and symptoms of mitral valve regurgitation, you may undergo several types of diagnostic tests. But first your doctor will ask you about your general health, including your symptoms, prior tests and history of heart disease in your family.
Next, your doctor performs a physical examination. He or she listens to your heart sounds with a stethoscope. Mitral valve regurgitation produces a distinct heart murmur. The murmur is the sound of blood leaking backward through the mitral valve.
With this information, your doctor decides which tests to request so that he or she can make a diagnosis and develop a treatment plan. You may be referred to a cardiologist — a doctor who specializes in the study of the heart and its function. Common tests used to diagnose heart valve problems include :
- Echocardiogram. 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. The 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 get a close look at the mitral valve and how well it is — or isn't — working. A specific type of echocardiogram, a Doppler echocardiogram, may be used. It allows more precise measurements of the volume of blood flowing backward through the mitral valve.
- Chest X-ray. With an X-ray of your chest, your doctor can see the size and shape of your heart to determine whether the left ventricle is enlarged. A chest X-ray also allows your doctor to evaluate your lungs. Mitral valve regurgitation may result in blood backing up into your lungs, which causes congestion that's visible on an X-ray.
- Electrocardiogram (ECG). 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 gives information about heart rhythm and, indirectly, heart size. With mitral valve regurgitation, the left ventricle may be enlarged and you may have heart rhythm irregularities (arrhythmias).
- Holter monitor. 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 be associated with mitral valve regurgitation.
- Transesophageal echocardiogram. This type of echocardiogram allows an even closer look at the mitral valve. The 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 the esophagus. Because the esophagus lies close to your heart, having the transducer there provides a clearer picture of the mitral valve and blood flow through it.
- Exercise tests. Various exercise tests can help measure your tolerance for activity and check your heart's response to exertion (exercise).
- Cardiac catheterization. In this procedure, a doctor threads a thin tube (catheter) through a blood vessel in your arm or groin into your heart. The catheter is used to deliver dye into the heart chambers and the blood vessels of your heart. The dye, appearing on X-ray images as it moves through your heart, gives your doctors detailed information about your heart and heart valves. Some catheters used in cardiac catheterization have miniature devices (sensors) at the tips that can measure pressure within heart chambers, such as the left ventricle.
Mitral valve regurgitation puts you at risk of endocarditis, an infection of the heart's inner lining (endocardium). Typically, the infection involves one of the heart valves, especially if it's already damaged. If the mitral valve is damaged, it's more prone to infection than is a healthy valve. You can develop endocarditis when bacteria from another part of your body spread through the bloodstream and lodge in your heart. If you have mitral valve regurgitation, your doctor may recommend that you take antibiotics before certain dental or medical procedures that may increase the likelihood of bacteria entering your bloodstream and causing an infection in your heart.
When it's mild, mitral valve regurgitation may never pose a serious threat to your health. But when it's severe, mitral valve regurgitation may lead to these complications :
- Congestive heart failure. In congestive heart failure, your heart is unable to pump sufficient blood to meet your body's needs. Fluid and pressure build up in your lungs as a result of mitral valve regurgitation. This can put a strain on the right side of your heart, leading to ankle swelling (edema). People with congestive heart failure experience shortness of breath and fatigue and may wake up at night feeling short of breath.
- Atrial fibrillation. This is an irregular heart rhythm in which your heart's upper chambers (atria) beat chaotically and rapidly. Atrial fibrillation is worrisome because it can lead to blood clots forming in your heart. These blood clots may break loose from your heart and travel through your bloodstream to your brain, causing a stroke. Other irregular heartbeats (heart arrhythmias) also may occur in people with mitral valve regurgitation.
Treatment for mitral valve regurgitation depends on the severity and progression of your condition. Treatment focuses on maximizing your heart's function, minimizing your signs and symptoms, and avoiding future complications.
Some people, especially those with mild regurgitation, need no specific treatment. However, even if you don't have signs and symptoms with mitral valve regurgitation, the condition requires monitoring by your doctor. You'll need regular evaluations, with the frequency depending on the amount of regurgitation.
Observation isn't the same as ignoring the condition. Actively observing the stability or the progression of the disorder is important so that you can receive the right treatment at the right time.
No medication can correct a deformity of a mitral valve. Medications such as diuretics are available to relieve fluid accumulation in your lungs or legs, which can accompany mitral valve regurgitation. High blood pressure makes mitral valve regurgitation worse, so if your blood pressure is elevated your doctor may prescribe medication to help lower it. Following a low-salt diet helps prevent fluid buildup and helps control blood pressure. Antibiotics are used to help prevent endocarditis. If you have mitral valve regurgitation, always follow precautions to prevent endocarditis. Ask your doctor or nurse for these guidelines.
Your mitral valve may need to be surgically repaired or replaced. Naturally, if you feel well, you may question the need for open heart surgery, if suggested by your doctor, to correct your mitral valve. Strange as it may seem, you can have very bad mitral valve regurgitation and yet feel well. This is because the heart is generally very adept at counteracting deficiencies caused by a leaky mitral valve.
However, the problem is that if the valve isn't repaired or replaced, the strength of your heart muscle may continue to decline so far that even once the valve is operated on, the problem with the weakened pump remains. Additionally, if damage to your heart becomes too severe, surgery can't be safely performed. So it's important to have surgery early enough that your heart doesn't become permanently weakened.
Over the years, extraordinary progress has been made in surgery to repair the mitral valve, minimizing the risk of surgery. Discuss the risks and benefits of surgery with your doctor. Surgical procedures include :
- Valve repair. Mitral valve repair is a surgery to preserve your own valve. 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, the valve won't work properly. If a clot breaks free of the valve, it could lodge in an artery to your brain, blocking blood flow to your brain and causing a stroke. Tissue valves are made from biologic tissue such as a pig's valve. These kinds of valves are called bioprostheses. They may wear out over time and may need replacement in another operation. However, an advantage of the tissue valve is that you don't have to use long-term anticoagulant medication. Your doctor can discuss with you the types of heart valves. The results with either type of valve tend to be very good.
Mitral valve repair or replacement generally involves open heart surgery, done under general anesthesia. 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 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 techniques
Surgeons are working on developing less invasive techniques to treat valve disorders, such as repairing mitral valves using endoscopy, which uses smaller incisions, or possibly using robotic surgery to repair the mitral valve. Such procedures, however, aren't widely available. Eventually it may even be possible to replace the mitral valve using cardiac catheterization techniques that don't require open heart surgery.
Mitral valve regurgitation can be eliminated with surgery. The prognosis is generally good after surgery. However, let your doctor know if you develop new or worsening signs and symptoms after treatment. Mitral valve regurgitation can recur.
Some people, especially those with mild regurgitation, need no specific treatment. However, even if you don't have signs and symptoms with aortic valve regurgitation, schedule regular evaluations with your doctor. Observation isn't the same as ignoring the condition. Actively observing the stability or the progression of the condition is important so that you can receive the right treatment at the right time.
No medication can eliminate aortic valve regurgitation. However, your doctor may prescribe certain medications to reduce the degree of aortic valve regurgitation, control blood pressure and try to prevent fluid buildup. If you have aortic valve regurgitation, your doctor may recommend that you take antibiotics before certain dental or medical procedures to prevent the heart infection endocarditis.
Once signs and symptoms of aortic valve regurgitation develop, you'll usually need surgery. However, if aortic valve regurgitation is weakening your heart, you may need surgery even if you feel well. While the heart is generally adept at counteracting deficiencies caused by a leaky aortic valve, the problem is that if the valve isn't fixed or replaced in time, the strength of your heart may decline so much that it's permanently weakened. You can avoid that by having surgery at the appropriate time.
The overall function of your heart and the amount of regurgitation help to determine when surgery is necessary. Surgical procedures include :
- Valve repair. Aortic valve repair is surgery to preserve the valve and to improve its function. Occasionally, surgeons can modify the original valve (valvuloplasty) to eliminate backward blood flow. You don't need long-term anticoagulation therapy after a valvuloplasty.
- Valve replacement. In many cases, the aortic valve has to be replaced to correct aortic valve regurgitation. In valve replacement surgery, the leaky aortic valve is replaced by an artificial (prosthetic) valve. The two types of artificial valves are mechanical and tissue. Mechanical valves are made from metal and are durable, but they carry the risk of blood clots forming on or near the valve. If you have a mechanical valve, you need to use anticoagulant medication for life to prevent blood clots from forming on the valve. Tissue valves generally come from a pig, cow or human-cadaver donor heart. These kinds of valves wear out over time, and you may need another operation to replace the valve. However, an advantage of the tissue valve is that you don't have to use long-term anticoagulation medication. Another type of tissue valve replacement, called an autograft is sometimes possible. An autograft valve replacement uses your own pulmonary valve — another heart valve — to replace your damaged aortic valve.
Aortic valve surgery usually involves open-heart surgery performed with general anesthesia. Your heart is exposed and connected to a heart-lung machine that assumes your breathing and blood circulation during the procedure. Your surgeon then repairs or replaces your leaky aortic valve.
Aortic valve regurgitation can be eliminated with surgery, and you can usually resume normal activities within a few months. The prognosis following surgery is generally good.
One possible way to prevent mitral valve regurgitation 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 if you have mitral valve regurgitation.
If you have mitral valve prolapse with mitral valve regurgitation, it's important to have your doctor regularly check the amount of regurgitation through regular physical examinations and follow-up echocardiograms when needed.