Please read the Disclaimer at the end of this page.
MITRAL REGURGITATION OVERVIEW — Mitral regurgitation (MR), which is also known as mitral insufficiency, is a common heart valve disorder. When MR is present, blood leaks backwards through the mitral valve when the heart contracts. This reduces the amount of blood that is pumped out to the body.
This topic review discusses the causes, signs and symptoms, diagnosis, and treatment options for people with mitral regurgitation.
HEART FUNCTION
Normal heart — The heart is a pump that contains four chambers: the right atrium, right ventricle, left atrium, and left ventricle (figure 1). Blood returning to the heart flows into the right atrium, and then the right ventricle. Blood is pumped out of the right ventricle into the lungs, where oxygen is added. Blood then returns to the left heart chambers through the left atrium; it then flows into the left ventricle, which pumps the blood to the rest of the body through the aorta.
The heart normally contracts and relaxes in a rhythmic fashion. This action causes changes in pressure within the heart that allow the heart to fill with blood (during relaxation) and to pump blood forward to the body (during contraction).
There are four valves in the heart:
●Two valves separate the upper chambers (the atria) and the lower chambers (the ventricles) (figure 1). On the right, the tricuspid valve separates the right atrium from the right ventricle. On the left, the mitral valve separates the left atrium from the left ventricle.
●Two valves separate the heart from the major blood vessels: One is between the right ventricle and the lungs (pulmonic valve), and other is between the left ventricle and the aorta (aortic valve).
These valves consist of flaps called leaflets or cusps that open and close to help ensure the continued pulsatile forward flow of blood through the heart.
Mitral regurgitation — With mitral regurgitation (MR), blood leaks backwards through the mitral valve and into the left atrium when the heart contracts. This means that less blood is pumped out of the heart to the body. If the amount of MR is small and does not progress, the backward leak has no significant consequences.
If significant (moderate to severe) MR is present, the left ventricle must work harder to keep up with the body's demands for oxygenated blood. Over time, the heart muscle (the myocardium) and circulatory system undergo a series of changes to maintain this increased demand. These changes generally occur in phases over many years, even decades, depending upon the amount of blood that is leaking backward and how the heart responds to MR. The cause of MR also influences how soon the heart begins to fail.
Compensated phase — The major change during this phase is enlargement of the left ventricle. This is known as the compensated phase, which does not usually cause symptoms, the heart rhythm is usually normal, and if the leak is not severe, surgical treatment is generally not required.
Transitional phase — As MR progresses, the heart muscle (myocardium) begins to weaken, and the ventricle can no longer compensate for the regurgitation. This phase is called the transitional phase. The reason that you might progress from the compensated to the transitional phase is not completely clear, although changes in heart structure or heart pumping function may occur as progressively greater volumes of blood are leaking backward.
You may experience fatigue, with a decreased ability to exercise or be active, or you may feel short of breath in the transitional phase. However, some people have no symptoms. Surgical treatment is usually recommended when you enter the transitional phase. (See 'Surgical treatment' below.)
Decompensated phase — As the left ventricle enlarges and functions less efficiently, the left atrium progressively enlarges, abnormal heart rhythms occur, and the blood pressure in the pulmonary arteries (the blood vessels from the heart to the lungs) increases; this is called pulmonary hypertension. Over time, as heart failure develops, these changes become irreversible. (See "Patient education: Heart failure (Beyond the Basics)".)
MITRAL REGURGITATION CAUSES — A trivial amount of mitral regurgitation (MR) is present in up to 70 percent of adults. Significant (moderate to severe) MR is much less common. When significant MR does happen, it can be a result of an abnormality in a heart valve or another cardiac disease, including the following:
●Mitral valve prolapse – Mitral valve prolapse occurs when the mitral valve leaflet tissue is deformed and elongated so that the leaflets do not come together normally. This abnormal valve motion may allow blood to leak backwards from the left ventricle into the left atrium. Although most people with mitral valve prolapse have only trace or mild MR, some develop significant MR.
●Infective endocarditis – Infective endocarditis is an infection of the heart valves caused by bacteria, fungi, or other organisms that invade the bloodstream. As the microorganisms adhere to the valves and grow, abnormal structures (known as vegetations) develop on the heart valves. The vegetation can prevent the mitral valve from closing normally, allowing blood to regurgitate. A heart valve that is already abnormal is more likely to develop endocarditis compared with a valve that is normal.
●Rheumatic fever – Rheumatic fever is a body-wide illness that occurs when the bacterium that causes Strep throat (group A Streptococcus) is not treated. Rheumatic fever causes inflammation of the valves of the heart, as well as other complications. Rheumatic fever is now uncommon in developed countries, although it still occurs commonly in resource-limited countries.
●Congenital heart abnormality – Children who are born with certain types of heart abnormalities can develop MR.
●Other types of heart disease – MR can develop as a result of other types of heart diseases, such as after a heart attack or other cause of heart muscle injury.
●Trauma – Chest trauma can rarely cause breakage of the chords that hold the mitral leaflets in their normal position. Untethered leaflets swing widely, allowing valve leakage.
MITRAL REGURGITATION SIGNS AND SYMPTOMS — Most people with mitral regurgitation (MR) have no symptoms. People with mild to moderate MR may never develop symptoms or serious complications.
Even in people with severe MR, there may be no signs or symptoms until the left ventricle fails, an abnormal heart rhythm develops (atrial fibrillation), or pulmonary hypertension occurs. Pulmonary hypertension occurs when the blood pressure in the pulmonary artery is increased. This increases the workload of the right side of the heart, making it difficult to provide an adequate amount of oxygenated blood to the body.
People with severe MR and left ventricular enlargement may eventually develop signs and symptoms of heart failure, which include weakness and fatigue, shortness of breath with exertion and/or at rest, or edema (abnormal fluid collection in the lower legs or abdomen). (See "Patient education: Heart failure (Beyond the Basics)".)
MITRAL REGURGITATION DIAGNOSIS — You may be diagnosed with mitral regurgitation (MR) after your health care provider listens to your heart with a stethoscope and hears a heart murmur. The murmur is caused by the sound of turbulent blood flowing backwards through the mitral valve.
A heart murmur may occur as a result of one or more conditions; to determine the cause of the murmur, one or more diagnostic tests may be recommended.
Electrocardiogram (ECG) — An ECG provides a picture of the electrical activity that causes the heart to beat. An ECG may detect rhythm disturbances or evidence of coronary heart disease or other conditions that can cause MR. It can also show evidence of other associated cardiac abnormalities.
Chest x-ray — A chest x-ray shows the size and shape of the heart and the large blood vessels in the chest. It also can identify fluid accumulation in the lungs. Many people with significant MR have an enlarged heart.
Echocardiogram — An echocardiogram uses ultrasound (high-frequency sound waves) to assess the size of the heart's chambers, the movement of the heart valves, and the motion of the heart wall. It can also measure the cardiac output (the volume of blood pumped in one minute) and some of the pressures within the heart.
In most cases, the echocardiogram is done by pressing a smooth probe against the skin of the chest or abdomen. Gel is applied to the chest to help the wand glide against the skin and allow the sound waves to travel through the chest more easily. This type of echocardiogram is called a transthoracic echocardiogram.
If the images of the heart are not clear with transthoracic echocardiography, a transesophageal echocardiogram (TEE) may be recommended. With TEE, you are given sedative medication and the probe is inserted into your mouth and passed down the esophagus. This allows the physician to have a closer and clear view of your heart valves and other structures.
LIVING WITH SIGNIFICANT MITRAL REGURGITATION
Monitoring over time — People with mitral regurgitation (MR) should have periodic monitoring to determine if and when treatment is needed. The frequency of repeat echocardiogram depends upon several factors, including the severity of the MR, the size and function of the left ventricle, and the presence of symptoms.
●People with mild MR and normal left ventricular size and function should have an echocardiogram (an imaging test of the heart) every three to five years.
●People with moderate MR should have an echocardiogram every one to two years.
●People with severe MR are usually seen every 6 to 12 months or sooner if symptoms develop or if the left ventricle size is increasing.
Physical exercise — The 2015 American College of Cardiology/American Heart Association guidelines concluded that no exercise restrictions are needed for people who have the following:
●No symptoms of MR
●A normal heart rhythm
●Normal size left ventricle and left atrium
●Normal pulmonary artery pressure
Your health care provider can help to determine if you should exercise or participate in sports if you have one or more abnormalities of the above (eg, left ventricular enlargement). Athletes with MR should receive a yearly physical examination, echocardiogram, and exercise testing to determine what level of activity is safe.
Mitral regurgitation and pregnancy — Women with chronic mild to moderate MR usually have no increased risks as a result of pregnancy. In contrast, women with severe MR, especially if they have symptoms or other complications of MR, can be at risk of developing complications during pregnancy. Women with MR should talk to their cardiologist about the risks and benefits of pregnancy and the possibility of having valve repair or replacement surgery before trying to become pregnant. Valve repair or replacement surgery is not recommended during pregnancy except in emergency situations.
Presence of atrial fibrillation — People with chronic MR may develop an abnormal heart rhythm called atrial fibrillation (AF). In AF, rapid, chaotic electrical impulses cause the heart to beat irregularly rather than in a coordinated fashion. As a result, the patient may sense an irregular pulse and complain of palpitation. AF can reduce the amount of blood being pumped out to the body; this is of particular concern in people with MR because the heart already has a decreased ability to pump blood out. In addition, AF increases the risk of experiencing a stroke.
People with MR who develop AF are usually treated with a medication to prevent blood clots and may be given a treatment to normalize the heart rhythm. This is discussed in a separate article. (See "Patient education: Atrial fibrillation (Beyond the Basics)".)
After the initial treatment of AF, people with MR are often encouraged to have surgical valve repair or replacement before the left atrium enlarges substantially. Delaying surgical repair may make it more difficult to reverse AF to a normal heart rhythm. In people with MR, chronic AF significantly increases the chance of developing a blood clot (thrombus) that can break off (embolus) and lodge in an artery in the brain (causing a stroke) or somewhere else in the body. (See "Patient education: Stroke symptoms and diagnosis (Beyond the Basics)" and "Patient education: Pulmonary embolism (Beyond the Basics)".)
MITRAL REGURGITATION TREATMENT — Treatment of mitral regurgitation (MR) depends upon the cause of the MR and the presence and severity of symptoms . Many people with mild or moderate MR do not require any specific treatment, but should be monitored. (See 'Monitoring over time' above.)
For people who do need treatment, options include:
●Surgery to repair or replace the mitral valve
●A procedure to repair the mitral valve through a thin tube (catheter)
●Medicine or surgery to correct heart rhythm problems that often affect people with mitral valve disease
●Medicines that make it easier for the heart to do its job
Surgical treatment — Surgery is required for some people with severe MR (as identified by echocardiography). (See 'Echocardiogram' above.)
Surgical treatment may include either repair of your own mitral valve or replacement of the valve. The choice of procedure depends, at least in part, upon the cause of the MR, the anatomy of your mitral valve, and the performance of the left ventricle.
The procedure — Valve repair or replacement surgery is done in an operating room after you are given general anesthesia. With the traditional approach, the surgeon makes an incision in the breastbone (sternum), called a median sternotomy, to open the chest and gain access to the heart. Other approaches, which do not involve cutting the sternum, are available, although there are fewer data regarding the safety and efficacy of these newer techniques.
To repair or replace the valve, the heart must be stopped temporarily. While the heart is stopped, a heart-lung machine (cardiopulmonary bypass machine) functions like the heart and lungs, circulating blood and providing oxygen to the body. Fluids, nutrients, and medications may be added to the blood while it passes through the cardiopulmonary bypass machine. The procedure generally lasts between two and four hours.
Valve repair — During valve repair, the surgeon will reshape the valve to prevent or reduce the backwards flow of blood. People who have valve repair do not require lifelong treatment with an anticoagulant (blood thinner).
Valve replacement — If valve replacement is necessary, the replacement valve may be mechanical (made from metal) or bioprosthetic (made from biologic materials such as a pig valve). Mechanical valves have the disadvantage of requiring lifelong treatment with a medication to prevent blood clots (warfarin [brand name: Jantoven]), while bioprosthetic valves (which generally do not require warfarin) have the disadvantage of potentially wearing out and requiring replacement earlier, particularly in people under age 60. People who are in atrial fibrillation (AF) generally need lifelong anticoagulation, regardless of which valve type is used.
When deciding between a mechanical and bioprosthetic heart valve, it is important for you and your physician to consider the risks of warfarin therapy compared with the potential need for a repeat valve replacement. The use of warfarin is discussed in detail in a separate article. (See "Patient education: Warfarin (Beyond the Basics)".)
In general, experts use guidelines like the following:
●A mechanical valve is suggested for patients <70 years of age who do not have a contraindication to anticoagulation.
●A bioprosthetic valve is suggested for patients 70 years old or older.
●A bioprosthetic valve is recommended in patients of any age for whom anticoagulant therapy is contraindicated, cannot be managed appropriately, or is not desired by the patient.
Additional procedures — When people with MR and AF have valve surgery, they may have one or more additional procedures at the same time:
●A procedure called "left atrial appendage closure" (also known as left atrial appendage occlusion or ligation) is often done to reduce the risk of stroke (brain damage from a blood clot in an artery going to the brain).
●A procedure called the "maze procedure" is often done to reduce the likelihood of long-term AF. During the procedure, several small incisions are made in the left atria to interrupt the electrical pathways that allow atrial fibrillation to occur. The decision to perform a maze procedure is based upon the person's age and other factors because it does increase the length of the operation.
Recovery from surgery — Most patients are able to leave the hospital within five to six days after surgery. Some people are able to be discharged after four days, while others may require a longer stay, especially if complications (eg, bleeding, infection) develop.
Depending upon your occupation, you will probably be able to return to work within two months after discharge from the hospital. Some people are able to return to work after one month, while others may require up to three months to feel well enough to return.
You will generally see your surgeon approximately one week after surgery and your cardiologist one to two weeks later. A postoperative echocardiogram (and sometimes an electrocardiogram) is usually performed at that time.
Transcatheter mitral valve repair — Transcatheter mitral valve repair is a way of repairing a mitral valve using a clip that is guided into place using a catheter (thin tube). Transcatheter mitral valve repair is an option for some people with more than moderate MR.
Treatment with medications — One or more medications may be recommended for some people with MR to relieve the signs and symptoms of heart failure, reduce the workload of the heart, or prevent complications such as blood clots or infections. Treatment of heart failure is discussed in detail in a separate topic review. (See "Patient education: Heart failure (Beyond the Basics)".)
Anticoagulants — Anticoagulants such as warfarin are used to prevent blood clots. Lifelong treatment with warfarin (brand name: Jantoven) is recommended for certain people with chronic MR, including those with AF or a mechanical heart valve. (See "Patient education: Warfarin (Beyond the Basics)".)
Preventive antibiotic treatments — Infective endocarditis is a bacterial infection that causes the heart valves to become inflamed. Most people with MR who have not undergone heart valve surgery do not require preventive antibiotic treatment before dental and surgical procedures.
In contrast, people who have a mechanical or bioprosthetic replacement mitral valve or who have prosthetic material used to repair the mitral valve should have antibiotic treatment before dental, oral, or upper respiratory tract procedures to reduce the risk of developing infective endocarditis. This is discussed in detail in a separate article. (See "Patient education: Antibiotics to prevent heart valve infections (Beyond the Basics)".)
WHERE TO GET MORE INFORMATION — Your health care provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient education: Mitral regurgitation (The Basics)
Patient education: Mitral valve prolapse (The Basics)
Patient education: What can go wrong after a heart attack? (The Basics)
Patient education: Heart murmurs (The Basics)
Patient education: Prosthetic valves (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient education: Heart failure (Beyond the Basics)
Patient education: Atrial fibrillation (Beyond the Basics)
Patient education: Stroke symptoms and diagnosis (Beyond the Basics)
Patient education: Pulmonary embolism (Beyond the Basics)
Patient education: Warfarin (Beyond the Basics)
Patient education: Antibiotics to prevent heart valve infections (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Arrhythmic complications of mitral valve prolapse
Echocardiographic evaluation of the mitral valve
Clinical manifestations and diagnosis of chronic mitral regurgitation
Indications for intervention for chronic severe primary mitral regurgitation
Natural history of chronic mitral regurgitation caused by mitral valve prolapse and flail mitral leaflet
Management of chronic primary mitral regurgitation
Pathophysiology and natural history of chronic mitral regurgitation
Acute mitral regurgitation in adults
Transesophageal echocardiography in the evaluation of mitral valve disease
Valvular heart disease in older adults
The following organizations also provide reliable health information.
●National Library of Medicine
(www.nlm.nih.gov/medlineplus/ency/article/000176.htm)
●National Heart, Lung, and Blood Institute
●American Heart Association
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges William H Gaasch, MD (deceased), who contributed to an earlier version of this topic review.
