Understanding Mitral Valve Regurgitation: Everything to Know

Medically reviewed by Anthony Pearson, MD

Mitral valve regurgitation is a type of heart valve disease in which the flaps of the mitral valve do not shut properly, allowing blood to leak backward (regurgitate) in the heart.

Because blood is not being pumped as effectively as it should, a person may experience heart palpitations, shortness of breath, swelling of the feet and ankles, and fluid in the lungs (pulmonary edema).

Mitral valve regurgitation can be definitively diagnosed with a noninvasive imaging study called an echocardiogram and other diagnostic tests and procedures. Milder cases may be treated with medications and lifestyle changes, while advanced cases may require surgery.

Here is what you need to know if you have been diagnosed with mitral valve regurgitation or have symptoms consistent with this most common form of heart valve disease.

How the Heart Works With Mitral Valve Regurgitation

The mitral valve, also known as the bicuspid valve, is one of the four valves that control the flow of blood in one direction through the heart. It lies between the two chambers of the heart called the left atrium and the left ventricle.

With each heartbeat, the mitral valve opens to transport oxygen-rich blood from the left atrium to the left ventricle where is it collected before being ejected out of the heart to the rest of the body.

Related: Anatomy of the Heart: Mapping Blood Flow

With mitral valve regurgitation—also known as mitral insufficiency, mitral incompetence, or simply mitral regurgitation (MR)—the two flaps of the valve (called leaflets) do not shut completely, allowing blood to flow backward from the left ventricle into the left atrium.

The leaky valve reduces the amount of oxygen-rich blood that is ejected from the heart, leading to symptoms that can become increasingly profound as the valve becomes less and less functional.

If the backflow is severe enough, the heart may enlarge over time in an effort to maintain adequate blood flow. This, in turn, places undue stress on the heart muscle and lungs, leading to potentially severe—and even life-threatening—complications if left untreated.

Related: Facts and Statistics About Heart Valve Disease

Types of Mitral Regurgitation

Mitral regurgitation can either be acute or chronic.

Acute MR is when an injury to the mitral valve causes it to suddenly become leaky. Because there is no time for the heart to compensate for the disruption of blood flow, symptoms can develop suddenly and severely. Acute MR is considered a medical emergency, typically requiring surgery to repair the damaged valve.

Chronic MR is when the loss of the mitral valve function is gradual and progressive. It can develop silently for many months or years, or develop overtly following a severe acute MR episode. The persistent leakage can cause structural (and often irreversible) changes to the heart as it struggles to keep up with the body's demand for oxygenated blood.

Over time, chronic MR can progress from the compensated phase where the heart can keep up with the body's demand, to the decompensated phase where it cannot.

Mitral regurgitation is also classified by how the valve damage occurred, as follows:

• Primary MR, sometimes called degenerative MR, is when the leaflets of the mitral valve or the connective tissues that maintain the position and tension of the mitral valve (called the chords) are damaged.

• Secondary MR, sometimes called functional or ischemic MR, is when changes to the left atrium or left ventricle place undue stress on the valve as the heart works harder to maintain circulation. In such cases, the mitral valve may still be functional even if blood is leaking backward.

What Causes Mitral Valve Regurgitation?

Mitral valve regurgitation is the most common heart valve disease affecting up to 10% of the general population. It is also the second most common indication for heart valve surgery behind aortic stenosis, a condition in which the valve regulating blood flow from the heart is narrowed.

How Common Is Mitral Regurgitation?

People of all sexes are equally affected by mitral regurgitation, with people over 75 years old being at greatest risk. The severity can vary, with some studies suggesting that 6% of adults over age 65 in the United States have moderate to severe MR.

The causes vary by whether the condition is primary or secondary.

Primary Mitral Regurgitation

The most common cause of primary MR—and the most common cause of MR overall—is mitral valve prolapse. This is when a leaflet of the mitral valve becomes abnormally thickened and floppy, causing it to slip back (prolapse) into the left atrium with each heartbeat.

Mitral valve prolapse can run in families as an inherited condition and is also linked to genetic disorders such as Marfan syndrome, Ehlers-Danlos syndrome, and Ebstein anomaly.

Other possible causes of primary MR include:

• Rheumatic heart disease: A complication of rheumatic fever in which the heart valves are permanently damaged

• Infective endocarditis: Inflammation of the heart chambers and valves caused when bacteria (and sometimes fungus) enter the bloodstream and travel to the heart
  

• Collagen vascular disease: A type of connective tissue disease in which autoimmune disorders like lupus target and damage collagen-containing tissues, including heart valves

• Certain medications: Including a class of diet pills called anorectics that work on the brain to suppress appetite

• Chest trauma: A less common cause in which a blunt force injury to the chest can rupture the chords.

Secondary Mitral Regurgitation

Secondary MR occurs when a disease causes the remodeling of tissues in the left ventricle or atrium. This can often lead to the widening (dilation) of either of the two chambers, causing muscles controlling the mitral valve to become stretched, weakened, or displaced.

At other times, the ventricle or atrium might experience hypertrophy, in which tissues become stiff and thicker.

Diseases associated with secondary MR include:

• Coronary artery disease: Damage to the left ventricle from blocked arteries that results in enlargement of the left ventricle cavity, which stretches the mitral leaflets apart

• Heart failure: A progressive condition in which the heart becomes less able to pump sufficient amounts of blood to service the body's needs

• Myocardial infarction: Also known as a heart attack

• Atrial fibrillation: A condition in which uncoordinated electrical impulses in the left atrium cause abnormal and irregular heartbeats

Related: What Is Tricuspid Regurgitation?

Complications of Mitral Valve Regurgitation

Complications of MR occur when the heart has to work harder to compensate for the leaky valve. In some cases, it can lead to the same conditions that instigate MR. The risk increases with the stage of the disease.

Possible complications of mitral regurgitation include:

• Heart failure: One of the most common complications affecting 20% of people with mitral valve prolapse

• Atrial fibrillation: A condition associated with a twofold increased risk of cardiac death or heart failure in people with MR

• Cardiomegaly: Enlargement of the left ventricle and left atrium

• Pulmonary artery hypertension: A type of high blood pressure that affects the arteries in the lungs and right side of the heart

• Pulmonary edema: The buildup of fluid in one or both lungs, most typically associated with the progression of heart failure

Mitral Valve Regurgitation Symptoms

The symptoms of MR can vary by the stage of the disease.

When MR is compensated, it is not uncommon for there to be no symptoms at all. It is only when the disease is decompensated and the heart has been significantly compromised—typically over the course of years or decades—that nonspecific symptoms (those that could be due to a number of causes) can suddenly become overt and severe.

Symptoms of mitral regurgitation include:

• Persistent fatigue

• Heart palpitations

• Shortness of breath with activity (dyspnea with exertion)

• Shortness of breath when lying down (orthopnea)

• Shortness of breath that awakens you from sleep (paroxysmal nocturnal dyspnea)

• Reduced tolerance for exercise

• Swelling of the lower legs, ankles, and feet (peripheral edema)

How Is Mitral Valve Regurgitation Diagnosed?

The diagnosis of MR can be challenging because healthcare providers need to actively look for it. There may be telltale signs, but these can be easily overlooked if a person is otherwise healthy and asymptomatic (symptom-free).

One of the earliest clues of mitral regurgitation is a heart murmur, sometimes spotted incidentally during a routine physical exam.

Mitral Regurgitation and Heart Murmurs

With mitral regurgitation, a whooshing sound can be heard through a stethoscope whenever the heart muscle contracts. The murmur is caused by the sound of blood gushing backward through the mitral valve.

Even so, the murmur can be missed if the disease is mild. It is also best heard when the person is lying on their left side and may be less audible if they are seated upright.

Tests

If MR is suspected, the healthcare provider may order imaging studies and other tests and procedures to confirm the diagnosis. These include:

• Chest X-ray: A plain-film study sometimes used to detect dilation or hypertrophy of the left ventricle or atrium

• Transthoracic echocardiogram (TTE): A real-time imaging study that uses high-frequency soundwaves (ultrasound) to assess the size of the heart's chambers, the movement of the heart valves and walls, and the volume of blood pumped from the heart

• Electrocardiogram (ECG): A noninvasive test that measures the electrical activity of the heart which may help spot abnormalities in heartbeats

• Cardiac magnetic resonance imaging (MRI): An imaging study that uses powerful magnetic and radio waves to create highly detailed images of the heart, including the valves and chambers

• Cardiac catheterization: A procedure in which a narrow tube is inserted into a vein and threaded into the heart to assess the function of the valves and the pressure of blood flow moving through the heart

Staging

Mitral regurgitation is broadly characterized by how functional (compensated) or nonfunctional (decompensated) the condition is. Beyond this broad definition, heart specialists known as cardiologists will also stage the disease to help guide the appropriate course of treatment based on several factors, including:

• Your symptoms

• Changes in the anatomy of your mitral valve

• The severity of mitral valve dysfunction

The stages of MR also direct how often you need to undergo TTE monitoring. Routine echocardiograms can tell whether there is any progression of the disease so that adjustments can be made to your treatment plan.

The American College of Cardiology and the American Heart Association (ACC/AHA) define the four stages of mitral regurgitation as follows:

Related: How Mitral Regurgitation Is Staged

How Is Mitral Valve Regurgitation Treated?

The treatment of mitral regurgitation depends largely on whether or not it is causing symptoms. The treatment may involve routine TTE monitoring with or without medications or surgery to avoid heart failure and other disease complications.

Medications

Generally speaking, a person with no symptoms does not need treatment and is instead routinely monitored as directed by the stage of their disease.

Even so, some healthcare providers will prescribe drugs that are thought by some to slow disease progression. These include:

• Angiotensin converting enzyme (ACE) inhibitors: Used to reduce blood pressure and the workload of the heart while pumping blood

• Beta-blockers: Used to reduce the excess stress on the heart muscle, allowing the heart to do more work with less energy

• Diuretics ("water pills"): Used to reduce blood pressure and improve blood flow by drawing excess fluid from blood plasma and removing it from the body in urine
  

Do Medications Help?

The evidence supporting the use of drugs to slow MR progression remains uncertain. The ACC/AHA currently do not include them in their treatment guidelines with the exception of anticoagulants (blood thinners) used to prevent blood clots in people with atrial fibrillation.

Mitral Valve Regurgitation Surgery

People with symptoms of severe mitral valve regurgitation are typically advised to undergo surgery to prevent heart failure. Even those who are asymptomatic may be referred for surgery if the expulsion of blood from the left ventricle (called the ejection fraction) is significantly low.

Surgery can take several forms, including:

• Mitral valve repair: This can be done as an open surgery or minimally invasive robotic or laparoscopic surgery. The procedure may involve ring annuloplasty that tightens the valve with a metal or cloth ring, or leaflet repair that trims and reshapes the leaflets so that they shut tightly.

• Transcatheter mitral valve replacement (TMVT): This surgery accesses your heart through a vein in your groin. TMVT can either replace a damaged valve with a prosthetic (artificial) valve or replace a damaged prosthetic valve with a new prosthetic valve.

• Mitral valve clip: The procedure, also known as transcatheter edge-to-edge repair (TEER), accesses the valve leaflets via a vein in your groin. A proprietary device (called a MitraClip or Pascal) is then clipped onto the leaflets to pull them into the correct alignment.

• Surgical mitral valve replacement: Open heart surgery is performed utilizing either a tissue or mechanical valve replacement.

The ACC and AHA generally recommend mitral valve repair over mitral valve replacement due to the lower risk of short- and long-term complications.

Related: How Heart Valve Disease Is Treated

What’s the Outlook for Someone With Mitral Valve Regurgitation?

Mitral valve regurgitation is associated with an increased risk of illness and death, particularly if left untreated.

Studies suggest that the two-year survival rate for severe primary MR is 92% (meaning that 92% of people will live for at least two years following their diagnosis). The six-year survival rate is far less favorable, falling to 65%.

Most studies show that people with severe primary MR will almost inevitably need surgery or die within 10 years. The risk of death increases substantially with age.

However, if treated, the prognosis for primary MR is greatly improved. A 2020 study published in the Annals of Thoracic Surgery reported the surgical repair of primary MR restores life expectancy to that of the general population regardless of the person's age.

Lifestyle and Home Remedies for Mitral Valve Regurgitation

If you have been diagnosed with MR, it is important to remember that the disease has no single pathway. Some people may never develop symptoms or severe disease. Others may experience rapid deterioration of mitral valve function, both for factors they cannot control (like genetics) and some that they can (like high blood pressure and coronary artery disease).

To this end, it is important to make healthy lifestyle choices if diagnosed with any stage of mitral valve regurgitation, including:

• Quitting cigarettes: Smoking tobacco increases blood pressure by causing the constriction (narrowing) of blood vessels. Ask your healthcare provider about smoking cessation aids, many of which are covered under the Affordable Care Act.

• Exercising regularly: This includes regular aerobics training to reduce blood pressure and prevent atherosclerosis. Before starting, speak with your healthcare provider to ensure that the exercise level is appropriate and doesn't place undue stress on your heart.

• Maintaining a healthy weight: Lose weight if you need to, albeit without diet pills and stimulants that can cause rapid heartbeats and place undue stress on the heart.

• Practicing good dental hygiene: Diseased gums allow bacteria and other germs to enter the bloodstream, potentially causing infective endocarditis. Brushing and flossing regularly significantly decreases the risk.

• Managing your other health conditions; This includes chronic diseases like high blood pressure, diabetes, thyroid disease, chronic obstructive pulmonary disease (COPD), and heart disease.

• Getting vaccinated: This includes the COVID-19 vaccine, annual flu shot, and the pneumococcal vaccine, which can prevent heart complications of pneumococcal pneumonia (such as pericarditis).

Related: Benefits of Exercise With Mitral Valve Prolapse

When to See a Healthcare Provider

Arguably, the biggest concern related to mitral valve regurgitation is the risk of decompensation and the development of heart failure. As obvious as this may sound, it has become a growing public health concern as only a small proportion of people with advanced MR undergo mitral valve repair.

A 2018 study published in the Lancet reported that a mere 15% of people qualified for mitral valve repair pursued treatment.

To this end, it is important to see a healthcare provider if you experience any of the signs and symptoms of heart failure, including:

• Persistent fatigue and weakness

• Rapid, unexplained weight gain

• Swelling of the lower extremities

• Shortness of breath with activity or when lying down

• Rapid or irregular heartbeats
  

• A persistent cough or a cough that brings up white or pinkish mucus
  

• Abdominal swelling

• Wheezing

Related: How to Know If You Have Heart Failure

Summary

Mitral regurgitation (MR) is the backflow of blood from the left ventricle to the left atrium caused by damage to the mitral valve (primary MR) or by abnormal changes to the left atrium or left ventricle (secondary MR).

Symptoms include fatigue, shortness of breath, heart palpitations, and swelling of the lower legs, ankles, or feet. Many people with early-stage MR have no symptoms. MR can be diagnosed with imaging studies like transthoracic echocardiogram (TTE) and procedures like electrocardiogram (EEG).

Asymptomatic MR is usually not treated but is instead regularly monitored with TTE screening. Surgery is recommended for people with symptomatic MR, which can dramatically increase survival times and life expectancy.

Read the original article on Verywell Health.