The mitral valve is a flap of tissue that sits in the left side of the heart, between the left atrium and the left ventricle. It keeps blood flowing in the forward direction, from the atrium into the ventricle, and stops blood from flowing backward.

The heart has four valves, and these ensure that blood flows in one direction only. One of these valves is the mitral valve.

These four valves sit between the different chambers of the heart. They also sit between the chambers and the main blood vessels that carry blood to and from the heart.

This article takes a look at the different valves of the heart, the mitral valve, and diseases of the mitral valve, including their symptoms, causes, diagnosis, and treatment options.

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The four valves of the heart are as follows:

  • Aortic valve: This is located between the left ventricle and the aorta.
  • Mitral valve: This is located between the left atrium and the left ventricle.
  • Pulmonary valve: This is located between the right ventricle and the pulmonary artery.
  • Tricuspid valve: This is located between the right atrium and right ventricle.

These valves all have a set of tissue flaps that are sometimes called leaflets. These flaps open and close to allow blood to pass through. The mitral valve has two leaflets, while the other three valves have three.

The mitral valve allows blood to pass from the left atrium into the left ventricle. It also prevents blood from passing from the left ventricle into the left atrium.

Mitral valve disease occurs when the mitral valve stops working correctly. There are a number of reasons that this valve may not work correctly.

Mitral valve disease can cause blood to flow backward into the left atrium (mitral regurgitation). It may also mean that not enough blood can pass through from the left atrium into the left ventricle (mitral valve stenosis).

Disrupted blood flow in the heart can lead to the heart not pumping enough oxygenated blood around the body. This can cause a person to feel fatigued or short of breath. Without treatment, it can cause serious, life threatening complications, including heart failure.

There are three main types of mitral valve disease. The sections below will look at each of these in more detail.

Mitral valve prolapse

Mitral valve prolapse (MVP) is a condition wherein two of the mitral valve’s flaps are too “floppy” and cannot close correctly. If the valves do not close smoothly, they can bulge upward into the left atrium.

This means that when the heart contracts to pump blood from the left atrium into the left ventricle, part of one or both of the mitral valve flaps collapse backward. This can allow blood to leak back through the valve and into the left atrium.

Healthcare professionals sometimes refer to MVP as click-murmur syndrome, Barlow’s syndrome, or floppy valve syndrome.

Mitral regurgitation

Mitral regurgitation (MR) is a condition wherein the mitral valves do not close correctly. Like MVP, MR can cause blood to leak back through the valve each time the left ventricle contracts.

MR affects more than 2% of the population, making it the most common valvular irregularity worldwide.

Without treatment, MR can cause a number of heart issues. These include an irregular heartbeat, high blood pressure, and heart failure.

Mitral valve stenosis

Mitral valve stenosis (MVS) occurs when the mitral valve opening becomes narrow or blocked. This happens when the mitral valve does not open as wide as it should. MVS then restricts blood flow from the left atrium to the left ventricle.

The restricted blood flow reduces the volume of blood that carries oxygen from the lungs. This can cause a person to feel tired and short of breath.

MVS can also cause the volume of blood in the left atrium to increase. This can cause pressure within the atrium to also increase.

Both of these outcomes can lead to the left atrium enlarging and possibly causing fluid to build up in the lungs.

The different types of mitral valve disease have their own causes. The sections below will look at these in more detail.


The most common cause of MVP is stretchy, floppy valve flaps.

This disease is often due to the degeneration of the integrity of the flap (myxomatous degeneration). Endocarditis, which is an infection of the inner lining of the heart, may also cause MVP.

A person may be born with a genetic risk of developing MVP. MVP may also develop due to other health problems, such as issues with the valve’s connective tissue.


MR occurs if the mitral valve cannot close correctly. This can result from the valves becoming too floppy (MVP) or due to the ring of muscle that surrounds the valve becoming too wide.

Damage to the mitral valve or the heart’s tissue cords or muscles can also cause MR. Endocarditis may also cause MR.

A person’s risk of developing MR increases with age.


There are a number of potential causes of MVS. These include:

Rheumatic fever is the most common cause of MVS.

Rheumatic fever is a condition that occurs as a complication of group A streptococcal infections, such as strep throat or scarlet fever. Rheumatic fever occurs when someone leaves an infection untreated or undertreated.

Rheumatic fever affects the heart and can cause inflammation. This can lead to a person developing:

  • Endocarditis: This affects the heart’s lining (endocardium).
  • Myocarditis: This affects the heart’s muscle (myocardium).
  • Pericarditis: This affects the membrane that surrounds the heart (pericardium).

If rheumatic fever damages the heart’s valves, it can lead to rheumatic heart disease (RHD). RHD can cause MVS. Healthcare professionals refer to RHD that results from MVS as rheumatic mitral stenosis.

The different types of mitral valve disease have a range of symptoms. The following sections will look at these symptoms in more detail.


It is fairly common for a person with MVP to have no symptoms at all. However, symptoms do sometimes arise. They can include:

  • a heart murmur
  • heart palpitations
  • chest discomfort
  • fatigue
  • shortness of breath


The symptoms of MR can differ depending on whether the condition is chronic or acute.

Chronic MR

Mild chronic MR may not cause any symptoms. However, if chronic MR becomes more severe, a person may begin to experience symptoms such as:

  • fatigue
  • shortness of breath during physical exertion
  • shortness of breath when lying flat
  • a reduced ability to exercise
  • heart palpitations
  • a noticeably and unpleasantly pronounced heartbeat
  • swelling in the abdomen, legs, and veins of the neck

A person with chronic MR may also experience chest pain, though this is less common.

Acute MR

Severe acute MR is a medical emergency. It can cause the following symptoms:

  • symptoms of shock, such as pale skin, loss of consciousness, rapid breathing, weakness, dizziness, and an altered mental state
  • severe shortness of breath
  • fever due to endocarditis
  • severe chest pain
  • abnormal heart rhythms that worsen the heart’s ability to pump

Sometimes, severe acute MR may cause heart failure. Heart failure can produce the following symptoms:

  • shortness of breath
  • coughing
  • congestion around the heart and lungs
  • swelling of the legs and feet (edema)


Some common symptoms of MVS include:

  • shortness of breath, particularly when exercising or lying down
  • fatigue
  • dizziness
  • chest pain

If MVS is more severe, a person may experience heart palpitations or arrhythmia.

The symptoms of MVS often develop gradually. They may appear or worsen when the body is dealing with extra stress, such as infections or pregnancy.

If a doctor suspects that a person has a mitral valve disease, they will listen to their heart with a stethoscope. During this process, they listen for heart murmurs, clicking sounds, palpitations, unusual sounds, or strange rhythms.

The doctor may also order an additional test to confirm their diagnosis and assess the severity of the condition. They may order one of the following:

  • Echocardiogram: This is an ultrasound of the heart that produces images of its structures for diagnosis.
  • Electrocardiogram: This test records the electrical activity of the heart.
  • X-ray: This test uses X-ray particles to produce images of the heart.

Treatment for mitral valve disease may not be necessary if the condition is not too severe. If this is the case, a doctor may suggest that a person makes lifestyle changes such as:

  • giving up smoking, if applicable
  • reducing their caffeine intake
  • reducing their alcohol intake
  • having regular checkups to monitor the condition

However, if someone requires treatment, the doctor may decide on one of a number of options. These include the following treatments.


Drugs cannot cure mitral heart disease. However, they can treat the symptoms or prevent it from worsening.

To do so, doctors may prescribe one of the following drugs:

  • diuretics, to reduce fluid accumulation in the lungs
  • blood thinners, to prevent clots from forming
  • antiarrhythmics, to treat abnormal heart rhythms
  • beta-blockers, to slow the heart rate


Another option for mitral valve disease is surgery. This is often the option that a doctor will choose if the condition is more severe.

During mitral valve surgery, a surgeon may repair the valve to allow it to function correctly. However, if the valve is in a particularly bad state, they may replace it with a biological or mechanical valve.


This is a non-surgical procedure that a doctor may choose to treat the narrowing of the mitral valve.

During this procedure, a healthcare professional inserts a long, thin tube called a catheter into blood vessels in the groin. At the end of the catheter, there is a deflated balloon. The healthcare professional then guides the catheter into the chambers of the heart.

They then create a small hole in the wall between the heart’s chambers, and this hole provides an opening to the left atrium.

The healthcare professional positions the balloon directly inside the narrowed valve before inflating it and deflating it several times to widen the opening of the valve. They then deflate the balloon and remove it from the person’s body.

The mitral valve sits in the left hand side of a person’s heart, between the left atrium and the left ventricle. It keeps blood moving in the right direction and prevents it from flowing backward into the left atrium.

Mitral valve disease occurs when the mitral valve does not work correctly. This can restrict blood flow through the heart and may cause blood to flow backward into the left atrium.

There are three different types of mitral valve disease: MVP, MR, and MVS.

A person with mitral valve disease may experience no symptoms. However, some common symptoms of mitral valve disease include shortness of breath, chest pain, and heart palpitations.

A person may not require treatment. However, a doctor may treat more severe cases with medication. They may treat even more severe cases with surgery or valvuloplasty.