What is the mitral valve?

The mitral valve is also known as the bicuspid valve. This is one of the heart’s four valves that help prevent blood from flowing backward as it moves through the heart.

Read on to learn more about the mitral valve, including its location and anatomy.

Where is the mitral valve?

The mitral valve is located in the left side of the heart, between the left atrium and left ventricle. Oxygen-rich blood flows into the left atrium from the pulmonary veins. When the left atrium fills with blood, the mitral valve opens to allow blood to flow to the left ventricle.

It then closes to prevent blood from flowing back into the left atrium. All of this happens in a matter of seconds as the heart beats.

What do the mitral valve’s different parts do?

The mitral valve has several unique features that allow it to keep blood moving through your heart.


The mitral valve has two leaflets. These are projections that open and close.

One of the leaflets is called the anterior leaflet. This is a semicircular structure that attaches to two-fifths of the mitral valve’s area.

The other is called the posterior leaflet. It attaches to the remaining three-fifths of the valve. Doctors usually divide the posterior leaflet into three scallops called P1, P2, and P3.


The commissures of the mitral valve are the areas where the anterior and posterior leaflets meet.

Chordae tendinae

The chordae tendinae are fan-shaped connective structures that connect the leaflets to papillary muscles in the heart. They help maintain the connection between the left ventricle and the mitral valve so it can open and close with less tension.

Zone of coaptation

The zone of coaptation is a rough area on the top side of the valve’s surface. It’s where the chordae tendinae attach the mitral valve to the papillary muscles.

This area makes up a small portion of the mitral valve, but any irregularities in it can prevent the valve from functioning properly.

Mitral annulus

The mitral annulus is a ring that’s attached to the mitral valve. It connects the tissue to the left atrium and ventricle.

Similarly to the leaflets, the mitral annulus has both anterior and posterior portions.

Mitral valve diagram

Explore the interactive 3-D diagram below to learn more about the mitral valve.

What conditions affect the mitral valve?

Several conditions can lead to mitral valve disease. This refers to any type of dysfunction of the mitral valve.

Mitral valve prolapse

Mitral valve prolapse is the most common reason for mitral valve repair in the United States. This condition occurs when the valve doesn’t completely close because it’s loose.

Mitral valve prolapse doesn’t always cause symptoms. But in some people, it can cause mitral valve regurgitation, which can cause some symptoms.

Mitral valve regurgitation

Mitral valve regurgitation refers to extra blood flowing backward through the mitral valve and into the left atrium. This makes the heart work harder to move blood, causing an enlarged heart.

Mitral valve prolapse can cause mitral valve regurgitation. A variety of other conditions, including a heart attack or rheumatic fever, can also cause it.

This condition can cause a range of symptoms, including:

  • heart palpitations
  • irregular heartbeat
  • shortness of breath
  • swelling in legs or feet
  • chronic cough

Mitral valve stenosis

Mitral valve stenosis occurs when the mitral valve doesn’t open efficiently. This results in less blood going through the valve. In response, the heart has to squeeze harder and faster to move enough blood through the heart.

Symptoms of mitral valve stenosis include:

  • dizziness
  • swollen feet
  • shortness of breath
  • coughing up blood
  • chest pain

Is mitral valve disease preventable?

You can protect against mitral valve disease by making a few lifestyle adjustments:

  • Reduce your sodium intake by avoiding processed foods and limiting the amount of salt you use when cooking.
  • Limit or avoid alcohol.
  • Get at least 30 minutes of exercise more days of the week than not.
  • Maintain a healthy weight to reduce the workload on your heart.