The four valves of the heart allow blood into the heart and prevent it from flowing in the wrong direction. The valves open or close each time the heart beats. This ensures the body always has a sufficient blood supply, and the blood is moving as it should.

The four heart valves are:

  • the mitral valve
  • the aortic valve
  • the tricuspid valve
  • the pulmonic valve

Doctors call the mitral and tricuspid valves the atrioventricular valves, and the aortic and pulmonic valves the semilunar valves.

Keep reading to learn more about each of the four heart valves.

In a healthy heart, blood flows in only one direction. The valves close off parts of the heart, preventing the blood from flowing backward.

  1. The process begins when oxygen-depleted blood (from the arms, legs, body, and head) enters the right atrium. This is the upper chamber on the right side of the heart and is the storage chamber.
  2. The blood then flows through the tricuspid valve into the right ventricle, which is the lower right pumping chamber.
  3. The ventricle pumps this blood through the pulmonary valve to the pulmonary artery, where it enters the lungs for oxygenation.
  4. Oxygen-rich blood re-enters the heart through the left atrium, which is the upper left chamber.
  5. It then flows through the mitral valve to the left ventricle, or the left pumping chamber.
  6. Finally, it moves through the aortic valve and then through the aorta to the rest of the body.

The four heart valves all have a role in ensuring that the blood can only flow in one direction. The four heart valves are:

Tricuspid valve

The tricuspid valve is named because it has three flaps called cusps, or leaflets. Blood flows through this valve after leaving the right atrium. After passing through the tricuspid valve, blood flows to the right ventricle.

People with a rare disorder called tricuspid atresia are born without a tricuspid valve. Tricuspid atresia means that blood cannot flow from the right atrium to the right ventricle.

Tricuspid regurgitation means that this valve cannot fully close, while tricuspid stenosis causes the valve to thicken, narrowing its opening.

Pulmonic valve

The pulmonic, or pulmonary valve, is the next valve that deoxygenated blood flows through. It closes off the right ventricle and opens to allow the blood to flow to the lungs.

Stenosis of the pulmonary valve causes this valve to thicken with time, narrowing its opening and making blood flow more slowly.

Regurgitation prevents the valve from closing fully, causing blood to flow backward into the right ventricle.

A rare pulmonic valve disorder called pulmonary atresia means that a person is born without this valve.

Mitral valve

The mitral valve closes off the left atrium, allowing oxygenated blood from the lungs to flow through to the left ventricle.

One of the most common types of mitral valve issues is mitral valve prolapse (MVP). This causes the leaflets of the mitral valve to fit together poorly or buckle backward, allowing blood to flow back to the left atrium.

Some connective tissue disorders may also damage the mitral valve, causing MVP.

Mitral valve prolapse can result in mitral valve regurgitation, which causes blood to flow backward. A heart attack or enlargement of the heart can cause the leaflets of the valve to spread apart, leading to mitral regurgitation.

Mitral valve stenosis hardens and thickens the walls of the mitral valve, narrowing the opening and causing blood to flow more slowly.

Aortic valve

The aortic valve is the final valve that oxygen-rich blood passes through before exiting the heart and coursing through the rest of the body. The valve prevents blood from flowing back to the left ventricle.

Aortic regurgitation, or aortic insufficiency, means that the aortic valve does not fully close, allowing blood to flow backward.

Aortic stenosis means that the aortic valve thickens or hardens, narrowing the path through which blood can flow. This delays or prevents adequate blood flow to the rest of the body.

Heart valve problems fall into two broad categories:

Regurgitation

When the valve fails to close fully, the blood regurgitates backward. This can happen when the cardiac chambers enlarge. It may also occur when the two leaflets of the valve do not close fully, such as with mitral valve prolapse.

When the problem is with the valve, doctors call it primary valvular. When the problem occurs in the heart’s chambers, such as the ventricles, doctors call it secondary valvular.

Stenosis

Stenosis happens when the tissue of the valve thickens, limiting blood flow. This often occurs when calcium and other deposits accumulate on the leaflets of the valve.

The heart thickens with time, but the blood supply is not enough to sustain the heart. This can cause severe illness and even death.

Untreated heart valve problems may cause shortness of breath, especially on exertion. They are also a risk for heart failure, stroke, and sudden death.

A person may be born with a valve problem. Valve problems can also develop due to aging or damage from chronic illnesses, such as diabetes or other diseases, such as carcinoid disease.

Some unhealthful lifestyle choices, such as smoking, may also increase the risk of heart issues, including valve problems.

The symptoms of a heart valve problem are similar to symptoms of other heart diseases, and include:

  • dizziness or fainting
  • shortness of breath
  • heart palpitations, which happen when the heart skips a beat
  • chest pain
  • unexplained swelling in the body

In the case of a valve that does not close all the way, a doctor may recommend surgery to repair the leaflets of the valve. Doctors prefer surgery for mitral valve or tricuspid valve regurgitation.

When surgery fails to repair the valve, a surgeon may perform a heart valve replacement procedure. An artificial valve functions in the same way as a natural valve.

Surgery can be complicated, but sometimes, a surgeon can undertake this with a minimally invasive procedure.

A person may also need to treat any underlying conditions. This could include taking diabetes medications or changing the medication they take for some conditions, such as lupus.

Making lifestyle changes can reduce the risk of further valve damage and other heart health problems. Talk to a doctor or healthcare provider about quitting smoking, exercising more, or making dietary changes.

Problems with any part of the heart can become life-threatening.

The heart ensures the body has a constant supply of oxygen-rich blood, and the valves open and close each time the heart beats and ensure that the blood flows in the right direction.

When they do not function correctly, the heart has to work harder, increasing the risk of heart conditions and complications.

People with heart valve problems should consult a doctor about options for safely treating their symptoms.