What is a left atrial enlargement?

The left atrium is one of four chambers in the heart and is located on the upper left-hand side. The lower chambers are known as ventricles.

The right side of the heart is responsible for pumping blood to the lungs to collect oxygen in a process called oxygenation, while the left side pumps blood to the rest of the body.

Several heart problems can cause the left atrium to swell. When this happens, it is called left atrial enlargement. It is linked to several conditions, including atrial fibrillation and heart failure.

In this article, learn about the causes of left atrial enlargement and the symptoms of conditions related to left atrial enlargement, as well as the treatment options.



digital illustration of heart
The left atrium is located on the upper left-hand side of the heart.

Health conditions associated with left atrial enlargement do not always cause symptoms, and someone may only discover it during a test for another problem.

When people have symptoms associated with other heart conditions, these symptoms include:

  • breathlessness or shortness of breath
  • fatigue
  • rapid or irregular heartbeats (palpitations)
  • lack of appetite or nausea
  • dizziness or light-headedness
  • fluid buildup and swelling
  • weight gain
  • chest pain
  • fainting



The size of the left atrium depends on the size of the individual and may change as a person ages.

Conditions that may cause left atrial enlargement include:

High blood pressure

doctor taking female patients blood pressure
Research has shown there is a link between high blood pressure and left atrial enlargement.

Left atrial enlargement can help doctors predict cardiovascular events, such as heart attacks.

Research has found a link between left atrial enlargement and both treated and untreated high blood pressure or hypertension.

Diagnosing left atrial enlargement can help doctors determine the risk of a heart attack in people with high blood pressure.

Problems with the mitral valve

Oxygenated blood passes through the mitral valve from the left atrium to the left ventricle. Problems with the mitral valve can lead to left atrial enlargement.

Possible conditions include:

  • Mitral stenosis, which is when the valve narrows and makes it difficult for blood to pass from the atrium to the ventricle.
  • Mitral regurgitation, which is when the blood leaks from the left ventricle back into the left atrium. In healthy people, the mitral valve only flows one way, passing from the atrium to the ventricle.

If mitral stenosis or regurgitation is severe, it may be difficult for the blood to pass to the ventricle. The left atrium will enlarge to compensate for the increased pressure it is under.

Left ventricle dysfunction

Problems with the left ventricle may mean it is unable to take the blood passed from the left atrium.

Again, the increased pressure that this creates in the left atrium can cause it to enlarge.


A doctor will use an echocardiogram to look for left atrial enlargement. This test uses high-frequency sound waves or ultrasound to produce pictures of the heart.

To do this test, a person will lie on a table, and a specially trained technician will attach small metal disks called electrodes to their chest. The technician will pass a small probe over the chest that produces sound waves. These sound waves bounce off the heart and echo back to the probe, making images.

An echocardiogram does not hurt, causes no internal harm, and has no side effects.

A doctor may also recommend magnetic resonance imaging (MRI) or a computed tomography (CT) scan for diagnosis.


Left atrial enlargement is associated with the following complications:

Atrial fibrillation

Atrial fibrillation or A-fib refers to frequent irregular heartbeats, which is called arrhythmia. It affects around 2.7 million Americans.

A-fib can lead to blood clots, stroke, heart failure, and other heart problems.

Several studies have identified the link between left atrial enlargement and atrial fibrillation. In general, the larger the left atrium grows, the higher a person’s chances are of experiencing A-fib.


Stroke is the third leading cause of death in the United States. It can also cause severe complications and disability.

While the link between left atrial enlargement and stroke is complex, having A-fib increases someone’s chance of having a stroke.

There is also some evidence of an enlarged left atrium being a predictive marker of stroke without any signs of A-fib.

Heart failure

When someone has left atrial enlargement, it can also be a sign of congestive heart failure.

Heart failure occurs when a person’s heart cannot pump enough blood to meet the needs of the body.

It can lead to fatigue, weight gain, and a buildup of fluid in the lungs, liver, and the legs. As it progresses, it can cause shortness of breath and an irregular heartbeat.


healthy food in heart shape with stethoscope
A healthful diet will be beneficial to those with high blood pressure.

There is no treatment for left atrial enlargement. However, doctors will focus on identifying and treating the underlying cause.

Treatment for hypertension may include:

  • taking medication, including beta-blockers, diuretics, ACE inhibitors, and calciumchannel blockers
  • eating a healthful diet low in salt
  • limiting alcohol
  • exercising regularly
  • managing stress levels
  • maintaining a healthy weight
  • quitting smoking

Treatment for mitral stenosis may include:

  • taking diuretics to reduce fluid buildup
  • using blood thinners to prevent clots
  • taking anti-arrhythmic drugs for an irregular heartbeat
  • having surgery to replace or repair the mitral valve

Treatment for mitral regurgitation may include:

  • taking anticoagulant medication to reduce the risk of clots
  • having surgery to repair or replace the mitral valve

Treatment for left ventricle dysfunction may include:

  • taking angiotensin-converting enzyme (ACE) inhibitors
  • taking beta-blockers
  • using an implantable cardioverter defibrillator (ICD)

An ICD is a battery-powered device implanted under the skin with thin wires to the heart. It tracks a person’s heart rate and uses an electric shock to correct any dangerous heart rhythms.


Some lifestyle changes may lower the risk of developing conditions that are associated with left atrial enlargement. These include:

  • managing high blood pressure and high cholesterol
  • eating a healthful diet rich in fruits and vegetables
  • reducing or eliminating alcohol
  • quitting smoking
  • exercising regularly
  • losing weight if overweight
  • practicing good stress management


While many people who have left atrial enlargement experience no symptoms, it may be a sign of an underlying heart condition.

Treatment of the heart conditions associated with left atrial enlargement can vary from simple lifestyle changes to surgery, so it is essential to receive a proper diagnosis.

What is a left atrial enlargement?
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