What to Know: Pericardial Effusion

Medically Reviewed by James Beckerman, MD, FACC on August 20, 2022
4 min read

A pericardial effusion is excess fluid between the heart and the sac surrounding the heart, known as the pericardium. Many are not harmful, but they sometimes can make the heart work poorly.

The pericardium is a tough and layered sac. When your heart beats, it slides easily within it. Normally, 2 to 3 tablespoons of clear, yellow pericardial fluid are between the sac's two layers. That fluid helps your heart move easier within the sac.

If you have a pericardial effusion, much more fluid sits there. Small ones may contain 100 milliliters of fluid. Very large ones may have more than 2 liters.

In most cases, inflammation of the sac, a condition called pericarditis, leads to the effusion. As it becomes inflamed, more fluid is produced.

Viral infections are one of the main causes of the inflammation and the effusions it leads to. These infections include:

  • Cytomegalovirus
  • Coxsackieviruses
  • Echoviruses
  • HIV Infection
  • Lupus
  • Tuberculosis

In these cases, treating the underlying medical condition will often help treat the effusion.

Other conditions that can cause these effusions include:

In many cases, no cause can be found. Your doctor may call these idiopathic pericardial effusions.

When inflammation of the sac causes a pericardial effusion, the main symptom is chest pain. It may get worse when you breathe deeply and better when you lean forward.

Other symptoms may include:

When there’s no inflammation of the sac, there are often no symptoms.

Large, serious pericardial effusions, or smaller ones that develop quickly, may cause symptoms that include:

  • Shortness of breath
  • Palpitations (sensation that the heart is pounding or beating fast)
  • Light-headedness or passing out
  • Cool, clammy skin

A pericardial effusion with these symptoms is a medical emergency and may be life-threatening.

Because these often cause no symptoms, they’re frequently discovered after the results of routine tests are abnormal. These tests can include:

Physical examination: A doctor may hear abnormal sounds over the heart that can suggest inflammation. However, pericardial effusions usually can’t be found through a physical.

Electrocardiogram (EKG): Electrodes placed on your chest trace the heart's electrical activity. Certain patterns on an EKG can signal a pericardial effusion or the inflammation that leads to it.

Chest X-ray film: The heart's silhouette on one may be enlarged. That’s a sign of a pericardial effusion.

If one is suspected, the best test to confirm it is an echocardiogram (ultrasound of the heart) because your doctor would easily see any excess fluid.

Once the effusion is identified, its size and severity are figured out. Most times, it’s small and causes no serious problems. If it’s large, it can compress your heart and hamper its ability to pump blood. This condition, called cardiac tamponade, is potentially life-threatening.

To find the cause of a pericardial effusion, your doctor may take a sample of the pericardial fluid. In this procedure, called pericardiocentesis, a doctor inserts a needle through your chest, into your pericardial effusion, and takes some fluid.

It depends on its severity and cause. Small ones that don’t have symptoms and are due to known causes (for example, kidney failure) require no special treatment.

For pericardial effusions due to inflammation of the sac, treating the inflammation also treats the effusion.

In that case, you may be given:

If a severe infection or heart impairment (cardiac tamponade) exists, the extra fluid must be drained immediately. Drainage is done in two ways:

Pericardiocentesis: A doctor inserts a needle through the chest into the pericardial effusion. A catheter is put into the fluid, and it’s suctioned out.

Pericardiectomy or pericardial window: A surgeon makes an incision in the chest, reaches in, and cuts away part of the pericardium. This drains the pericardial effusion and usually prevents it from coming back. The procedure requires general anesthesia.

Pericardial effusions that are 3 months old or older are called chronic. Often, no cause is known. They’re sometimes monitored without treatment. If there are symptoms or your heart is being harmed, drainage is usually done.