Pericardial Effusion

Pericardial effusion is an accumulation of fluid in the pericardium, the sac that holds your heart. When it happens quickly or involves a large amount of fluid, the excess fluid can take up too much space in the pericardium, compressing your heart and causing a life-threatening condition known as cardiac tamponade.


Illustration of pericardial effusion, a buildup of excess fluid around the heart.
A normal heart vs. one with pericardial effusion.

What is the condition?

Pericardial effusion is a buildup of fluid in the space around the heart. It can happen for a wide range of reasons, including infections, injuries or other medical conditions. If the buildup is severe or happens quickly, it can compress your heart and cause cardiac tamponade, a life-threatening medical emergency.


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What is the difference between pericardial effusion and cardiac tamponade?

The pericardium is a double-walled sac that surrounds the heart. Between the inner wall of the pericardium and your heart is a thin layer of fluid, which cushions and protects your heart from outside forces (much like bubble wrap around a fragile item inside a shipping box).

Under normal circumstances, the pericardium has just enough fluid to cushion your heart, but not so much fluid that your heart can’t expand and fill up with blood with every heartbeat. Cardiac tamponade happens when there’s too much fluid inside the pericardium, which means your heart has no room to expand and fill up with blood. Without quick treatment, it can cause your heart to stop, which is eventually fatal within minutes to hours.

What is the difference between pericardial effusion and pleural effusion?

Pleural effusion is similar to pericardial effusion, but it happens in a different place inside your chest. The pleural cavity is the sac that surrounds your lungs, and a pleural effusion is when fluid fills up that space. A pleural effusion keeps your lungs from expanding as they should, which makes it harder for you to breathe.


Who does it affect, and how common is this condition?

Pericardial effusion can happen for a wide range of reasons. Because of that, it can happen to people of any age or background. It’s also a relatively common condition. However, there’s very little data on exactly how common it is. Sometimes, pericardial effusion is an incidental finding on an imaging test, meaning healthcare providers discover it without intending to.

How does this condition affect my body?

Every heartbeat starts with a pause where your heart muscle relaxes and expands. That lets the chambers of the heart fill up with blood before they squeeze. As the pericardium fills up, there's less space for your heart to expand. Eventually, your heart doesn’t have room to expand so its chambers can fill up with blood.

An easy way to see how pericardial effusion affects your heart is by trying to blow up a balloon inside of a plastic bottle. In this example, your heart is the balloon and the bottle is the pericardium. When the bottle is empty, there's more space for the balloon to inflate. If you add water to the bottle, there's less space and you can't blow up the balloon as much. If you keep filling the bottle, eventually you can't blow up the balloon at all.

As your heart pumps less and less blood, it speeds up to try to make up for its limited pumping ability. Over time, your heart can't keep up, and you go into cardiogenic shock, which makes your heart stop. Without treatment, cardiogenic shock is deadly.


Symptoms and Causes

What are the symptoms of pericardial effusion?

Pericardial effusions may not cause any symptoms, especially when they’re small or happen slowly. Symptoms are more likely when an effusion happens quickly, involves a large amount of fluid or causes cardiac tamponade. The main symptoms of pericardial effusions and cardiac tamponade include:

If a pericardial effusion is large enough, it can press on surrounding tissues or nerves. That can cause symptoms like:

What causes pericardial effusion?

Pericardial effusion can happen for many different reasons. It often happens along with (or because of) inflammation of the pericardium (pericarditis).

Possible causes of pericardial effusion include:

  • Infections. Pericardial effusion often happens because of viral or bacterial infections, including human immunodeficiency virus (HIV) and tuberculosis (though this is less common in developed countries). It can also happen because of fungal infections or parasites.
  • Cancer. Tumors in the heart or that spread from elsewhere in your body can cause damage to the pericardium.
  • Immune system conditions or inflammatory disorders. These include lupus, rheumatoid arthritis or Sjögren’s syndrome.
  • Hormonal disorders or problems. An example of this is hypothyroidism (where your thyroid gland isn’t producing enough thyroid hormone).
  • Trauma. Injuries to the chest, including blunt impacts (like car crashes) and punctures from knives or bullets, can cause pericardial effusion.
  • Heart or circulatory problems. These include heart attacks or aortic dissection (where layers on the inside of your aorta separate or tear).
  • Medical causes. Pericardial effusion can happen after heart surgery, radiation therapy for cancer or as a side effect of some medications.
  • Other. Pericardial effusion can also happen with heart failure, chronic kidney disease or kidney failure, liver cirrhosis or for unknown reasons.

Is pericardial effusion always a serious problem?

Pericardial effusion is usually a significant condition, but it isn’t always a medical emergency. Pericardial effusions may be small or large, and sometimes smaller effusions go away on their own. Whether or not it’s a life-threatening emergency depends on what caused it, the amount of fluid involved, and how fast that fluid fills the pericardium.

When an effusion happens quickly, it needs less fluid to become dangerous and cause cardiac tamponade. That's because the pericardium doesn't have time to stretch and expand to accommodate more fluid inside it. When a pericardial effusion happens slowly, it can take weeks or even months before it becomes a problem.

One factor that determines if a pericardial effusion is serious is why it happened in the first place. When it happens because of injuries or heart and circulatory problems (or any reason that can cause an effusion to develop quickly), pericardial effusion needs quick treatment to avoid dangerous complications like cardiac tamponade.

Is it contagious?

While pericardial effusion isn't contagious on its own, it can happen because of contagious infections.

Diagnosis and Tests

How is pericardial effusion diagnosed?

If you have symptoms, a doctor will diagnose pericardial effusion based on a combination of the symptoms you describe, your medical history, medical testing, and examining you for any signs and symptoms of this condition. Some of the key signs include an unusual drop in your blood pressure when you breathe in, muffled or unusual heart sounds, or bulging of the jugular vein in your neck.

If you don’t have symptoms, the most likely way a doctor will diagnose pericardial effusion is if they happen to see it on medical imaging for another reason. This kind of diagnosis is called an incidental finding, and an example of this is a pericardial effusion that’s visible on a chest X-ray after a car accident.

A wide range of tests is possible when healthcare providers evaluate your symptoms or suspect a pericardial effusion.

Imaging tests


This test measures the electrical activity of your heart through a set of sensors (usually 10) called electrodes, which attach to the skin of your chest. The electrodes detect your heart’s electrical activity and show it as a wave on either a paper printout or a screen display. Doctors can tell when your heart isn’t beating properly because its electrical activity changes in certain ways, some of which are very distinctive.

Lab tests

Lab tests usually come after a provider diagnoses pericardial effusion. These tests focus on finding out why you have a pericardial effusion. The possible tests include:

In some cases, tests on the fluid taken out of your pericardium are also possible. Testing the fluid can sometimes help doctors understand the underlying cause behind the effusion.

Management and Treatment

How is it treated, and is it curable?

Pericardial effusions are often treatable. Whether or not they’re curable depends on how severe they are and why they happened. Your healthcare provider is the best person to tell you what to expect from the treatment, including whether or not your effusion is curable.

What are the possible treatments?

Treatment of a pericardial effusion depends on how severe it is and what caused it. Small effusions or those that don’t happen for a dangerous reason often don’t need treatment.

When a pericardial effusion is large or causes cardiac tamponade, it becomes a medical emergency that needs immediate treatment. Potential treatments include:

  • Needle aspiration (pericardiocentesis): After numbing a specific area on your chest and using imaging tools (like echocardiography or fluoroscopy) for guidance, a healthcare provider will insert a needle into your chest until it is just inside the pericardium. They’ll then aspirate (pull out) the excess fluid inside. Sometimes, a thin, tube-like device is left inside the pericardium to drain fluid for a few days until it is all gone.
  • Surgery. In some cases, surgery is the best way to remove the extra fluid inside the pericardium. Surgery can happen in an emergency, or it can be a scheduled procedure when an effusion causes symptoms but is slow-growing and not dangerous. A common surgical procedure for this is video-assisted thoracic surgery (VATS), which creates a pericardial “window” to allow draining fluid to spill into the larger pleural cavity so it doesn’t fill up the pericardial space.

In cases where an effusion isn’t dangerous and doesn’t need any of the above treatments, it’s often possible to treat it with medications or other types of treatments. The treatments depend on the underlying cause. These include, but aren’t limited to, the following:

  • Antibiotics. These help by treating underlying infections, such as tuberculosis, which can cause pericarditis and effusions.
  • Anti-inflammatory drugs. These help reduce inflammation and swelling.
  • Chemotherapy and radiation therapy. These help when pericardial effusion happens because of cancer.
  • Diuretics and other heart failure medications. These help when heart failure is the cause behind a pericardial effusion.

Are there potential side effects or complications to the treatments?

The possible side effects with treatments for pericardial effusion depend strongly on which treatments or medications you receive. Your healthcare provider is the best person to tell you about what side effects are possible with the medications you take because they can tailor the information to fit your specific needs and circumstances.

A possible complication is pericardial decompression syndrome when you undergo a procedure or surgery to treat a pericardial effusion. While it isn't common, it is severe and life-threatening. It usually happens when fluid removal happens too quickly from a large effusion. To avoid this, your healthcare provider may drain the effusion more slowly.

How to take care of myself/manage symptoms?

Pericardial effusion isn’t something you should try to treat on your own unless you’ve spoken with a healthcare provider. That’s because it isn’t possible to diagnose it without specific medical tests and imaging. After getting this diagnosis, you can ask your healthcare provider what you can do to manage your symptoms and limit their impact on your life.

How soon after treatment will I feel better, and how long does it take to recover?

How long it takes you to feel better and recover depends on three main factors:

  • The cause of the effusion.
  • The severity of the effusion.
  • The treatments you received.
  • Your overall health and whether or not you have any other related medical conditions.

In cases where you have symptoms of cardiac tamponade, you should start to feel better as fluid removal decreases the pressure on your heart. In general, your healthcare provider is the best person to tell you the likely recovery time and when you should start to feel better.


How can I reduce my risk of developing this, or prevent it from happening entirely?

Pericardial effusion is unpredictable, so it’s usually impossible to prevent it. However, you can indirectly reduce your risk by avoiding circumstances that could cause one to happen. Those circumstances are:

  • Letting an infection go untreated for too long.
  • Engaging in risky activities, such as sports or outdoor activities with a greater risk of injury, without taking safety precautions like wearing protective equipment.

Outlook / Prognosis

What’s the outlook for this condition?

If you have a small or medium-sized pericardial effusion that is shrinking or not changing size, and you don’t have symptoms, you may not need any treatment. In these cases, your healthcare provider will probably want to monitor the effusion size and only recommend treatment if you develop symptoms or if there are other signs that it might be a problem.

If you have an effusion that’s growing more quickly, that’s causing symptoms, or that’s happening because of more serious conditions (especially trauma or cancer), you will probably need treatment sooner rather than later. If you have symptoms of cardiac tamponade, you need emergency medical attention immediately.

Overall, effusions that happen for unknown reasons tend to have a good prognosis. Effusions that happen because of trauma or cancer are more likely to have complications and are usually harder to treat.

How long does pericardial effusion last?

Large effusions and effusions that grow quickly are serious conditions that need quick medical care. That means these should not last any longer than it takes to diagnose and treat them, especially in emergency cases.

Chronic effusions, especially smaller ones that don’t cause symptoms, can last for weeks, months or even years. Depending on the circumstances, your healthcare provider may recommend regular follow-up visits to monitor the size of the effusion and whether or not it poses any risks to your health.

Living With

How do I take care of myself?

If you have a pericardial effusion, it’s important to watch for any symptoms or changes in your overall health. You should also follow your healthcare provider’s guidance, especially when it comes to taking medication and managing your recovery.

When should I call my healthcare provider?

Your healthcare provider can schedule follow-up visits to monitor your condition, if necessary. They can also give you guidance on how to manage your symptoms and when you should call their office.

When should I go to ER?

You should go to the hospital emergency room immediately if you have any of the following symptoms, which can be signs of cardiac tamponade:

A note from Cleveland Clinic

Pericardial effusion is a condition that can happen to people at any stage in life and for many different reasons. This condition can have little to no effect on your life when effusions are small and don't get bigger, or they can be medical emergencies when they affect how your heart functions. With quick diagnosis and treatment, many cases — depending on the underlying cause — are treatable, and some are curable.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 02/26/2022.

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