Cardiac Tamponade vs Pericardial Effusion

Cardiac Tamponade vs Pericardial Effusion

The pericardium is a protective sac that wraps up the heart and plays a vital role in maintaining its normal function. This membrane typically has a small amount of fluid between its layers. When there is excess fluid that accumulates within the pericardial space, it can lead to two different conditions: cardiac tamponade and pericardial effusion.

Although both involve fluid buildup, it’s essential to understand what differentiates one from the other because of their implication on cardiovascular health.

In this article, we will explore what is cardiac tamponade and pericardial effusion, review their symptoms and characteristics, revise the diagnostic methods, the treatment options, and what are the key differences from one another.

What is a Pericardial Effusion?

Pericardial effusion is the abnormal accumulation of fluid within the pericardial sac, a double layer of thin membrane outlining the heart, which normally does not exceed 50 ml.

The possible causes of this development are pericardial fluid overproduction because of pericardial inflammation due to infectious or noninfectious causes:

Infectious causes:

  • The most common agents are viruses.
  • Tuberculosis in developing countries.

Noninfectious causes:

  • Autoimmune
  • Autoinflammatory
  • Metabolic diseases

Other causes:

  • Trauma
  • Decrease reabsorption of fluid due to cancer invasion of draining vessels
  • Heart failure
  • Liver cirrhosis
  • Nephrotic syndrome
  • Iatrogenic due to surgery or other interventions
  • Endocrine (e.g., hypothyroidism)
  • Drug-induced
  • Radiation related

Pericardial effusion clinical manifestations range from asymptomatic to severe, depending mainly on the accumulation rate and the cause. This is why it can be classified as acute or chronic.

Acute pericardial effusion: symptoms of acute pericardial effusion are usually mild, unspecific, or go unnoticed, while the symptoms of the underlying cause of the effusion may predominate.

Chronic pericardial effusion: may allow the elastic fibers of the pericardium to stretch, causing minimal effects on the normal cardiac pumping function. Therefore, it may be asymptomatic.

How is a Pericardial Effusion Diagnosed?

One of the first complementary exams that are used to diagnose pericardial effusion is the echocardiographic exam because it is very reliable and can be used at the bedside.

What the physician will be able to see with this technique is an echo-free (black) space between the two layers of the pericardium and will be able to assess:

  • If the effusion is localized or generalized
  • What the characteristics of the fluid are.
  • How much fluid there is.
  • What the consequences on the heart are.
  • The density of the fluid.
  • The presence of clots.

Other imaging techniques, like chest X-ray (CXR), computerized tomography (CT), or magnetic resonance imaging (MRI), can be helpful for further evaluation if needed, as well as a complete clinical assessment and laboratory testing.

How is a Pericardial Effusion Treated?

The management of pericardial effusion depends on its underlying cause, severity, and associated symptoms.

In small and asymptomatic pericardial effusion, conservative management and observation are necessary.

The larger or symptomatic effusions may require drainage via interventions like pericardiocentesis or surgical drainage..

Surgical Procedures

The pericardiocentesis is a procedure in which a needle is inserted through the chest to drain the pericardial fluid. It is usually carried out with ultrasound guidance before, during, and after the procedure to reduce the incidence of major complications. The surgeon accesses through the chest, usually subcostal, with a catheter. The most common technique is called the Seldinger technique.

A pericardial window surgery is a minimally invasive procedure where a small part of the sac is removed to drain the extra fluid to the pleural cavity (the sac that surrounds the lungs).

Both of these techniques are safe and effective treatment strategies.

Physicians treat and manage the underlying cause, such as infection or inflammation, to prevent recurrence.

What is a Cardiac Tamponade?

Cardiac tamponade is an emergency where the pressure of the pericardial sac increases beyond the pericardial adaptation capacity because an abnormal accumulation of fluid impedes normal cardiac blood filling. When this happens rapidly, the amount of blood that goes into the heart reduces, impeding the normal blood flow, which can lead to cardiac arrest and death.

Less frequently, this compression can happen due to a localized mass or tumor or because of an accumulation of blood near the heart, for example, after chest surgery. Also, it is important to note that all pericardial effusions can evolve into a tamponade.

The rapidity with which the fluid accumulates will determine the clinical manifestations.

Several clinical presentations are possible, like:

  • Acceleration of the heart beating (tachycardia).
  • Feeling of breathlessness (dyspnea).
  • Elevation of the pressures in the veins of the neck (distended jugular veins).
  • Decreased blood pressure and impaired circulation to the organs (shock).
  • Pulsus paradoxus (the systemic blood pressure decreases during inspiration).

How is a Cardiac Tamponade Diagnosed?

To diagnose cardiac tamponade, emergency echocardiography using both imaging mode and Doppler mode is the first method for rapid diagnosis and assessing the severity of the tamponade.

With this method, physicians are able to assess:

  • The quantity and quality of pericardial fluid.
  • Collapsibility of cardiac chambers.
  • Cardiac chambers’ size variability with the respiratory cycle.
  • Movement in the ventricular septum (the wall between both ventricles).
  • Collapsibility of the inferior vena cava.
  • Respiratory variation of flow patterns through the heart valves.
  • Hepatic and pulmonary veins flow patterns.

Additional tests, like electrocardiogram (ECG) and chest X-ray, may be useful to evaluate the severity of tamponade and identify potential underlying causes. However, in patients with severely decreased blood pressure and impaired cardiac function, treatment measures are not delayed for further study.

How is a Cardiac Tamponade Treated?

When possible, ultrasound-guided pericardiocentesis is used to drain the pericardial fluid with a needle or a catheter, with high success rates and low morbidity.

We have to remember that cardiac tamponade is a life-threatening medical emergency and requires immediate intervention.

What are the Differences Between Cardiac Tamponade and Pericardial Effusion?

Hemodynamic Stability

Cardiac tamponade frequently presents hemodynamic compromise, meaning low blood pressure and signs of impaired blood flow to the rest of the body since the filling and pumping capacity of the heart is impaired.

Pericardial effusion can range between asymptomatic to mild and moderate symptoms without significant hemodynamic compromise.

Onset and Progression

Cardiac tamponade develops at a rapid rate, leading to sudden and severe symptoms. Pericardial effusion, more frequently, has a slower onset and progress, allowing for more gradual symptom development.

Potential Causes

While the causes of pericardial effusion can be varied, like infections, inflammation, malignancies, or autoimmune disorders, cardiac tamponade often occurs due to acute causes like trauma, heart wall rupture, or aortic dissection (a tear to the aortic wall).

Frequently asked questions about cardiac tamponade vs. pericardial effusion.

Can cardiac tamponade or pericardial effusion recur?

Yes, both cardiac tamponade and pericardial effusion can recur if the underlying cause is not treated. It is very important to treat the cause and have a follow-up directed by the physicians to prevent a recurrence.

Can cardiac tamponade or pericardial effusion be prevented?

Although neither cardiac tamponade nor pericardial effusion can be prevented, there are certain measurements that are taken to reduce the risk:

  • Seek medical attention if symptoms of infections appear.
  • Follow precautionary measures to prevent traffic accidents.
  • If on anticoagulant medications, follow your physician's monitoring directives.
  • Have regular follow up with your clinician.
  • Seek attention and management of any underlying disease that can cause pericardial effusion.

Is pericardial effusion always symptomatic?

No, when pericardial effusion has a slow accumulation of fluid, it can go unnoticed and be discovered incidentally in a routine visit to the doctor.

Is pericardial effusion always a precursor of cardiac tamponade?

No, the development of cardiac tamponade depends on factors like the volume and velocity of fluid accumulation, the elasticity of the pericardium, and individual factors. While pericardial effusion can lead to cardiac tamponade, many cases are mild and asymptomatic and resolve on their own without progressing to cardiac tamponade.


Cardiac tamponade and pericardial effusion are two conditions produced by the accumulation of fluid within the pericardial space. While pericardial effusion may range from asymptomatic to causing mild to moderate symptoms, cardiac tamponade is a medical emergency with severe symptoms and possible hemodynamic compromise.

Ultrasound serves as a primary diagnostic tool, enabling the visualization of pericardial fluid accumulation and assessing cardiac function.

Treatment approaches vary depending on the severity, underlying cause, and associated symptoms. Pericardiocentesis or pericardial window surgery may be necessary for immediate relief and restoration of cardiac function.

Early detection and appropriate management of cardiac tamponade and pericardial effusion are essential for minimizing potential complications and optimizing patient outcomes.

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