Cardiac tamponade is an uncommon condition characterized by the accumulation of fluid in the pericardium (the sac surrounding the heart). This fluid can put so much pressure on the heart that it is unable to pump enough blood to meet the body’s demands. Fluid accumulation in the pericardial sac is known as pericardial effusion. Cardiac tamponade results when fluid collects rapidly or in large amounts, which interferes with the heart's ability to pump and fill with blood. 

Cardiac tamponade can be caused by trauma (such as a car accident), a coronary event (such as a heart attack) or cancer. Among the most common causes of tamponade are inflammation of the pericardium (pericarditis) and toxic accumulation in the blood, which is usually a result of kidney disease. However, other conditions may cause it as well.

Treatment for cardiac tamponade involves removing the fluid from the pericardium, which may be done with a needle and catheter combination (pericardiocentesis), balloon-tipped catheter or surgery. People at high risk for developing cardiac tamponade are urged to take anti-inflammatory medications and to learn the symptoms of cardiac tamponade in order to get immediate medical treatment at the first sign of danger.

Cardiac tamponade is a serious but uncommon condition characterized by excessive fluid in the pericardium (the sac surrounding the heart). Normally, the pericardium contains about 25 milliliters of this pale, yellow fluid. The fluid insulates and protects the heart. It also limits the outward movement of the heart’s chambers atria and ventricles.

However, too much fluid building up in the pericardium (from blood or other fluids leaking into the sac) puts pressure on the heart muscle, decreasing the heart’s ability to fill with and circulate blood. Cardiac tamponade that occurs rapidly is known as acute cardiac tamponade. This may be the result of a sudden injury or surgical complication. It is a medical emergency that must be addressed immediately.

Cardiac tamponade that occurs more slowly is known as subacute cardiac tamponade. This may be the result of a disease such as cancer. The condition can sometimes be treated with medication aimed at reducing the quantity of fluid in the pericardial sac. If there is a possibility of it worsening into acute tamponade, however, it must be treated with surgery or possibly other less invasive techniques.

Although these conditions are treated similarly, they differ in the amount of fluid necessary to cause symptoms of tamponade. Acute cardiac tamponade can be caused by the rapid infusion of 200 milliliters (ml) of fluid into the pericardium. Subacute cardiac tamponade may be caused by as much as 2000 ml because the pericardium is able to stretch and accommodate more fluid. Symptoms of subacute cardiac tamponade may be similar to heart failure (e.g., breathlessness, distended neck veins).

Cardiac tamponade may be caused by any of the following:

• Critical illnesses such as advanced cancer or renal kidney failure
  
  
• Pericarditis (inflammation or scarring of the pericardium)
  
  
• Penetrating traumas, such as from an accident, knife or gunshot wound
  
  
• Non-penetrating (blunt) trauma, such as that caused by a steering wheel in automobile accidents
  
  
• Heart catheterization and invasive surgery, including open-heart surgery
  
  
• Recent heart attack
  
  
• Aortic aneurysm
  
  
• Radiation or drug therapies
  
  
• Lupus erythematosus and other connective tissue diseases
  
  
• Hypothyroidism (underactive thyroid gland)
  
  
• HIV (Human Immunodeficiency Virus) infection

Any of these conditions can lead to the leakage of blood or other fluids into the pericardial sac (pericardial effusion). During cardiac tamponade, the heart adapts to its restricted motion with an increase in heart rate (tachycardia) to maintain adequate cardiac output. Furthermore, the septum of the heart may be bowed into the left ventricle, impairing blood flow out of that chamber.

All these changes may lead to potentially fatal right-sided heart failure, abnormal heart rhythms (arrhythmias) or cardiogenic shock, or low blood flow to the body as a result of a lack of delivery of oxygen-rich blood.

Although dangerous, cardiac tamponade is a relatively uncommon occurrence in the United States. Only about 2 percent of penetrating trauma patients experience cardiac tamponade and, overall, approximately two out of every 10,000 persons will develop this condition.

Individuals who experience cardiac tamponade often describe one or more of these symptoms:

• Sharp chest pain, often related to pericarditis, dissipating by the time the more severe cardiac tamponade condition develops 
  
  
• Shortness of breath, sometimes as a result of breathing shallowly on purpose to avoid chest pain but usually, once cardiac tamponade has developed, related to reduced blood flow
  
  
• Forward-leaning posture due to pain and/or the need to catch one’s breath
  
  
• Weakness and/or fatigue
  
  
• Bluish tint to skin (cyanosis)
  
  
• Anxiety
  
  
• Swelling in the abdomen

Clinical signs, which may not be directly evident to the patient or through observation, include:

• Falling arterial blood pressure
  
  
• Rising venous blood pressure (which causes the distended jugular veins in the neck as returning blood can't flow into the heart)
  
  
• Tachycardias (rapid heart rhythms) and muffled heart sounds
  
  
• Narrowed pulse pressure (a decrease in the difference between systolic and diastolic measurements)
  
  
• Significant decline of pulse volume and systolic blood pressure during inhalation

Several diagnostic tests can be used to help the physician to diagnose cardiac tamponade and rule out other conditions. Tests typically include:

• Echocardiogram. This test uses sound waves to visualize the structures and functions of the heart. It may reveal a buildup of fluid in the pericardium, abnormal heart movements (a “swinging heart”) and/or a dilated vena cava. Echocardiograms can also be used to exclude other possible causes for the symtoms, including tumors, constrictive pericarditis, cardiomyopathy and blood clots. In addition, a Doppler ultrasound may be done to measure blood flow. This test may show insufficient diastolic (relaxation) activity in the right atrium and right ventricle. It may also reveal heart valve obstruction or leakage as the cause of the bulging neck veins.
  
  
  
  
  
• Electrocardiogram (EKG). A recording of the heart’s electrical activity as a graph on a moving strip of paper or video monitor. The test, in the presence of cardiac tamponade, often exhibits low electrical voltage.
  
  
  
  
  
• Chest x-ray. The x-ray may show an enlarged cardiac “silhouette” due to an excessive volume of pericardial fluid, especially when more than 200 milliliters of fluid has built up in the pericardium.

Acute cardiac tamponade is considered a medical emergency. Diagnostic tests will be performed quickly and comprehensively to determine the appropriate course of treatment. Treatment will focus on the immediate reduction of fluid in the pericardial sac.

The treatment for cardiac tamponade is to aspirate (drain or remove through suction) fluid from the pericardium. This invasive process is known as pericardiocentesis. This technique entails numbing of the chest area with a local anesthetic followed by the insertion of a needle just below the breast bone (sternum) and into the pericardium. The needle is then replaced by a catheter and excess fluid is drained through the tube and into sterile containers.

Often, an echocardiogram is used to help guide the entry of the needle. This use of ultrasound imaging to assist in pericardiocentesis has greatly improved its safety and effectiveness. However, the procedure does have risks, and patients will be under close observation after the procedure. A hospital stay of several days should be expected, to monitor for a re-accumulation of fluid.

If pericardiocentesis is not successful, or if other complications are present, further intervention may be necessary. These procedures include the following:

• Percutaneous balloon pericardiotomy uses a balloon-tipped catheter to create a tear in the wall of the pericardium, through which a drainage tube can be inserted. The procedure only requires local anesthesia. It is most commonly performed in patients whose cardiac tamponade is cancer-related.
  
  
• Surgical pericardiotomy involves putting the patient “to sleep” with general anesthesia. The surgeon then makes a cut-down (incision) in the chest and pericardium to gain access for the drainage tube. Surgery is more likely if the fluid continues to re-accumulate, if the cause of the fluid accumulation remains obscure, or if the removal of the pericardial sac becomes necessary.
  
  
• Pericardiectomy is a type of operation in which part of the pericardium is surgically removed. This procedure may be done if scarring is present with cardiac tamponade or if a biopsy of the pericardium is necessary.

There are two main prevention strategies for cardiac tamponade, both of which are advised for people at high-risk of developing the condition:

• Taking anti-inflammatory medications (e.g., NSAIDs) to help prevent any fluid buildup in the pericardium from progressing to cardiac tamponade
  
  
• Learning the warning signs and symptoms of fluid buildup in the pericardium (pericardial effusion) and contacting a physician immediately if any of these are experienced.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about cardiac tamponade:

1. Am I at high-risk for this condition?
   
   
2. What tests will I receive to diagnose cardiac tamponade?
   
   
3. What may have caused this condition?
   
   
4. What type of cardiac tamponade do I have?
   
   
5. What are my treatment options?
   
   
6. What are the risks associated with these treatments?
   
   
7. Even if my pericardiocentesis was successful, can there be permanent damage to the pericardium?
   
   
8. What are the chances of re-accumulation of fluid?
   
   
9. Which symptoms indicate a medical emergency?
   
   
10. What can I do to prevent cardiac tamponade?
    
    
11. How will my condition be monitored after treatment?
    
    
12. Are my children at risk for cardiac tamponade?