Cardiac Tamponade

What is Cardiac Tamponade?

Cardiac tamponade involves a rapid increase in intrapericardial pressure, which impairs diastolic filling of the heart. The increase in pressure usually results from blood or fluid accumulation in the pericardial sac. If fluid accumulates rapidly, as little as 250 ml can create an emergency situation. Slow accumulation and an increase in pressure, as in pericardial effusion associated with cancer, may not produce immediate signs and symptoms because the fibrous wall of the pericardial sac can gradually stretch to accommodate as much as 1 to 2 L of fluid.

Causes of Cardiac Tamponade

Cardiac tamponade can happen acutely, such as from a stab wound, from surgery, or from the heart muscle rupturing. Heart rupture will usually happen (though it is very uncommon) around the site of myocardial infarction. Chronic cardiac tamponade is a slower process, where up to two litres of fluid can enter the pericardial space over a period of time, the pericardium stretching to accommodate.

Signs & Symptoms of Cardiac Tamponade

When tamponade occurs because of trauma, the sound of the heart beats can become faint, and the blood pressure in the arteries decreases, while the blood pressure in the veins increases.

In cases of tamponade caused by more slowly developing diseases, shortness of breath, a feeling of tightness in the chest, increased blood pressure in the large veins in the neck (the jugular veins), weight gain, and fluid retention by the body can occur.

Diagnostic Tests

When cardiac tamponade is suspected, accurate diagnosis can be life-saving. The most accurate way to identify this condition is by using a test called an echocardiogram. This test uses sound waves to create an image of the heart and its surrounding sac, making it easy to visualize any fluid that has collected inside the sac.

Treatment

The goal of treatment is to relieve intrapericardial pressure and cardiac compression by removing accumulated blood or fluid. Pericardiocentesis (needle aspiration of the pericardial cavity) or surgical creation of an opening dramatically improves systemic arterial pressure and cardiac output with aspiration of as little as 25 ml of fluid. A drain may be inserted into the pericardial sac to drain the effusion. This may be left in until the effusion process stops or the corrective action (pericardial window) is performed.

In the hypotensive patient. trial volume loading with LV. normal saline solution with albumin, and perhaps an inotropic drug such as dopamine is necessary to maintain cardiac output.

Depending on the cause of tamponade. additional treatment may include:

• in traumatic injury, blood transfusion or a thoracotomy to drain reaccumulating fluid or to repair bleeding sites.
• in heparin-induced tamponade, the heparin antagonist protamine
• in warfarin-induced tamponade, vitamin K.

Prevention Tips

Many cases are not preventable. Awareness of your personal risk factors may allow early diagnosis and treatment.