Cardiac Tamponade Causes, Symptoms, and Treatments

Cardiac tamponade is a life-threatening condition in which an accumulation of fluid in the pericardial sac disrupts the normal function of the heart. 

The fluid that causes tamponade is usually either a typical pericardial effusion (that is, the accumulation of an abnormal amount of fluid in the pericardial sac) or bleeding into the pericardial sac. Cardiac tamponade can appear acutely, or it may develop rather gradually. In either case, symptoms are usually quite striking, and the resolution of symptoms requires the expeditious removal of the excess fluid from the pericardial sac.

How Is Cardiac Tamponade Produced?

Cardiac tamponade occurs when increased pressure within the pericardial sac, caused by the excess fluid, becomes sufficient to restrict the filling of the heart during diastole. Since the heart can no longer fill completely, less blood is ejected with each heartbeat, and the heart has to work much harder to supply the body's needs. Furthermore, the oxygenated blood returning to the heart from the lungs tends to back up, producing congestion in the lungs and veins.

The amount of pericardial fluid which is necessary to produce tamponade depends on how rapidly the fluid has accumulated. If pericardial fluid increases rapidly, the pericardium does not have time to "stretch," and the pressure within the pericardial space can increase greatly—even with a relatively small amount of fluid. On the other hand, if the pericardial fluid accumulates more gradually (say, over a period of days or weeks), the pericardium has time to stretch out to accommodate the extra fluid. In this case, the pressure within the pericardial space may not increase substantially until the pericardial effusion has become quite large, to the point at which the pericardium is incapable of stretching any further.

What Are The Causes of Cardiac Tamponade?

Cardiac tamponade can be caused by any of the conditions that produce pericardial effusion. These include:

• Pericarditis
• Dressler's syndrome
• Infections (viral, bacterial, or fungal)
• Autoimmune diseases such as lupus
• Chest trauma due to accident or surgical trauma
• Cancer
• Radiation therapy to the chest area
• Hypothyroidism
• Aortic dissection
• Drugs (especially hydralazine, isoniazid, and procainamide)

What Are The Symptoms of Cardiac Tamponade?

The type and severity of symptoms depend on whether the tamponade has developed acutely or gradually. Acute tamponade is most typically produced by chest trauma, cardiac surgery or other invasive cardiac procedures, such as cardiac catheterization, or by aortic dissection. In all these conditions, blood can fill the pericardial sac in a matter of seconds or minutes, producing a rapid and severe cardiac compromise. Because the excess fluid (that is, blood) in the pericardial sac accumulates rapidly in these conditions, tamponade can develop even with a relatively small amount of pericardial fluid. Symptoms are immediately striking and severe. Chest pain, severe shortness of breath, and tachycardia and palpitations are common. Very low blood pressure may occur, along with abnormally cool skin, bluish skin discoloration, and reduced output of urine.

Cardiac tamponade that results from conditions other than trauma, medical procedures, or aortic dissection tends to develop somewhat more gradually, usually over days or weeks. The pleural effusions in these "sub-acute" cases tend to be much larger than in acute cases since the pericardium usually has time to stretch out to accommodate the more gradual fluid accumulation. Symptoms are also less dramatic. Patients with sub-acute tamponade generally experience chest fullness or discomfort, easy fatigue-ability, shortness of breath with minimal activity, and edema in the legs and feet. But while symptoms may develop less dramatically than with acute tamponade, they can eventually become quite severe. This more gradual form of cardiac tamponade can also become fatal, and expeditious treatment is still necessary.

How Is Cardiac Tamponade Diagnosed?

The doctor will usually suspect cardiac tamponade by listening to the patient's symptoms, by the clinical circumstances (such as the suspected presence of any of the medical conditions known to cause tamponade), and by the physical examination. Additional clues can be obtained with a chest x-ray and an electrocardiogram. Once this condition is suspected, the diagnosis can be readily confirmed with an echocardiogram.

Clinically, it is sometimes difficult to tell the difference between cardiac tamponade and a similar condition called constrictive pericarditis, because the symptoms and the physical examination with these two conditions tend to be quite similar. However, most often echocardiography can readily distinguish between the two.

How Is Cardiac Tamponade Treated?

The treatment of cardiac tamponade is to remove the excess pericardial fluid from the pericardial sac. The removal of fluid immediately relieves the pressure within the pericardial sac and allows the heart to resume its normal function.

The removal of pericardial fluid is usually accomplished by means of a pericardiocentesis—that is, draining the fluid through a flexible catheter inserted into the pericardial space. Alternately, fluid removal can be accomplished through a surgical drainage procedure. Surgical drainage is usually done if, in addition to draining the fluid, a biopsy of the pericardium is needed for diagnostic reasons. If the pericardial effusion comes back after it has been drained, a pericardiectomy (surgical removal of the pericardium) may become necessary to prevent further recurrences.

A Word From Verywell

Pericardial tamponade is a life-threatening condition caused by an accumulation of fluid within the pericardial sac, causing a constriction of the heart. Because the removal of the excess pericardial fluid immediately restores cardiac function, it is important to rapidly diagnose and treat this condition.