Cardiac Tamponade

Cardiac Tamponade

The heart is enclosed in a fibrous called the pericardium, and in between the heart and the pericardium is a small amount of fluid called the pericardial fluid. This fluid serves as a lubricant to allow the heart to move or beat freely.

Cardiac tamponade is a condition wherein the amount of fluid in the pericardim suddenly increases, causing an increase in pressure around the heart and thus making it hard for the organ to move and pump blood. The excess fluid is usually an effusion from a malignancy/tumor, pericarditis or heart attack, or blood from a tear in the vessels or trauma.

Due to the pressure around the heart, the diastolic pressures in the atria, ventricles and pulmonary become equal, causing the signs and symptoms of the tamponade. The patient becomes anxious and complains of chest pain and difficulty of breathing, which may be somewhat relieved by sitting up or leaning forward. Rapid heart and respiratory rates are usually noted. On auscultation, hearts sounds are faint or distant* and a pericardial rub may be heard. The patient may have a positive Kussmaul’s sign, and pulsus paradoxus may be present. Blood pressure falls* as the tamponade advances due to persistent decrease in cardiac output. Additionally, neck veins may be distended* and peripheral pulses weak or absent.

Cardiac tamponade is an emergency and should be addressed immediately. However, in order to properly manage the patient, it must be differentiated from other conditions that may have similar signs and symptoms, including constricitive pericarditis, cardiogenic shock, pulmonary embolism and pneumothorax. Though a number of tests have been (and are still being) used, the modality of choice for confirming the diagnosis of cardiac tamponade is echocardiography, which allows fluid to be directly visualized. Chest x-ray may show an enlarged heart with the shape of a water bottle. A12-lead electrocardiogram may show sinus tachycardia and electrical alternans, though these findings are only suggestive of tamponade. Swan-Ganz catheterization may demonstrate equalization of the pressures in the heart chambers.

Aside from initial support for the patient, including provision of oxygen, drugs and volume expanders, pericardiocentesis must be performed as soon as possible to relieve the pressure around the heart. This procedure would involve aspiration of the pericardial fluid with a needle, and is preferably guided by an echocardiogram. If the tamponade is recurrent, surgical intervention may be necessary, either though the creation of a pericardial window, a pericardio-peritoneal shunt, pericardiodesis or pericardiectomy. Finally, once the patient is stabilized, the primary cause of the tamponade should be addressed.

The prognosis of cardiac tamponade depends on its severity on diagnosis and initiation of treatment. In a study by Swaminathan et al. in South-West England, 3.2% of deaths over a 10-year period are caused by cardiac tamponade.

* Beck triad

Swaminathan A, Kandaswamy K, Powari M and Mathew J. Dying from cardiac tamponade. World Journal of Emergency Surgery. 2007;2:22. Accessed online at http://www.wjes.org/content/2/1/22 on February 15, 2011.

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