Cardiac tamponade is an accumulation of fluid in the pericardial sac that compresses the heart, impairs diastolic filling, and leads to a reduction in cardiac output. Tamponade is most often caused by penetrating trauma. Other causes of acute cardiac tamponade include aortic rupture and procedures such as pacer placement. Subacute cardiac tamponade can occur in the setting of malignancy or pericarditis. Beck’s triad is a collection of three signs associated with cardiac tamponade: distended neck veins, muffled heart sounds, and hypotension. Pulsus paradoxus is also suggestive, consisting of a decrease in systolic BP of > 10 mmHg during inspiration. Patients suspected of having cardiac tamponade should be evaluated with EKG, chest radiograph, and echocardiography. EKG may demonstrate low voltage and sinus tachycardia. Electrical alternans consists of beat-to-beat shifts in the QRS complex due to swinging of the heart in a large effusion. Treatment consists of the removal of pericardial fluid to relieve the elevated intrapericardial pressure and improve cardiac output. This can be achieved with pericardiocentesis (needle aspiration of the pericardial cavity), pericardial window (surgical creation of an opening), or pericardectomy (resection of a portion or all of the pericardium). Source
