The removal of fluid from the pericardial space is called pericardiocentesis. The abrupt collection of fluid raises intrapericardial pressure, compresses the heart, and decreases cardiac output. This condition is called cardiac tamponade. Echocardiography is recommended to make urgent diagnosis and look for diastolic collapse of the right atrium and ventricle due to cardiac tamponade. Immediate aspiration of fluid is recommended in such a case.