Differentiating pericardial effusion from pericardial tamponade on ultrasound

Tamponade physiology, in which a pericardial effusion impedes cardiac output, is a medical emergency and requires prompt diagnosis and intervention before cardiovascular collapse ensues. However, not every fluid collection in the pericardial sac results in tamponade physiology. A clinical diagnosis of tamponade (Beck’s triad) has poor sensitivity and will occur only in the late stages of tamponade.^​1​ In order to know whether or not an intervention is necessary for the setting of pericardial effusion, ultrasound diagnosis of tamponade is paramount.