Echocardiography is critical for the identification of a pericardial effusion and rapid diagnosis of pericardial tamponade.
Common echocardiography findings that suggest tamponade include diastolic right ventricular collapse, systolic right atrial collapse, a plethoric IVC with minimal respiratory variation, and potentially exaggerated respiratory cycle changes in mitral and triscupid inflow velocities.
Of these, systolic right atrial collapse is the earliest echocardiographic sign of tamponade, with a sensitivity ranging from 50% to 100%.
Of the 4 standard echo views, systolic right atrial collapse can best be viewed in the apical 4-chamber and subxiphoid views.
Alerhand S, Carter JM. What echocardiographic findings suggest a pericardial effusion is causing tamponade? Am J Emerg Med. 2019; 37:321-6.