Figure 1
Pressure-volume relationship in pericardial tamponade. Rapid-onset effusions cause tamponades at smaller volumes (grey line) than chronic effusions (red line), allowing gradual pericardial stretch and accommodating larger fluid volumes before hemodynamic compromise.
Figure 2
Echocardiographic evaluation of pericardial effusion (standard views). (A) Two-dimensional (2D) apical four-chamber view showing anechoic pericardial space fluid collection (marked as 
) with fibrin strands (marked with arrow) suggestive of pericardial effusion. (B) 2D parasternal long-axis view showing similar fluid collection in the pericardial space (marked as ), notably anterior to the descending aorta, which differentiates from posteriorly located pleural effusion. (C) 2D short-axis view through the mid-left ventricular cavity, and (D) 2D subcostal view showing circumferential pericardial effusion (marked as ). Ao: aorta; DAo: descending aorta; LA: left atrium; LV: left ventricle; RA: right atrium; RV: right ventricle
Figure 3
Echocardiographic evaluation of pericardial tamponade. (A) Two-dimensional echocardiography showing typical inferior vena cava plethora (> 20 mm), with blunted respirophasic changes of less than 50%. (B) M-mode echocardiography through RV over one-third of the cardiac cycle in a patient with a large pericardial effusion with tamponade physiology (marked with arrows). (C) Pulse-wave Doppler through the mitral valve inflow shows a variation in peak velocity with respiration in the patient with cardiac tamponade. The peak mitral valve E-velocity of 78 cm/s (expiration) and 43 cm/s (inspiration), with 45% drop in E-velocity. (D) Pulse-wave Doppler through the tricuspid valve inflow in a similar patient showing > 50% drop in velocity with respiration cycle. (E) Pulse-wave Doppler through hepatic veins showing typical flow reversal in cardiac tamponade. (F) Schematic diagram showing comparison of normal biphasic hepatic vein flow on pulse-wave Doppler with diastolic flow reversal in cardiac tamponade. IVC: inferior vena cava; HV: hepatic vein; RA: right atrium; Exp: expiration; Insp: inspiration
Figure 4
Computed tomography (CT) assessment of pericardial effusion. (A) Contrast-enhanced CT (axial view) demonstrating a large circumferential pericardial effusion (marked as ) with simple fluid attenuation (0-20 Hounsfield units) suggestive of transudative process. (B) Similar patient’s CT showing dilated inferior vena cava, suggesting elevated right atrial pressure.
Figure 5
Cardiac magnetic resonance (CMR) assessment of pericardial effusion. (A) A cine still frame of a two-chamber view, and (D) four-chamber view shows a large circumferential pericardial effusion of simple fluid. (B) Late gadolinium enhancement imaging on CMR shows a large circumferential pericardial effusion with mild pericardial enhancement, suggestive of fibrosis. (C) T2-weighted imaging shows increased signal in the visceral and parietal pericardium in suggestive of active pericardial edema.