Pericardium

Evaluate the pericardium for effusion, thickening, masses, inflammation, tamponade physiology, and constriction.

A normal pericardium may not be clearly visualized by TTE. Normal thickness on echocardiography does not exclude constrictive pericarditis.

Pericardial Effusion¶

Pericardial fluid appears as an echo-free space between the visceral and parietal pericardium.

Measure the largest separation at end-diastole and describe its location and distribution.

Effusion size	End-diastolic separation
Small	<10 mm
Moderate	10–20 mm
Large	>20 mm

Report:

Size
Circumferential versus localized
Location
Simple versus complex appearance
Fibrinous strands, septations, or echogenic material
Hemodynamic findings
Change from prior imaging

Small effusions are usually first seen posterior to the LV. As the effusion enlarges, it extends laterally and anteriorly.

Pericardial Versus Pleural Effusion¶

From the parasternal long-axis view:

Pericardial fluid lies anterior to the descending thoracic aorta.
Pleural fluid extends posterior to the descending thoracic aorta.

Epicardial fat is usually anterior, contains internal echoes, and moves with the heart.

Cardiac Tamponade¶

Tamponade is a clinical and hemodynamic diagnosis. Effusion size alone does not determine its presence.

A rapidly accumulating small effusion may cause tamponade, while a slowly accumulating large effusion may not.

Echocardiographic Findings¶

Right atrial systolic collapse
RV early-diastolic collapse
Plethoric IVC with reduced respiratory variation
Exaggerated respiratory variation in transvalvular flow
Swinging heart
Hepatic vein expiratory diastolic flow reversal
Progressive respiratory ventricular interdependence

Doppler Findings¶

Measurement	Finding supporting tamponade
Mitral E-wave velocity	>25% respiratory variation
Tricuspid E-wave velocity	>40% respiratory variation
Aortic outflow velocity	Marked respiratory variation
Hepatic vein flow	Expiratory diastolic reversal

Measure Doppler variation during quiet respiration at a sweep speed that displays multiple respiratory cycles.

Right atrial collapse is sensitive but less specific. Prolonged collapse lasting more than one-third of the cardiac cycle increases specificity.

RV diastolic collapse is more specific and usually begins in early diastole when pericardial pressure exceeds RV pressure.

Important Limitations¶

Typical right-sided chamber collapse may be absent with:

Pulmonary hypertension
RV hypertrophy
Positive-pressure ventilation
Severe LV failure
Elevated right-sided filling pressures

Localized postoperative effusions or hematomas may cause regional left-sided compression without classic right-sided collapse.

Constrictive Pericarditis¶

Constrictive pericarditis produces impaired diastolic filling, exaggerated ventricular interdependence, and dissociation between intrathoracic and intracardiac pressure.

Findings Supporting Constriction¶

Respirophasic interventricular septal shift
Early-diastolic septal bounce
Mitral inflow variation >25%
Increased or preserved medial mitral annular e′
Medial e′ greater than lateral e′
Hepatic vein expiratory diastolic flow reversal
Plethoric IVC
Preserved or reduced LV filling pressure estimate despite congestion

Typical tissue Doppler findings include:

Medial e′ ≥9 cm/s
Medial e′/lateral e′ ≥0.9

Annulus reversus: medial e′ exceeds lateral e′ because lateral annular motion is restricted by the pericardium.

Annulus paradoxus: E/e′ may be normal or reduced despite elevated filling pressure because medial e′ remains preserved.

Absence of visible pericardial thickening does not exclude constriction. CT and CMR better assess pericardial thickness, calcification, and inflammation.

Restriction Versus Constriction¶

Finding	Constriction	Restrictive cardiomyopathy
Respiratory septal shift	Present	Usually absent
Mitral inflow variation	Increased	Usually limited
Medial e′	Preserved or increased	Reduced
Medial versus lateral e′	Medial ≥ lateral	Lateral usually > medial
Hepatic vein reversal	Expiratory	Often inspiratory or nonphasic
Pericardium	May be thickened or calcified	Usually normal

Marked respiratory variation may be absent with volume depletion and exaggerated with COPD. Integrate all findings rather than relying on one parameter.

Effusive-Constrictive Pericarditis¶

Effusive-constrictive pericarditis combines pericardial effusion with visceral pericardial constriction.

Suspect it when constrictive physiology persists after pericardial drainage. Invasive confirmation demonstrates persistently elevated RA pressure despite normalization of intrapericardial pressure.

Suggested Reporting¶

No pericardial effusion is present.

A small circumferential pericardial effusion is present without echocardiographic evidence of tamponade physiology.

A large circumferential pericardial effusion is present with right atrial and right ventricular collapse and significant respiratory Doppler variation, concerning for tamponade physiology. Clinical correlation is required.

A localized postoperative pericardial effusion/hematoma compresses the ___ chamber.

Respirophasic septal shift, preserved medial e′ velocity, annulus reversus, and expiratory hepatic vein diastolic flow reversal are consistent with constrictive physiology.

Key Points¶

Measure effusion size at end-diastole and describe its distribution.
Tamponade depends on the rate of accumulation and chamber pressures, not size alone.
RV early-diastolic collapse is more specific than isolated RA collapse.
Typical collapse may be absent when right-sided pressure is elevated.
Preserved medial e′ and expiratory hepatic vein reversal favor constriction.
Normal pericardial thickness does not exclude constrictive pericarditis.
Echocardiographic tamponade physiology must be interpreted clinically.