•
•
The pericardial sac normally contains less than 50 ml of serous fluid, which may or may not be seen on 2D echocardiography. Pericardial fat may be mistaken for pericardial effusion. Pericardial fat, although echolucent, is only found on the anterior surface of the heart. Epicardial fat is seen around the heart with the exception of the LV wall, making the pericardium hard to visualize around the LV. An echolucent or echo-free space that surrounds the heart is a 2D sign of pericardial effusion and/or unclotted blood, best imaged in ME 4-chamber and TG mid-SAX views (Figure 15.1).
LA
LV
RA RV
Pericardial fluid
A
Pericardial effusion
LV SAX view
B
Figure 15.1 Pericardial effusion surrounding the heart seen in (A) ME 4-chamber and (B) TG SAX views.
Disease
PERICARDIAL EFFUSION •
15 Pericardial
PERICARDIAL DISEASE
Disease
15 Pericardial
In contrast, clotted blood will appear echodense and will likely be confined to a specific region.
Grading of Pericardial Effusion • • • •
Trivial: only seen in systole Small: posterior only, ≤ 1 cm Moderate: anterior and posterior, surrounding the heart, 1–2 cm Large: anterior and posterior, ≥2 cm
Pericardial versus Pleural Effusion •
Leftward turn of probe from ME 4-chamber view, see LA, LV, and descending aorta. u Left pleural fluid is an echolucent space shaped like a reverse crescent moon extending below the aorta (Figure 15.2). u Pericardial fluid will be present in the recess between the LA and the descending aorta.
Descending aorta Lung atelectasis Left pleural effusion
Figure 15.2 Left pleural effusion.
•
Transverse sinus: pocket of pericardium between aorta and pulmonary trunk.
When fluid-filled, it appears as an echo-free triangular space between the posterior wall of aorta and LA in the ME AV LAX view. If it contains fat, it may be mistaken for a mass. Oblique sinus: pericardium posterior to LA between pulmonary veins. Common site for blood to accumulate after cardiac surgery.
•
CARDIAC TAMPONADE •
Exists when pericardial pressure exceeds pressure in one or more of the cardiac chambers Physiology u RA or LA collapse in late diastole or early systole u RV collapse in early diastole u During spontaneous inspiration, blood rushes into the RV, causing RV expansion and deviation of septum toward the LV (and decreased LV volume). Termed paradoxical ventricular septal motion during inspiration or ventricular interdependence.
•
Note: Respiratory variations in ventricular filling are less predictable and have not been validated in mechanically ventilated patients.
SUMMARY OF ECHOCARDIOGRAPHIC FINDINGS IN TAMPONADE 2D •
RA collapse occurs in late diastole and early systole (happens first), when pressure is lowest; duration matters: 119
• •
•
collapse for > ⅓ of the cardiac cycle is pathognomonic for tamponade. RV collapse occurs in early diastole when pressure is lowest. Dilated IVC without diameter change during inspiration. Normally IVC diameter decreases or collapses by 50% with inspiration. With clot in pericardial space and regional tamponade, chamber collapse may not be seen.
Doppler •
•
• •
Respiratory (spontaneous) variation in mitral and tricuspid inflow patterns (E wave) (normally no change with respiration) u Inspiration: ↑ Etricuspid, ↓ Emitral u Expiration: ↓ Etricuspid, ↑ Emitral Positive (mechanical) pressure ventilation, in the absence of a located effusion, may show an exaggerated Doppler response that is reversed to that seen during spontaneous inspiration. Example: u Inspiration: ↓ Etricuspid, ↑ Emitral u Expiration: ↑ Etricuspid, ↓ Emitral With tamponade, mitral E velocity can exhibit 30% variation with respiration. With tamponade, tricuspid E velocity can exhibit 60% variation with respiration.
CONSTRICTIVE PERICARDITIS •
•
120
2D: pericardial thickening (>3 mm between bright regions); dilated IVC with <50% decrease in diameter with spontaneous inspiration, abnormal septal motion Doppler: E/A ≥2, short deceleration time (≤ 160 msec), normal e0 , IVRT varies with respiration, exaggerated respiratory variation of mitral E velocity (≥25%) (similar to tamponade)
Restrictive cardiomyopathy
Normal ECG
in
ex
in
ex
Constrictive pericarditis
in
ex
EA MVF EA TVF S D PVF Vr HVF
Ar
S D
DTI e′
a′
Figure 15.3 Differentiate constrictive pericarditis from restrictive cardiomyopathy. MVF, mitral valve inflow; TVF, tricuspid valve inflow; PVF, pulmonary vein flow; HVF, hepatic vein flow; DTI, tissue Doppler mitral annular motion. (Hoit B: Management of effusive and constrictive pericardial heart disease. Circulation 105: 2939–2942, 2002.)
Differentiate Constrictive Pericarditis from Restrictive Cardiomyopathy (Figure 15.3) •
•
Respiratory variation in E velocity is absent in restrictive cardiomyopathy (restrictive cardiomyopathy is not a disease of the pericardium). Tissue Doppler: e0 reduced in restrictive cardiomyopathy and normal in constrictive pericarditis. Similarly, color M-mode Vp is reduced in restrictive cardiomyopathy.
121
122
Table 15.1 Comparison of Restrictive Cardiomyopathy vs. Constrictive Pericarditis by Diastolic Indices Diastolic index
Restrictive cardiomyopathy
Constrictive pericarditis
Mitral inflow
No respiratory variation of mitral inflow
Inspiration ¼ decreased mitral inflow E wave, prolonged IVRT Expiration ¼ opposite changes Short DT Diastolic regurgitation
E/A ratio > 2 Short DT Diastolic regurgitation Pulmonary vein
Tricuspid inflow
Blunted systolic/diastolic (S/D) ratio (0.5), prominent and prolonged aortic regurgitation (AR) No respiratory variation D wave Mild respiratory variation of tricuspid inflow E wave E/A ratio > 2 TR peak velocity no significant respiratory change Short DT with inspiration Diastolic regurgitation
S/D ratio > 1 Inspiration ¼ decreased PV S and D Expiration ¼ opposite changes Inspiration ¼ increased inflow E wave, increased TR peak velocity Expiration ¼ opposite changes Short DT Diastolic regurgitation
Hepatic vein (HV)
Blunted S/D ratio, inspiratory increased reversals
Inspiration ¼ minimally increased HV, S and D Expiration ¼ decreased diastolic flow and increased reversals
Inferior vena cava
Plethoric
Plethoric
Color M-mode
Slow flow propagation
Rapid flow propagation (≥100 cm/s)
Mitral annular motion
Low velocity early filling
Normal or high velocity filling
123
N OTE S
124