Cardiac Tamponade – Echocardiography Findings
Cardiac Tamponade – Echocardiography Findings
Echocardiography is the gold standard for diagnosing cardiac tamponade. It helps detect the presence of pericardial effusion, assess hemodynamic impact, and confirm tamponade physiology.
Key Echocardiographic Findings in Cardiac Tamponade
1. Pericardial Effusion
- Echo-free space surrounding the heart (best seen in subcostal and parasternal views).
- Can be circumferential or loculated.
- Large effusions (>20 mm in diastole) are more likely to cause tamponade, but tamponade can occur with smaller effusions if accumulation is rapid.
2. Chamber Collapse
- Right atrial systolic collapse
- Highly sensitive but not specific.
- Occurs in early systole, when RA pressure is lowest.
- Collapse lasting >1/3 of the cardiac cycle strongly suggests tamponade.
- Right ventricular diastolic collapse
- More specific for tamponade.
- Seen in early diastole when RV pressure is lowest.
- Distinguishes tamponade from simple effusion.
3. Respiratory Variation in Doppler Flows
- Mitral inflow (E-wave) decreases >25% during inspiration.
- Tricuspid inflow increases >40% during inspiration.
- Reflects exaggerated ventricular interdependence due to pericardial constraint.
- Equivalent to pulsus paradoxus on echo.
4. Inferior Vena Cava (IVC) Plethora
- Dilated IVC (>2.1 cm) with minimal inspiratory collapse (<50%).
- Indicates elevated right atrial pressure.
- Seen consistently in tamponade.
5. Septal Motion Abnormalities
- Interventricular septal bounce or shift with respiration (towards LV in inspiration, towards RV in expiration).
- Represents ventricular interdependence.
Summary Table
| Echo Finding | Timing | Significance |
|---|---|---|
| RA systolic collapse | Early systole | Sensitive sign of tamponade |
| RV diastolic collapse | Early diastole | Specific sign of tamponade |
| Respiratory Doppler variation | Mitral ↓ >25%, Tricuspid ↑ >40% | Hemodynamic compromise |
| IVC plethora | Dilated, no collapse | ↑ RA pressure |
| Large pericardial effusion | Any time | Predisposes to tamponade |
| Septal shift | With respiration | Ventricular interdependence |
✅ Take-home:
On echocardiography, the hallmark of cardiac tamponade is right-sided chamber collapse (RA systolic, RV diastolic) with exaggerated respiratory variation in ventricular filling and IVC plethora.
1. Which echocardiographic finding is most specific for cardiac tamponade?
Right ventricular diastolic collapse
Right atrial systolic collapse
Dilated inferior vena cava
Large pericardial effusion
Right ventricular diastolic collapse is the most specific echocardiographic sign of tamponade.
2. Right atrial systolic collapse in tamponade occurs because:
RA pressure is highest in systole
RA pressure is lowest in systole
RV pressure exceeds RA pressure in diastole
IVC inflow is blocked
Right atrial collapse occurs in early systole when RA pressure is lowest, making it vulnerable to external compression.
3. Which Doppler finding supports tamponade physiology?
Mitral inflow E-wave decreases >25% during inspiration
Tricuspid inflow decreases in inspiration
Aortic flow increases >50% in expiration
Pulmonary vein systolic reversal
Exaggerated respiratory variation in mitral and tricuspid inflows is a hallmark of tamponade.
4. Inferior vena cava plethora in tamponade means:
IVC diameter < 1.5 cm with full collapse
IVC diameter 1.5–2.0 cm with 50% collapse
IVC diameter > 2.1 cm with <50% inspiratory collapse
IVC shows complete collapse on inspiration
IVC dilatation with poor inspiratory collapse reflects raised right atrial pressure in tamponade.
5. Which is the earliest echocardiographic sign of tamponade?
Right atrial systolic collapse
Right ventricular diastolic collapse
Respiratory variation in Doppler flows
Septal shift
Right atrial collapse in systole is often the earliest detectable echo sign of tamponade.
6. Right ventricular collapse in tamponade is best identified in:
Parasternal long-axis view
Apical four-chamber or subcostal view
Suprasternal view
Parasternal short-axis at aortic level
RV diastolic collapse is best seen in apical four-chamber or subcostal views.
7. In tamponade, interventricular septal shift is due to:
Conduction block
Exaggerated ventricular interdependence
Reduced systemic vascular resistance
RV outflow obstruction
The septum shifts because filling of one ventricle impedes the other due to pericardial constraint.
8. Pulsus paradoxus on echo corresponds to:
Decrease in LV outflow in expiration
Respiratory variation in mitral and tricuspid inflow velocities
Right atrial collapse in systole
IVC collapse during inspiration
Pulsus paradoxus is mirrored on echo by exaggerated respiratory variation in Doppler inflows.
9. A large pericardial effusion without chamber collapse suggests:
Overt tamponade
Severe hemodynamic compromise
Effusion without tamponade physiology
Constrictive pericarditis
Tamponade is diagnosed by hemodynamic compromise, not just the size of effusion.
10. In tamponade, which Doppler change occurs across tricuspid valve in inspiration?
Increase in flow >40%
Decrease in flow >25%
No change
Complete cessation of flow
Tricuspid inflow increases significantly during inspiration in tamponade.
11. Collapse of which chamber is more sensitive but less specific for tamponade?
Right atrium
Right ventricle
Left ventricle
Left atrium
RA systolic collapse is an early, sensitive but less specific finding in tamponade.
12. Which left-sided chamber collapse is rarely seen but indicates severe tamponade?
Right atrium
Right ventricle
Left atrium
Coronary sinus
Left atrial collapse is rare but when present suggests severe tamponade.
13. In tamponade, left ventricular filling is most reduced during:
Inspiration
Expiration
Both phases equally
Unrelated to respiration
LV filling decreases during inspiration due to enhanced RV filling and septal shift.
14. Which echo feature best distinguishes tamponade from constrictive pericarditis?
Chamber collapse
IVC plethora
Respiratory variation in mitral inflow
Dilated hepatic veins
Chamber collapse (RA systolic, RV diastolic) is a hallmark of tamponade and not seen in constriction.
15. Which of the following supports tamponade diagnosis?
Small effusion with no collapse
Effusion with RA systolic and RV diastolic collapse
Dilated coronary sinus
Mild IVC dilation with full collapse
The combination of RA systolic and RV diastolic collapse confirms tamponade physiology.
16. Exaggerated respiratory variation in Doppler flows in tamponade reflects:
Increased preload
Decreased afterload
Ventricular interdependence
Mitral regurgitation
Tamponade causes abnormal ventricular interdependence leading to exaggerated Doppler variation.
17. Which of the following is least reliable for tamponade diagnosis?
RA systolic collapse
RV diastolic collapse
Size of pericardial effusion
Effusion size alone is not diagnostic; small effusions can cause tamponade if rapid.
18. Which cardiac cycle phase is best to detect RV collapse in tamponade?
Late systole
Early diastole
Mid systole
End diastole
RV diastolic collapse occurs in early diastole when RV pressure is lowest.
19. Which finding indicates severe hemodynamic compromise in tamponade?
Left atrial collapse
Mild RA collapse
Small effusion
IVC collapse with inspiration
Left atrial collapse is rare but strongly associated with severe tamponade.
20. Which echo view is most useful to demonstrate pericardial effusion in tamponade?
Suprasternal
Subcostal view
Apical 2-chamber
Parasternal short-axis at papillary level
The subcostal view provides an excellent window for detecting effusion and assessing RA/RV collapse.
| Point | Key Feature | Clinical Importance |
|---|---|---|
| 1 | Pericardial effusion | Primary finding, may be circumferential or loculated |
| 2 | RA systolic collapse | Earliest sign, sensitive but less specific |
| 3 | RV diastolic collapse | Most specific echo sign of tamponade |
| 4 | Duration of RA collapse | >1/3 of cardiac cycle → strongly suggests tamponade |
| 5 | Left atrial collapse | Rare, indicates severe tamponade |
| 6 | LV collapse | Very rare, in advanced tamponade |
| 7 | Doppler – mitral inflow | Inspiratory ↓ >25% |
| 8 | Doppler – tricuspid inflow | Inspiratory ↑ >40% |
| 9 | Doppler – pulsus paradoxus | Reflected as exaggerated inflow variations |
| 10 | IVC plethora | IVC >2.1 cm, <50% collapse on inspiration |
| 11 | Hepatic vein Doppler | Expiratory diastolic flow reversal |
| 12 | Septal shift | Interventricular dependence → septal bounce |
| 13 | Subcostal view | Best for detecting effusion and chamber collapse |
| 14 | Apical 4-chamber view | Excellent for RV diastolic collapse |
| 15 | Parasternal long-axis | Useful for effusion size assessment |
| 16 | Small effusion tamponade | Rapid accumulation can cause tamponade even if small |
| 17 | Large effusion without tamponade | Seen in slow accumulation (chronic pericarditis, malignancy) |
| 18 | Constriction vs tamponade | Collapse favors tamponade, not constriction |
| 19 | Echo Doppler hallmark | Exaggerated respiratory variation in inflows |
| 20 | Integration | Diagnosis = effusion + collapse + Doppler changes + IVC plethora |
10 Short Q&A Block: Cardiac Tamponade Echocardiography
Q1. What is the earliest echocardiographic sign of tamponade?
👉 Right atrial systolic collapse.
Q2. Which chamber collapse is most specific for tamponade?
👉 Right ventricular diastolic collapse.
Q3. What does RA collapse lasting >1/3 of the cardiac cycle suggest?
👉 Strongly diagnostic of tamponade.
Q4. What Doppler change is seen across mitral valve in tamponade?
👉 Inspiratory decrease in inflow velocity by >25%.
Q5. What Doppler change is seen across tricuspid valve in tamponade?
👉 Inspiratory increase in inflow velocity by >40%.
Q6. How does tamponade affect the IVC?
👉 IVC >2.1 cm with <50% inspiratory collapse (plethora).
Q7. What is the echocardiographic equivalent of pulsus paradoxus?
👉 Exaggerated respiratory variation in ventricular inflows.
Q8. Which view is best for detecting pericardial effusion and RA collapse?
👉 Subcostal view.
Q9. Which rare echo finding indicates severe tamponade?
👉 Left atrial collapse.
Q10. How to differentiate tamponade from constriction on echo?
👉 Tamponade shows chamber collapse; constriction does not.
