Recent viral infection. Central pleuritic chest pain, eased by sitting forward. Reduced exercise tolerance.
This is a single subcostal cardiac view.
A moderate pericardial effusion is seen both anterior to the right ventricle and behind the left ventricle.
The see-saw rocking motion involving the right ventricular and right atrial walls indicates there is likely to be some pressure effect imparted by the pericardial effusion on right sided filling.
Tamponade is often a clinical diagnosis. A patient with hypotension, distended neck veins (raised JVP) and muffled heart sounds - Beck's triad may well have tamponade. Sadly Beck's triad is neither very sensitive nor specific.
A clinical suspicion associated with echocardiographic findings of a pericardial effusion increase the liklihood markedly.
There are a number of echocardiographic signs of tamponade. Important notes follow:
1. It is the rate of accumulation rather than the size that causes tamponade. Chronic effusions can reach very large sizes without causing pressure effects, and conversely relatively small acute effusions can exert their effects early.
Effusion size on Echocardiography (1)
- Small effusion: <0.5cm (roughly corresponds to <100cc)
- Moderate effusion: 0.5cm-2cm (roughly corresponds to 100-500cc)
- Large effusion: >2.0 cm (roughly corresponds to >500cc)
2. Effusions may be echo free, however it is not uncommon for them to contain echogenic debris (fibrin, blood, etc)
3. Right atrial systolic collapse is followed by right ventricular diastolic collapse (hence the see-saw appearance on echo).
4. A distended IVC with no respiratory variation is typical.
5. More specific findings rely on measuring flow velocities through the mitral valve during the respiratory cycle. Increased variation occurs with tamponade. Detailed discussion is beyond the scope of this article.
6. Pericardial and epicardial fat pads may be misinterpreted as fluid.
7. Haemopericardium may clot acutely and does not necessary appear as an echo free effusion.