C. No Y descent on JVP – Explanation
In cardiac tamponade there is characteristically no Y descent on the JVP. The other four features
are seen in both cardiac tamponade and constrictive pericarditis
Cardiac tamponade
Features
- dyspnoea
- raised JVP, with an absent Y descent – this is due to the limited right ventricular filling
- tachycardia
- hypotension
- muffled heart sounds
- pulsus paradoxus
- Kussmaul’s sign (much debate about this)
- ECG: electrical alternans
The key differences between constrictive pericarditis and cardiac tamponade are summarised in the
table below:
| Cardiac tamponade | Constrictive pericarditis | |
| JVP | Absent Y descent | X + Y present |
| Pulsus paradoxus | Present | Absent |
| Kussmaul’s sign | Rare | Present |
| Characteristic features | Pericardial calcification on CXR |
A commonly used mnemonic to remember the absent Y descent in cardiac tamponade is
TAMponade = TAMpaX
