Cardiac Tamponade Flashcards
What is a pericardial effusion?
Accumulation of fluid in pericardial sac (usually 10-50mL)
State some potential causes of a pericardial effusion
- Pericarditis
- Myocardial ruputre (surgical, stab wound, post MI etc..)
- Aortic dissection
- Malignancy
- TB (can cause pericarditis)
State some symptoms of a pericardial effusion
- Dyspnoea
- Chest pain
- Signs of local structures being compressed e.g.
- Phrenic nerve= hiccups
- Diaphragm= nausea
- Compressed left lower lobe= bronchial breathing over left lower lobe “Ewart’s sign”
State what you might find on examination of someone with pericardial effusion
- Muffled heart sounds
- Signs of cardiac tamponade (if this is developing):
- Tachycardia
- Hypotension
- Pulsus paradoxus
- Increased JVP
- Kussmauls sign
State what investigations you would do if you suspect cardiac tamponade
State what you might find on each
- CXR: enlarged, globular heart if effusion >300mL
- ECG: low voltage QRS and my have alternating QRS morphologies (QRS amplitude alternates
- ECHO: echo-free zone surrounding heart
Discuss the treatment of pericardial effusion
- Treat underlying cause
- May do pericardiocentesis for diagnostic reasons e.g. suspected bacterial pericarditis. Send fluid for culture, ZN stain/TB culture, cytology
- Can also give anti-inflammatories and gastro protection and observe
What is the main complication you need to look for in someone with pericardial effusion?
Cardiac tamponade (progression of pericardial effusion)
What is cardiac tamponade?
Cardiac tamponade is the accumulation of pericardial fluid, blood, pus, or air within the pericardial space that creates an increase in intra-pericardial pressure, restricting cardiac filling and decreasing cardiac output
What are the symptoms of cardiac tamponade?
- Dyspnoea
- Chest pain
- Abdo pain (secondary to hepatic congestion)
- Signs of local structures being compressed e.g.
- Phrenic nerve= hiccups
- Diaphragm= nausea
- Compressed left lower lobe= bronchial breathing over left lower lobe “Ewart’s sign”
What might you find on clinical examination of someone with cardiac tamponade?
- Tachycardia
- Hypotension
- Pulsus paradoxus
- Raised JVP
- Kussmaul’s sign
- Muffled heart sounds
What is pulsus paradoxus and explain why it occurs in cardiac tamponade?
- Idea that, when patient inspires, you can hear heart beat on auscultation but can’t feel the pulse
- See image for why it occurs
*NOTE: it’s normal for bp to drop ~10mmHg during inspiration. When inspire, increase lung volume decrease intrathoracic pressure. This decrease in pressure results in more blood returning to right side of heart hence more blood enters pulmonary vascualture. Also get increase in pulmonary vasculature volume hence get pooling of blood in pulmonary vasculature. Decreased return to left atrium & hence ventricle hence decrease SV and therefore decrease ~10mmHg on inspiration
What is Kussmaul’s sign and explain why it occurs in cardiac tamponade?
?
What triad is indicative of cardiac tamponade?
Beck’s triad:
- Falling BP
- Rising JVP
- Muffled heart sounds
State what investigations you would do if you suspect cardiac tamponade, include:
- Bedside
- Bloods
- Imaging
Bedside
- ECG: low voltage QRS and electrical alternans (amplitude of QRS complexes varying)
Bloods
- FBC: baseline
- ESR: inflammation
- Cardiac enzymes: may be raised in trauma or infarction and this can be a cause
Imaging
- ECHO: echo-free zone
- CXR: pericardium can hold 200ml of fluid before shows enlarged silhouette. Not very senstive or specific
- Cardaic catheterisation: will show equalisation of pressures in chambers
What ECG changes are characteristic of cardiac tamponade?
- Low voltage QRS
- Electrical alternans
- Sinus tachycardia
Pulsus paradoxus summary
