Assessment of Pericardial effusion

Text and images Genevieve Carbonatto

Pericardial effusions are commonplace. A pericardial effusion is not synonomous with pericardial tamponade. Pericardial tamponade is a medical emergency characterised by shock and associated with a number of clinical criteria including Becks triad (hypotension, decreased heart sounds, elevated JVP) pulsus paradoxus ( > 12 mmHg drop in BP on inspiration), tachycardia and tachypnea.

To properly describe an effusion you need to

  1. Assess whether it is circumferential or loculated. To do this you want to assess the effusion in as many windows as possible , the PLAX, The PSAX, the 4 chamber and the subcostal windows
  2. Quantify the effusion. This is done at the end of diastole by measuring between the 2 layers of the pericardium. You want to measure the biggest area. The effusion can either be 1. Trivial (only seen in systole) 2. small (<10mm) 3. Moderate (between 10 and 20mm) or 4. Severe  (>20mm)
  3. Descibe the fluid appearance. Anechoic (serous/fresh blood – not coagulated). hypoechoic (pus/partially coagulated blood), hyperechoic coagulated blood)
  4. Analyse for Haemodynamic compromise . RA, RV collapse, swinging heart , dilated IVC

Quantifying the effusion:

Parasternal short axis (PSAX) 2.35 cm

Describing the effusion

Anechoic effusion

Hyperechoic. This patient has an aortic dissection. You can see the coagulated blood coming into the pericardial space in systole and then moving out in diastole

Densely hyperechoic. This is coagulated blood from a knife wound to the LV causing blood to leak into the pericardium

Here we are at the apex of the heart and the pericardium is dense with fibrin strands

Fibrin strands in pericardium

Analysing for haemodynamic compromise

The following are the features we would be looking for which indicate haemodynamic compromise using 2D ECHO only. Remember that these features may be present but the patient may not have cardiac tamponade. Alternatively these features may not be present and the patient may have cardiac tamponade  if right ventricular diastolic pressures are elevated at baseline such as in pulmonary hypertension, positive pressure ventilation, severe LV failure or other congenital cardiac problems

  1. RA wall collapse – in early systole or late diastole. If more than 1/3 of the cardiac cycle then this is almost 100% specific and sensitive for clinical cardiac tamponade
  2.  RV wall collapse – in diastole. First only in expiration then throughout the cardiac cycle. The longer the indentation of the free wall, the more significant the severity of the haemodynamic compromise
  3.  LA collapse – usually seen with RA collapse. Not common
  4.  LV wall collapse – unusual – seen in patients with severe pulmonary hypertension
  5.  Swinging heart
  6. IVC  is fixed and dilated in cardiac tamponade, unless the patient is severely dehydrated. This has been termed “low pressure cardiac tamponade” and BP can be improved with iv fluids.

RA wall collapse and RV wall collapse in patient with a very large effusion. The free RV and RA walls are both collapsing and at different times of the cardiac cycle. The RA in late diastole, early systole RV collapse in diastole

Swinging heart

Fixed dilated IVC

Teaching point: Seeing a pericardial effusion is easy using ultrasound. Being able to descibe it to a cardiology team is important. Avoid using the term ” pericardial tamponade”  unless the patient is in shock and  there are real echo features suggestive of tamponade. The best way to descibe an effusion is by describing it systematically along with any haemodynamic features on echo suggestive of  haemodynamic compromise.

For example: “I have a haemodynamically stable patient with a 1.2 cm circumferential and anechoic  pericardial effusion . On ECHO there is  RA collapse and no RV collapse. “



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