Assessment

1) Is there a pericardial effusion?

A pericardial effusion forms an anechoic area around the heart.

Remember, not all pericardial effusions cause tamponade. The amount of fluid and how quickly it accumulates are both important factors. However as a general rule, effusions greater than 2cm are considered large and likely to cause tamponade. The earliest and most sensitive finding for tamponade is the diastolic collapse of the right atrium (RA), followed by the RV. 

This PLAX view shows a massive pericardial effusion and RV collapse in diastole.

Case courtesy of Dr David Carroll, radiopaedia.org

Is the LV contracting normally?

In a patient with normal cardiac function, the walls of the LV should contract equally towards the middle of the ventricle. 
This PLAX view shows globally reduced contractility of the LV. The LV should contract > 30% in systole at the level of the papillary muscles. Hypokinesia may be due to infarction, myopathy or secondary to systemic conditions such as sepsis or toxins.

Case courtesy of Dr David Carroll, radiopaedia.org

Reduced movement (hypokinesia) may be limited to certain areas of the ventricle, suggesting localised ischaemia or damage. 

Conversely, if the walls of the ventricles contract > 90% or touch each other at the end of systole, it suggests a hyperdynamic circulation and may indicate hypovolaemia, haemorrhage or sepsis.

Is the RV acutely dilated?

As a rule of thumb, the normal ratio of RV to  LV is < 0.6. 

There are many causes of RV enlargement, but in the setting of acute shock, consider pulmonary embolism (PE) and right ventricle infarct. 

Other features of acute RV overload are:

The D sign

The D sign is seen on the PSAX view. The LV looks like a D instead of its usual round shape, due to paradoxical flattening of the interventricular septum in systole, when the RV pressure exceeds that of the LV.
This PSAX view shows the D sign in a patient with massive PE.

Case courtesy of Dr David Carroll, radiopaedia.org

McConnells sign

This is seen in the A4C view. McConnells sign is akinesia of the mid-section of the lateral wall of the RV, with normal or hyperkinetic movement of the apex. This is highly suggestive (in the correct clinical picture) for massive PE.  

This A4C view shows RV dilatation and denting in the hyperactive apex of the RV (McConnells sign).

Case courtesy of Allam Harfoush, radiopaedia.org

Clot in-transit

The presence of a clot in-transit suggests emboli are likely to pass to the lungs imminently which may cause massive PE and collapse. 
This A4C view shows a dilated RA with mobile echogenic material in a patient with chest pain and acute shortness of breath.

Image courtesy of Dr William Scheels: thepocusatlas.com

Pitfall

Patients with chronic pulmonary hypertension will have a dilated RA on cardiac ultrasound, so POCUS findings must be applied in the right context. One way to differentiate chronic pulmonary hypertension from acute RV overload is that in chronic pulmonary hypertension, the LV takes a D shape even in diastole.

There are more advanced assessments for right heart dysfunction inclusing TAPSE, and the 60/60 sign, but these are beyond the scope of RUSH protocol.

Learning bite

The pump part of the RUSH protocol looks at three important questions:

• Is there a pericardial effusion?
• Is the left ventricle contracting normally?
• Is the right ventricle acutely dilated?