🍋Right Atrium

When reporting:

  • RA size
  • Pressure
  • Normal variants – Eustachian valve/Chiari network.
  • Masses – tumour/thrombus.
  • Pacing wires/venous catheters/pipes etc.


Can eyeball in A4C – dilated if bigger than LA.

Measure minor (width) and major (length) axis.

Perform planimetry if good endocardial definition – calculates area but volume is not recommended due to lack of evidence of normal ranges.


Assume it is 10mmHg if no other information.

CVC is obviously more accurate.

If no CVC – estimated with IVC size in inspiration and expiration. Less accurate in ventilated patients.

In ventilated patients IVC diameter of <12mm appears to accurately identify patients with RAPs <10mmHg.

At low/normal RAP there is predominantly sistolic flow in hepatic veins.. As RAP rises there is reversal so velocity of the diastolic flow becomes greater than the velocity of systolic flow. This has been validated in ventilated patients.

If interatrial septum bulges towards LA in cardiac cycle this is consistent with raised RAP of >15mmHg.

Eustachian valve:

Embryological remnant where the IVC enters the RA.

In fetal life this directs oxygenated blood away from tricuspid valve towards the foramen ovale.

Can remain prominent and is a normal finding. Care needs to be taken not to mistake for mass/thrombus/vegetation.

No clinical significance.

Eustachian valve

Chiari network:

Fetal remnant – appears as a web-like structure extending into the RA with an attachment near the RA-IVC junction.

Present in about 2% of the population.

No clinical significance.

Some evidence that either remnant in combination with PFO may increase risk of paradoxical embolism.

Chiari network