The right atrial area is measured by traced the outline of the RA cavity at end-systole (just before the tricuspid valve opens in diastole). Start with two points at either side of the tricuspid valve annulus, then trace the rest of the outline of the RA cavity
Tips:
This measurement is commonly done on a zoomed RA view in some echo labs – just make sure you can see the whole RA clearly in frame
The ASE guidelines on right atrial size offer the following guidelines on normal values: