Right atrial size calculator and measurement guide
Explore right atrial size measurements, acquisition guidance and the reference context supplied with the tool.
Method
Grade the selected RA measure against the 2025 ASE method-specific table; volume methods index to BSA
Use the measurement units shown below. Some fields apply only to a selected method or condition; follow the interactive tool’s method choices. The interactive tool keeps missing measurements incomplete and provides its method-specific results and reference context.
Measurements and acquisition
Measure
Enter the measured value in the displayed unit
- RA volume index · method of disks
- RA volume index · area–length
- RA major dimension
- RA minor dimension
- RA end-systolic area
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
RA volume mL
Enter the measured value in the displayed unit
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
Body surface area m²
Record the units, date and measurement source
- Use measured height and weight where feasible. Record the units, date and whether a value was reported or estimated.
- Fluid status and weight changes affect BSA. Document any substituted weight; do not silently replace measured weight with ideal or dry weight.
- Use the unit named by the field. BSA is in m²; height and weight can be converted in the Body surface area calculator. Keep the formula with serial indexed results.
RA major dimension cm
2D echo · inner-edge measurement
- Use the specified view and cardiac phase.
- Align the calipers perpendicular to the structure’s long axis.
- Measure inner edge to inner edge and avoid oblique foreshortening.
RA minor dimension cm
2D echo · inner-edge measurement
- Use the specified view and cardiac phase.
- Align the calipers perpendicular to the structure’s long axis.
- Measure inner edge to inner edge and avoid oblique foreshortening.
RA end-systolic area cm²
Enter the measured value in the displayed unit
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
Entered value
Enter the measured value in the displayed unit
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
Sources and method context
American Society of Echocardiography · 2025 · Guidelines for the Echocardiographic Assessment of the Right Heart in Adults and Special Considerations in Pulmonary Hypertension · RA acquisition, methods and Table 1 partitions: 2025 right-heart guideline pp. 2, 4, 6, and 10.
- RA measurement methods · ASE 2025 right-heart guideline · pp. 2, 6, 10
Dedicated RA-focused A4C. Single-plane method of disks is the preferred 2D volume when indexed to BSA; area–length is a different method and is not interchangeable. Linear dimensions and area are supporting measures.
- RA reference partitions · ASE 2025 right-heart guideline · Table 1 p. 4; key points p. 2
Method-specific RA dimension, area, MOD-volume, and area–length volume partitions. Area–length is a different table from method of disks.
Catalogue review status: Source mapped · clinical sign-off pending
These pages describe the educational tool. Interpret measurements with the complete clinical context and the method’s acquisition limitations.
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