Right Atrial (RA) Area Index: Explanation and Clinical Context The RA Area Index is calculated by dividing the right atrial area (measured by echocardiography) by the patient’s body surface area (BSA), providing a standardized measurement to assess right atrial enlargement.
Normal RA area index is typically < 10.5 cm²/m². Values above this threshold indicate right atrial dilation, often associated with chronic pressure or volume overload due to conditions such as pulmonary hypertension, tricuspid regurgitation, or right ventricular dysfunction.
Clinically, RA enlargement is a marker of adverse outcomes in patients with pulmonary hypertension and right-sided heart disease. Monitoring RA area index helps in risk stratification, therapy adjustment, and prognosis evaluation.
Reference:
Lang RM, Badano LP, Mor-Avi V, et al. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015;28:1–39. doi:10.1016/j.echo.2014.10.003