Utility of the Ratio Between the Size of the Right Atrium and the Right Ventricle at End-Systole to Diagnose Atrial Secondary Tricuspid Regurgitation.

Background: In the multiparametric framework for diagnosing atrial secondary tricuspid regurgitation (A-STR), an end-systolic (ES) right atrial (RA)-to-right ventricular (RV) volume or area ratio ≥1.5 supports the diagnosis of A-STR over the ventricular secondary tricuspid regurgitation phenotype (V-STR). However, this threshold value has never been tested.