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. Methods: A single-center study was conducted, prospectively enrolling consecutive patients with secondary tricuspid regurgitation who underwent two- and three-dimensional echocardiography. Results: A total of 350 patients were enrolled (mean age, 75 ± 13 years; 65% women). Although patients with A-STR and V-STR presented similar degrees of secondary tricuspid regurgitation and comparable RA size, the ES RA/RV volume ratio was significantly larger in A-STR than in V-STR (1.75 [interquartile range, 1.35-2.45] vs 1.18 [interquartile range, 0.81-1.66], respectively; P < .001). On receiver operating characteristic analysis, the ES RA/RV ...