Assessing right atrial size in patients with tricuspid regurgitation: importance of the right ventricular-focused view.

Aims: To assess the accuracy of measuring the right atrial volume (RAV) using two-dimensional echocardiography (2DE) in a right ventricular focused (RVF) view compared to the conventional apical four-chamber (4Ch) view in patients with secondary tricuspid regurgitation (STR). We also compared the clinical correlates of the measures obtained using different methods.

Methods and results: The accuracy of RAV measurements obtained between 2DE-4Ch and RVF views in 384 patients with STR were compared using three-dimensional echocardiography (3DE) as a reference. We used the analysis of variance to test the differences among RAVs obtained from the different 2DE and 3DE acquisitions and the receiving operating characteristics (ROC) curves to evaluate the association with the composite endpoint of hospitalization for heart failure or death. Compared to 3DE, RAV was significantly more underestimated when measurements were obtained from 4Ch rather than RVF (-24 vs. -14%, respectively, P < 0.001 for both). RAV underestimation in 4Ch and RVF view was relatively larger in lower grades of STR (-28 vs. -17% in mild, -23 vs. -14% in moderate, and -19 vs. -11% in severe STR, P = 0.001), and in the atrial compared to ventricular (-28 vs. -22%; P = 0.002) STR. RAV measured by 3DE and RVF showed the highest area under the curve (AUC = 0.67 for 3DE vs. 0.64 for RVF, P = 0.05), while 4Ch was significantly less related to the outcomes (AUC: 0.61, P = 0.021 vs. 3DE RAV).

Conclusion: In patients with STR, the use of RVF view improved the accuracy of 2DE RAV measurement as compared to the conventional 4Ch-derived measurements.