The Pathophysiological Link between Right Atrial Remodeling and Functional Tricuspid Regurgitation in Patients with Atrial Fibrillation: A Three-Dimensional Echocardiography Study

Background: Atrial fibrillation (AF) itself may lead to functional tricuspid regurgitation (FTR) through tricuspid annulus (TA) dilation. However, the pathophysiological determinants of TA enlargement in AF patients remain to be clarified. The objectives of this study were (1) to compare the TA size and function in AF patients versus healthy subjects; (2) to identify the determinants of TA remodeling in patients with AF and FTR; and (3) to assess the relationships among right heart structures and severity of FTR in AF patients. Methods: Eighty-three consecutive patients with long-term persistent AF and FTR (61 ± 9.9 years, 67% women) were prospectively enrolled and compared with 83 sex and body surface area–matched healthy subjects. Heart chamber size and function and TA geometry were analyzed using three-dimensional echocardiography. Results: Among AF patients, 33%, 34%, and 33% had mild, moderate, and severe FTR, respectively. Right atrial (RA) dilation was detected in 93% of AF patients, while only 27% and 12% of them showed dilated or dysfunctional right ventricle (RV), respectively. End-diastolic TA area had the strongest correlation with the minimum volume of the RA (RAVmin r = 0.6981, P <.0001) but only mild correlation with RV end-diastolic volume and sex (r = 0.3405, P =.0019; r = 0.2914, P =.0075). At multivariable analysis, only RAVmin was independently associated with TA area in AF patients (r = 0.665, P <.0001). The RAVmin and TA area were the only predictors of FTR severity. Conclusions: In patients with AF, RA dilation seems to be more important than RV dilation to determine TA enlargement and subsequent FTR development. The RAVmin and TA area were directly correlated to FTR severity.