Abstract 13738: Longitudinal Changes and Remodeling in the Right Atrium: The Multi-ethnic Study of Atherosclerosis

Abstract

Introduction: The role of the right atrium (RA) in the pathogenesis and prediction of cardiovascular disease has been increasingly recognized, however the effects of aging on the RA remain unknown. In this longitudinal study we sought to describe the structural and functional changes in the RA over approximately ten years and explore their association with demographic and clinical risk factors. Methods: We included 1509 participants who had cardiovascular magnetic resonance at Exam 1 (2000-2002) and follow-up at Exam 5 (2009-2010) with adequate quality RA imaging at both timepoints. Quantification was performed using multimodality tissue tracking software, which has been extensively validated previously. Volumes were indexed to body-surface area. Adjusted multivariate linear regression used for analysis. Results: Participants were on average 58 years old at study onset, 54% female, 43% white, 14% Chinese American, 25% black, and 18% Hispanic. Over 10 years, RA indexed maximum and minimum volumes increased by 32% (8.8 mL/m2) and 37% (5.2 mL/m2) respectively. RA emptying fraction (EF) decreased by 1.3% and global strain trended towards a 0.7% decrease. Older age was associated with greater increases in volume but smaller decreases in function. Men had greater increase in volume and decrease in function, as did black and white races. Baseline obesity (BMI≥30), smoking, and diabetes status were all associated with greater decreases in function. Baseline use of ACE-inhibitors, lipid-lowering medications, and antihypertensives were not associated with larger or smaller changes in structure or function. Conclusions: In this large, diverse participant cohort, RA volumes substantially increased and function decreased over 10 years of follow-up. These differences were generally more prominent among men, older individuals, and white and black participants, and were further associated with baseline clinical risk factors.