Left Atrial Myopathy Associated with Mitral Annular Calcification: The Atherosclerosis Risk in Communities (ARIC) Study

Background: Left atrial (LA) myopathy and mitral annular calcification (MAC) are increasingly prevalent in the older adults. Limited data exist on the association between impaired LA function and MAC in this population. Objectives: This study aimed to determine the association between LA function and the prevalence of MAC. Methods: Participants of the Atherosclerosis Risk in Communities (ARIC) study who underwent echocardiography at Visit 5 and non-contrast cardiac computed tomography (CT) at Visit 7 (2018-19) were included. LA function, including reservoir strain, conduit strain, and contraction strain was measured from two-dimensional echocardiography. The prevalence of MAC was assessed from cardiac CT. Multivariable logistic regression was used to assess the association between LA function and MAC. Results: Among 1,877 participants (mean±SD age 74±4 years, 62% women, and 20% Black), 900 (48%) had MAC. After full-model adjustments, both reservoir strain and conduit strain were significantly associated with presence of MAC (Prevalence Ratio(PR): 1.22; 95% CI: 1.08 – 1.39, and PR: 1.19; 95% CI: 1.05 – 1.35, respectively for lowest vs. highest tertile). Contraction strain was not significantly associated with MAC (Table). Results were consistent across age, sex, race, atrial fibrillation status, and LA size subgroups (p for interactions > 0.05). Sensitivity analyses excluding participants with baseline at risk for (stage A, including MAC) or established (stage B and above) mitral regurgitation yielded consistent findings. Conclusions: Impaired LA function (reservoir and conduit strain), but not contraction strain, is associated with higher prevalence of MAC in a community-based cohort of older adults. These findings suggest a potential pathophysiological link between LA function and calcification of the mitral apparatus.