Background: Limited data exist to characterize novel measures of left atrial (LA) structure and function in older adults without prevalent heart failure (HF). Objectives: To assess reference range of LA measures, their associations with N-terminal pro-brain-natriuretic-peptide (NTproBNP) and the related risk for incident HF or death. Methods: We analyzed LA structure [LA maximal and minimal volume indexed by body surface area (LAViMax and LAViMin)] and function [LA emptying fraction, LA reservoir, conduit and contraction strain] in 4901 participants from the Atherosclerosis Risk in Communities (ARIC) study (mean age 75±5 years, 40% male and 19% black) without prevalent HF. We assessed gender-specific 10th and 90th percentile ARIC-based reference limits in 301 participants free of prevalent cardiovascular disease, and related LA measures to NTproBNP and incident HF or death (median follow-up of 5.5 years) in the whole ARIC cohort. Results: Approximately 20% of the overall population had LA abnormalities according to the ARIC-based reference limit. Each LA measure was associated with NTproBNP and, except for LAViMax, with incident HF or death after multivariable adjustment. Results were consistent in participants with normal LAViMax (p for interaction>0.05). LA measures were prognostic for both incident HFpEF or death and incident HFrEF or death. When added to HF risk factors and NTproBNP (baseline C-statistics=0.74) all LA measures, except for LAViMax, significantly enhanced the prognostic accuracy. Conclusion: Novel measures of LA structure and function, but not standard assessment by LAViMax, are associated with increased risk of incident HF or death regardless of measures of LV function and NTproBNP
