BACKGROUND: Left atrial (LA) volumes and emptying fraction in the general population may address structural and functional aspects of atrial cardiomyopathy associated with long-term risk of ischemic stroke in the absence of atrial fibrillation or prior stroke. We investigated the association between LA volumes and function and ischemic stroke. 

METHODS AND RESULTS: In a community-based cohort, we measured LA minimal volume, LA maximal volume, and LA emptying fraction by transthoracic echocardiography. The primary end point was ischemic stroke. Participants with known atrial fibrillation or prior ischemic stroke were excluded, which resulted in 1866 participants. The mean age was 58±16 years, and 57% were women. During a median follow-up of 16.5 years (interquartile range: 11.4–16.8 years), 176 (9.4%) ischemic strokes occurred. In multivariable cause-specific regression models and competing risk models with death as a competing risk, LA emptying fraction was associated with ischemic stroke (hazard ratio [HR], 1.14 per 10% decrease [95% CI, 1.02–1.28]) and (subdistribution HR, 1.14 [95% CI, 1.01–1.29]). This association remained when adjusting for participants who developed atrial fibrillation during follow-up (HR, 1.12 per 10% decrease [95% CI, 1.00–1.26]). Indexed LA volumes were not associated with ischemic stroke in the same models. LA emptying fraction and indexed LA volumes were not associated with all-cause mortality. 

CONCLUSIONS: Lower LA emptying fraction measured by transthoracic echocardiography was associated with future ischemic stroke independently of incident atrial fibrillation. 

REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02993172.