USA: Findings from an exploratory analysis of a US community-based cohort suggest that impaired left atrial (LA) function may be a risk factor associated with dementia. The study was published in the Journal of the American Medical Association (JAMA).
"The results showed that several echocardiographic measures of lower LA function were significantly associated with an increased risk of subsequent dementia," Wendy Wang, University of Minnesota, Minneapolis, and colleagues wrote in their study. "The measure of LA size however was not significantly associated with the risk of dementia."

Atrial myopathy characterized by alterations in LA function and size, independent of atrial fibrillation (AF), is associated with ischemic stroke. Previous studies have shown electrocardiographic markers of atrial myopathy to be associated with dementia but there is no clarity on whether 2-dimensional echocardiographic (2DE)–defined LA function and size are associated with dementia. To get some clarity on the topic, Dr. Wang and colleagues aimed to examine the association of LA function and size with incident dementia. The Atherosclerosis Risk in Communities (ARIC) study is a community-based prospective cohort.
For this purpose, the researchers conducted an exploratory, retrospective analysis. . ARIC centers are located in Forsyth County, North Carolina; Jackson, Mississippi; Washington County, Maryland; and suburban Minneapolis, Minnesota. Visit 5 (2011-2013) served as the baseline for this analysis. It included participants without prevalent AF and stroke and who had 2DEs in 2011-2013 and was surveilled through December 31, 2019.
Based on the study, the researchers reported the following findings:
Among 4096 participants (mean age, 75 years; 60% women; 22% Black individuals), 531 dementia cases were ascertained over a median follow-up of 6 years.
Dementia incidence for the lowest LA quintile was 4.80 for reservoir strain, 3.94 for conduit strain, 3.29 for contractile strain, 4.20 for emptying fraction, 3.67 for passive emptying fraction, and 3.27 for active emptying fraction per 100 person-years.
After full-model adjustments, there were statistically significant associations between measures of LA function and dementia; the hazard ratios (HRs) from the lowest vs highest quintile for reservoir strain were 1.98; for conduit strain, 1.50; for contractile strain, 1.57; for emptying fraction, 1.87; and for active emptying fraction, 1.43.
LA passive emptying fraction was not significantly associated with dementia (HR, 1.26).
Dementia incidence for the highest LA maximal volume index quintile was 3.18 per 100 person-years (HR for highest vs lowest quintile, 0.77) and for the highest minimal volume index quintile was 3.50 per 100 person-years (HR for the highest vs lowest quintile, 0.95).
Both measures were not significantly associated with dementia.
These findings were robust to sensitivity analyses that excluded participants with incident AF or stroke.
"Given the exploratory nature of the study findings, prospective validation in other cohorts is clearly necessary," wrote the authors. "In addition to identifying the precise biomarkers of atrial myopathy, randomized clinical trials testing treatments in patients with atrial myopathy could further establish a causal effect on dementia."
Reference:
Wang W, Zhang MJ, Inciardi RM, et al. Association of Echocardiographic Measures of Left Atrial Function and Size With Incident Dementia. JAMA. 2022;327(12):1138–1148. doi:10.1001/jama.2022.2518
KEYWORDS: JAMA, impaired LA function ,dementia, left atrial function, echocardiographic measures, atrial myopathy, cardiovascular outcomes, stroke, Wendy Wang