Impaired Left Atrial Function linked to Incident Dementia

Electrocardiographic markers of atrial myopathy are associated with dementia has been reported in few studies, Atrial myopathy commonly characterized by alterations in left atrial (LA) function and size is associated with ischemic stroke, independent of atrial fibrillation (AF), but it is unclear whether 2-dimensional echocardiographic (2DE) defines LA function and size are associated with dementia.

A recent community based study by Wendy Wang, and team revealed that there were statistically significant associations between measures of lower LA function and incident dementia comparing the lowest vs highest quintile for LA reservoir strain, conduit strain, contractile strain, emptying fraction, and active emptying fraction. Measures of LA size were not significantly associated with incident dementia.

The study findings are published in JAMA Network.

Study examined the association of LA function and size with incident dementia, The Atherosclerosis Risk in Communities (ARIC) study is a community-based prospective cohort. An exploratory, retrospective analysis was conducted. Participants without prevalent AF and stroke and who had 2DEs in 2011-2013 were included and surveilled through December 31, 2019. The Dementia cases were identified using in-person and phone cognitive assessments, hospitalization codes, and death certificates. Cox proportional hazards models were used.

The results of the study were

• Total 4096 participants, 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.

• 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 for active emptying fraction, 1.43. LA passive emptying fraction was not significantly associated with dementia HR, 1.26 .

• Both measures were not significantly associated with dementia. These findings were robust to sensitivity analyses that excluded participants with incident AF or stroke.

Wang, and team concluded that "In this exploratory analysis of a US community-based cohort, several echocardiographic measures of lower LA function were significantly associated with an increased risk of subsequent dementia. Measures of LA size were not significantly associated with dementia risk. These findings suggest that impaired LA function may be a risk factor associated with dementia."

Reference: 10.1001/jama.2022.2518