Left Atrial Strain, Embolic Stroke of Undetermined Source, and Atrial
Fibrillation Detection
Abstract
Background: Atrial cardiopathy is a proposed mechanism of
embolic stroke of undetermined source (ESUS). Left atrial (LA) strain
may identify early atrial cardiopathy prior to structural changes. We
aim to study the associations between LA strain, ESUS, and atrial
fibrillation (AF) detection in ESUS. Methods: The study
population included patients with ESUS and non-cardioembolic (NCE)
stroke presenting to statewide stroke center between January 2016 and
June 2017 who underwent transthoracic echocardiography. Speckle tracking
echocardiography (STE) was used to measure the 3 phases of LA strain
(reservoir, conduit, and contractile). Binary logistic regression
analysis was performed to determine the associations between LA strain
and stroke subtype (ESUS vs. NCE) as well as follow-up detection of AF
in ESUS patients. Results: We identified 656 patients, 307 with
ESUS and 349 with NCE. In binary logistic regression, the lowest
tertiles of LA reservoir (adjusted OR 1.944, 95% CI 1.266-2.986, p =
0.002), contractile (aOR 1.568, 95% CI 1.035-2.374, p = 0.034), and
conduit strain (aOR 2.288, 95% CI 1.448-3.613, p = 0.001) were more
likely to be significantly associated with ESUS compared to NCE stroke.
Among all ESUS patients, the lowest tertiles of LA reservoir strain (OR
2.534, 95% CI 1.029-6.236, p = 0.043), contractile strain (OR 2.828,
95% CI 1.158-6.903, p = 0.022), and conduit strain (OR 2.614, 95% CI
1.003-6.815, p = 0.049) were significantly associated with subsequent
detection of AF. Conclusion: Reduced LA strain is associated
with ESUS occurrence and AF detection in ESUS patients. Therefore,
quantification of LA strain in ESUS patients may improve risk
stratification and guide secondary prevention strategies.