Abstract A076: Unmasking Atrial Cardiopathy: A Systematic Review and Meta-Analysis of Left Atrial Strain in Embolic Stroke of Undetermined Source

Background: Embolic stroke of undetermined source (ESUS) accounts for up to one-third of ischemic strokes, yet optimal secondary prevention remains uncertain due to heterogeneous underlying mechanisms. Atrial cardiopathy has emerged as a potential driver of embolic risk even in the absence of atrial fibrillation (AF). Left atrial (LA) strain, assessed by speckle-tracking echocardiography, is a novel noninvasive biomarker of atrial dysfunction that may improve risk stratification. Methods: We systematically searched PubMed, Embase, Scopus, and Cochrane through July 2025 for studies evaluating LA strain in ESUS. Eligible studies compared LA strain metrics in ESUS versus other ischemic stroke subtypes. Data extracted included study design, patient characteristics, and quantitative LA strain measures: reservoir (LASr), conduit (LAScd), and contractile (LASct). Pooled mean differences (MDs) with 95% confidence intervals (CIs) were estimated using a random-effects model. Heterogeneity was assessed. Results: Four studies (n = 834; ESUS = 413) met the inclusion criteria. Compared with non-cardioembolic ischemic stroke, ESUS was associated with significantly impaired LASr (MD −5.92%, 95% CI −8.82 to −3.02) and LAScd (MD −3.42%, 95% CI −6.21 to −0.64), with a trend toward lower LASct (MD −1.59%, 95% CI −3.62 to 0.45). Across cohorts, LASr and LAScd also differentiated ESUS from large-vessel occlusion stroke. Conclusions: This first meta-analysis focused on LA strain in ESUS demonstrates significant impairment of atrial mechanical function, particularly reservoir strain, reinforcing atrial cardiopathy as an AF-independent mechanism of embolic stroke. LA strain shows promise as a biomarker to refine risk stratification and guide future secondary prevention trials in ESUS.