LAUSR

Background: Accruing evidence suggests that changes in cardiac structure and function, irrespective of tachyarrhythmia, are responsible for thrombus formation. Although transthoracic echocardiogram (TTE) is frequently used for cardiovascular evaluation in ischemic stroke patients (IS), many cardiac features that could clarify stroke subtype are poorly characterized without optimal evaluation of the left atrium (LA). 2D speckle tracking echocardiography (STE) allows an accurate, reproducible, and detailed assessment of the LA cycle. Methods: IS with clinically indicated TTE provided consent. LA STE was quantified using a post processing wall motion tracking software per standard definitions. Strain/strain rate (Sr) curves for the 3 components of the LA cycle: 1) Reservoir (Global longitudinal Sr (Srmax)) 2) Conductive (Early LA Sr (Sre)) and 3) Contractile (Late LA Sr (Sra)) were evaluated. The association of embolic-appearing stroke (cardioembolic or cryptogenic; ES) with LA STE features (independent variables) was tested using logistic regression (OR (95%CI)) adjusted for covariates. Results: Participants (N=136) were 53-70yo, 57% female and 59% black. Incremental increases in Sra (worse LA contraction) were associated with >2 times greater odds of ES (2.47 (1.29-4.72)) and improvement in Smax (LA reservoir) was associated with decreased odds of ES when adjusting for demographics (0.98 (0.96-0.99)), but not in a fully adjusted model. Improvement in the corresponding emptying fractions was significantly associated with decreased odds of ES (aEF 0.93 (0.98-0.97) tEF 0.96 ( 0.93-0.99)). Conclusions: In this study the odds of ES was higher in those with worse LA contraction and decreased with improvement in LA reservoir with corresponding decreased odds of ES with improvement in emptying fractions. LA STE is an underutilized technology and may represent a promising tool for characterization of LA performance in patients with otherwise unexplained ES.