Abstract Body: Background: Left atrial myocardial function can be studied by measuring Left atrial (LA) strain using speckle tacking echocardiography. Decreased LA strain has been shown to increase thromboembolic risk. This dynamic measure of LA dysfunction may provide insight into echocardiographic factors associated with ischemic stroke despite therapeutic anticoagulation (AC) in patients with atrial fibrillation (AF).

Methods: This was a retrospective observational study on consecutive ischemic stroke patients with AF between June 2018 and December 2020 admitted to our institution. Patients were divided in two groups: those on AC and those off AC at the time of the stroke. We then performed Speckle tracking echocardiography using TOMTEC™ 2D strain analysis software to compare different measures of LA function including LA volume index (LAVI), LA Systolic Volume (LAESV), LA Diastolic Volume (LAEDV), LA Ejection Fraction (LAEF) in both groups.

Results: A total of 239 patients met the criteria and 178 pts underwent LA strain assessment. There were 34 patients in the on-AC group (Mean age: 78 years, SD 10) and 144 pts in the Off-AC group (Mean age: 79 years, SD 11.5). Mean LAVI was 42 ml in on-AC group (SD 14.5ml) vs. 44ml (SD 19 ml) in off-AC group (P value = 0.31). LAEF was significantly lower in the on-AC group (19%, SD 21.3%) compared to off-AC group (21% SD 18%), P value < 0.0001. LAESV was significantly lower in the on-AC group (67 ml [SD 28 ml] vs. 79 ml [SD 34 ml], P value = 0.035). LAEDF was also significantly lower in the on-AC group (51 ml [SD 27 ml] vs. 64 ml [SD 30 ml], P value = 0.015).

Conclusion: Patients with atrial fibrillation who experience an ischemic stroke despite therapeutic anticoagulation have significantly lower LAEF, LAESV, LAEDV on LA strain analysis using speckle echocardiography. This suggests that left atrial structural dysfunction plays a key role in AC failure and this tenchnique can identify such high risk patients. More studies are needed to identify potential treatment targets and individualized management plans for patients with these echocardiographic markers of atrial cardiopathy.