Abstract 80: Left Atrial Structural and Functional Parameters in Ischemic Stroke Patients Show Differences in Cardioembolic versus Embolic Strokes of Unknown Source (ESUS) and Other Determined Causes: Rethinking Whether ESUS Patients Should be Treated as Cardioembolic Equivalents

Background: The role of anticoagulation in patients with embolic strokes of unknown source (ESUS) remains controversial. Left atrial (LA) structural and functional parameters on transthoracic echocardiography (TTE) may predict ESUS patients who are likely to develop subsequent paroxysmal atrial fibrillation (PAF). Hypothesis: LA parameters in ESUS patients will be similar to cardioembolic (CE) stroke patients and different from patients with strokes due to other determined cause (ODC). Methods: Patients admitted to a stroke center from June 1 to November 30, 2015 with acute ischemic stroke were included in this analysis. Baseline characteristics and results of inpatient diagnostic workup including neuroimaging, echocardiography, and cardiac telemetry were reviewed retrospectively to classify patients into three subtypes: CE, ODC or ESUS. LA diameter, LA volume index (LAVI), mitral valve early (MV E) and late filling peak (MV Peak A) velocities were compared between the 3 subtypes. Results: Of 131 patients (mean age 67 ± 16, 47% female, 45% white), 35 (27%) were classified as CE, 62 (47%) ODC and 34 (26%) ESUS. Baseline characteristics were similar between groups except that ODC patients were less likely to be female than CE and ESUS patients (p=0.05). LAVI, MV E and MV Peak A were all significantly different in CE compared with ODC and ESUS patients (p Conclusions: LA structural and functional parameters among CE patients in our cohort were significantly different from those of ESUS and ODC patients, suggesting that ESUS patients may have lower risk of AF (and therefore lower likelihood of benefit from preemptive anticoagulation). Our study suggests that ESUS patients may benefit from long-term cardiac monitoring prior to initiation of anticoagulation therapy.