Echocardiographic Parameters
2D TTE was performed either during the index hospitalization or within three months of the indexed ischemic stroke. Studies were performed according to the guidelines from the American Society of Echocardiography (ASE)22, and reports were generated by cardiologists board-certified in echocardiography. Phasic LA function was quantified off-line using TOMTEC (Chicago, IL)23according to guidelines from the European Association of Cardiovascular Imaging (EACVI)/ASE Task Force24. The procedure entailed a careful selection of TTE images capturing optimal views of the left atrium (LA). Specifically, the LA-focused apical 4-chamber (A4-C) and 2-chamber (A2-C) views providing the clearest visualization were obtained. In cases where the A4-C view did not provide sufficient clarity, the A2-C view was used independently. After thorough assessment of multiple cardiac cycles, a single cardiac cycle presenting the best image quality was chosen. The LA endocardial border was manually traced from mitral annulus at one side, extrapolating across the pulmonary veins and atrial appendage orifices to the opposite side in the end-diastolic and end-systolic phases of a cardiac cycle (Figure 2). This generated average atrial strain curve with two peaks. LA reservoir strain was calculated by measuring the peak atrial longitudinal strain (PALS) at the end of ventricular systole, corresponding with the first peak. LA contractile strain was calculated by measuring the peak atrial contraction strain (PACS) at the onset of atrial contraction, corresponding with the second peak. Conduit (passive emptying) strain was calculated by the difference between the PALS and PACS12, 24 (Figure 2). The quality of wall tracking was recorded according to the number of walls appropriately tracked. Echocardiography analysis was blinded to stroke subtype and outcomes.