Qlab workstation

Preoperative baseline characteristics including demographics, TTE findings, and hemodynamic data were collected. Epiq 7G or CVx (Philips Healthcare, Amsterdam, The Netherlands) were used for TTE.
Postoperative data, except for hemodynamic parameters, were collected the day after ASD closure. The mid-term follow-up data, including hemodynamic parameters, were collected 6 months after the intervention. Cardiovascular events including cardiac death or heart failure readmissions were counted for two years or until June 2023 following the index ASD closure, which was defined as day 0.
Additional echocardiographic analysis including LA peak systolic (LAs) strain was performed offline using QLAB workstation (Philips Healthcare, Amsterdam, The Netherlands) in a blinded manner to the study data. Researchers who measured LA strain were blinded to all clinical data at the time of data measurements. In sinus rhythm, the data were recorded in 3 consecutive heartbeats, and in atrial fibrillation, in 5 consecutive heartbeats. Global LA strain measurements were taken from 4 atrial walls from apical 4-chamber images and 2-chamber images at end-expiration and averaged over 3 consecutive cardiac cycles. Segments were excluded if signal quality was poor.

For each injection, the obtained image series were divided in time intervals of 20 seconds, starting when inflow of CA into the left ventricle was observed. From each time interval, the image with the highest and most homogeneous contrast enhancement was selected for further analysis using a Q-Lab workstation (Philips Healthcare, Best, The Netherlands). Among these images, experienced observers (n = 3), who were blinded to CA type and dose, visually selected the image with best potential for endocardial border delineation. This was done individually by each observer. The endocardial border delineation of the selected image was evaluated by the observers using a 6-segment model (see Figure 
1). Every segment was graded as 0 = not visible, 1 = weakly visible, or 2 = visible. Furthermore, the duration of clinically useful contrast enhancement was evaluated by the three observers visually (while still blinded to dose and CA type), and the mean time was calculated for each dose and injection.

Two-dimensional grayscale harmonic images were obtained in the left lateral decubitus position using a commercially available ultrasound system (EPIQ 7, Philips, Best, the Netherlands), equipped with a broadband (1–5 MHz) X5–1 transducer. All acquisitions and measurements were performed according to current guidelines [13 (link),14 (link)].
To optimize speckle-tracking echocardiography, apical images were obtained at a frame rate of 60 to 80 frames/s. Three consecutive cardiac cycles were acquired from all apical views. Subsequently, these cycles were transferred to a QLAB workstation (version 10.2, Philips, Best, the Netherlands) for off-line speckle-tracking analysis. The peak regional longitudinal strain was measured in 17 myocardial regions and a weighted mean was used to derive global longitudinal strain (GLS).