Figure 2: Transthoracic echocardiography (a-d) showing ostium secundum atrial septal defect (red arrow) in the subcostal view (a) and apical four-chamber view (b); modified short-axis view demonstrating 1.8 cm × 1.5 mm clot (yellow arrow) in the left atrial appendage (c) and dilated main and branch pulmonary arteries (d); Transesophageal echocardiography (e and f) in color-compare mode showing the membrane inside the left atrium (purple arrow) and ostium secundum atrial septal defect (red arrow) in four-chamber (e) and short-axis view (f).