Echocardiographic findings in secundum atrial septal defect. Two-dimensional echocardiogram (apical 4-chamber view) shows a moderate-sized secundum ASD. A child with an ostium secundum ASD is most often asymptomatic; the lesion is often discovered inadveently during physical examination as conveyed in the above question's clinical history. The physical findings of an ASD are subtle and require careful examination of the hea, especially the hea sounds. Characteristic finding: 2nd hea sound is widely split and fixed in its splitting during all phases of respiration.