A child presents with failure to thrive to pediatrics OPD. The doctor counseled the parents about improving nutrition of child , to which mother strongly asseed that they have ensured everything is perfect from their side especially nutrition, but to no avail. Then doctor requested for few investigations. What is the diagnosis?

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.