Typical cardiac murmur ECG and X-ray findings may suggest the presence of an atrial septal defect. An echocardiogram can confirm the diagnosis, and it should be differentiated from conditions such as anomalous pulmonary venous return, pulmonary valve stenosis, and small ventricular septal defects. For the treatment of atrial septal defects, in adult patients, if echocardiographic evidence of increased right ventricular volume load is present, the defect should be closed as soon as possible. Treatment options include interventional and open-heart surgical procedures. Before the implementation of interventional surgeries, all cases of simple atrial septal defects that have caused hemodynamic changes, with signs of increased pulmonary blood flow, enlargement of the atria and ventricles, and corresponding ECG findings, should undergo surgical treatment. In older patients with severe pulmonary hypertension, surgical treatment should be approached with caution.