Secundum-type ASD is the most prevalent congenital heart defect in adults, affecting approximately 7% of this population. Symptoms typically manifest in the third or fourth decade of life and may include exertional dyspnea, palpitations, chest pain, cyanosis, and, in rare cases, systemic thromboembolism. Patients are considered candidates for ASD closure if the left-to-right shunt ratio during RHC is ≥1.5 or if there is any indication of right ventricular volume overload. For those with elevated pulmonary vascular resistance, this should be less than one-third of the systemic vascular resistance, and pulmonary pressure must be below 50% of systemic pressure. Currently, the preferred method for closure is the transcatheter approach, provided that TEE shows the defect is suitable with adequate surrounding rims and structures. The success rate for this procedure exceeds 95%. Long-term outcomes for these patients are comparable to those of surgical closure, with fewer complications. Regular follow-up with echocardiography is essential to assess for any residual shunt and its potential, albeit rare, catastrophic complications.