Atrial septal defect is one of the most common congenital heart diseases in adults. The defect often leads to volume overload in the right heart coupled with the potential risk of right heart failure and pulmonary arterial hypertension. These conditions lead to worsening in quality of life, decrease in physical capacity, and even to fatal outcomes. The main strategy for treatment of atrial septal defect is a transcatheter or surgical closure of the defect, but in patients with severe pulmonary arterial hypertension, it is recommended to manage pulmonary arterial hypertension and after that treat the defect invasively. This strategy is called “treat and repair” strategy. We present an illustrative case report of management and treatment of atrial septal defect, complicated with severe pulmonary arterial hypertension. In this case, surgical closure of the defect was contraindicated because of the high pulmonary vascular resistance. Therefore, the “treat and repair” strategy was approached. After specific medical treatment of pulmonary arterial hypertension, surgical closure of the defect was chosen and proven successful.