Surgically
This procedure is done through open heart surgery (sternotomy or thoracotomy) using an ECC where the heart is stopped to allow a system of special cannulas to be placed. The hole is closed by a direct suture (sewing) if the hole is small enough or if the hole is larger, suturing (sewing) a small patch of pericardium (heart tissue or skin) or fabric to close the hole.To increase quality life following ASD procedures/surgeries, patients should have a physical exam and ECG every 3, 6, and 12 months with their cardiologist. For many patients with secundum ASD closure repair, they can return to their normal activities unless their procedure was heart catheterization which in this case they should rest for a few days. All patients should remain on blood thinner medication for at least 6 months and up to a year unless the patient had a stroke in which they would always be on blood thinners. Patients with coronary artery disease or pulmonary hypertension will take additional medicines described by their physician. For patients who had heart surgery to repair the defect or received a transcatheter closure device, they will need to take some form of antibiotics to prevent infections such as endocarditis for at least 6 months following the procedure.Success with ASD closure is very high, 96% for percutaneous procedures and 100% of ASD surgeries as found by one research group.
Then blood pass to right ventricle this will increase pulmonary artery pressure  Due to the incorrect blood flow, symptoms such as fatigue (from decreased systemic blood flow), palpitations (from blood flowing from left atria to right atria), weight gain, edema, right upper chest pain (all caused from the left to right atria blood flow), and paroxysmal nocturnal dyspnea (shortness of breath during sleep), orthopnea (difficulty in breathing while lying down), and hemoptysis or coughing up blood (all caused by small ASD that cause blood flow from left to right atria). Atrial Septal Defect Ostium secundum
During the more common form of Lutembachers syndrome, ASD Ostium secundum, a hole will form in the flap of tissue (septum primum) that should close between the two atria after birth. With the onset of a hole created in the tissue flap that closes the larger hole between the left and right atrium, blood can again flow from the left atrium to the right. Ostium secundum causes many of the same symptoms seen in ASD primum. With either type of ASD, blood will flow from the right atrium skipping the right ventricle (or very little flowing into the ventricle) and instead flow to the left atrium introducing the possibility of blood lacking oxygen to go the rest of the body. Sometimes, the direction of blood flow is largely determined by the left and right ventricle ability to squeeze (contract) and relax (compliance).Apart from congential or birth defects causing ASD, ASD is thought to be also acquired.