Atrial septal defect is the most common congenital cardiac malformation, which is an abnormality of the primitive atrial septum during embryonic development, leaving a gap between the left and right atria. It can occur alone or in conjunction with other types of cardiovascular malformations, and is more common in females, with a male to female ratio of approximately 1:3. It can cause corresponding hemodynamic abnormalities due to the presence of shunts at the atrial level. Patients with this cardiac malformation need early surgical treatment, otherwise they are prone to recurrent heart failure, pneumonia, and in severe cases, even irreversible pulmonary vasculopathy leading to death. 1, clinical manifestations Most children with secondary foramen ovale septal defect can be asymptomatic except for respiratory infections such as colds and flu, and their activities are not restricted, and they usually show shortness of breath, palpitations, and weakness only in their youth. after the age of 40, most patients’ symptoms worsen, and arrhythmias such as atrial fibrillation, atrial flutter, and congestive heart failure often appear, which is also an important cause of death. Unlike congenital heart disease ventricular septal defect, simple atrial septal defect does not cause life threatening and pulmonary hypertension at an early stage due to few early symptoms. Even if patients with this congenital heart disease fail to obtain timely diagnosis and treatment early on, this malformation can be treated surgically at any time during a person’s life when it is detected at any age, as long as there is still a relatively large amount of left-to-right shunt. In clinical work, we often encounter female patients who, during the course of pregnancy after marriage, have worsening symptoms or even cyanosis, which is very unfavorable for the development of the fetus and should be interrupted and receive surgical treatment to close the atrial septal defect before pregnancy. Another situation is that the patient gradually develops some non-specific symptoms such as weakness and shortness of breath around 40 to 50 years old, and this abnormal shunt of the heart is found after cardiac ultrasound examination, which can still be cured by receiving surgical treatment at this time. On the contrary, if the patient still fails to receive timely surgical treatment at this time, these symptoms will gradually worsen and may affect the life expectancy. 2.Examinations (1)Chest X-ray The main manifestations include congestion in the lung fields, mild to moderate enlargement of the heart shadow and protrusion of the pulmonary artery segment, and normal or slightly smaller than normal left ventricle and aorta. (2) Echocardiography and color Doppler can generally establish the diagnosis, which shows signs of right heart overload such as enlarged right atrium and right ventricle, co-mobility of the septum with the posterior wall of the left ventricle, interrupted continuity in the middle of the interventricular septum, and measurement of the size of the defect. Color Doppler can clarify the direction and velocity of the blood shunt and estimate the shunt volume. For venous sinus type defects ultrasound imaging may be difficult, hydrogen peroxide angiography helps to detect the shunt site, while transesophageal ultrasonography can obtain very clear images. (3) Other examinations ECG examination: It shows right deviation of the electrical axis, incomplete right bundle branch conduction block and right ventricular hypertrophy. Arrhythmias may be present in adult patients, with atrial fibrillation and atrial flutter being the most common. Right heart catheterization: The right atrial blood oxygen level exceeds the mean vena cava blood oxygen level by more than 1.9 solubilized percent, and the right heart catheter may also pass through the defect into the left atrium. The right heart catheterization can calculate the blood flow of pulmonary circulation and body circulation, determine the intracardiac shunt and measure the pulmonary artery pressure. 3. Indications and contraindications for surgery Children with a definite diagnosis of atrial septal defect should undergo surgical repair, especially if the defect is large. 1 to 5 years of age is the ideal age for surgical treatment. Surgery is contraindicated in children with severe pulmonary hypertension, clinically significant cyanosis, and cardiac insufficiency. The treatment of atrial septal defect currently includes two methods: ① surgical treatment: according to the surgical repair method can be divided into patch method and direct repair method, the patch can be polyester sheet or autologous pericardial sheet; ② interventional blocking treatment.