Congenital heart disease (atrial septal defect) Atrial septal defect (ASD) is a common clinical congenital heart malformation, which is an abnormality of the original atrial septum during embryonic development, leaving a gap between the left and right atria. Atrial septal defects can occur alone or in conjunction with other types of cardiovascular malformations, and are more common in females, with a male to female ratio of approximately 1:3. Due to the attention paid to the disease in recent years, the majority are detected in the pediatric period and treated accordingly. In clinical practice, it has been found that atrial septal defect is present in a minority of adult men and women. Therefore, it is recommended that adults who have never had a cardiac ultrasound have one done as soon as possible to rule out the disease. Clinical manifestations Most children with atrial septal defect are asymptomatic except for respiratory infections such as colds and flu, and their activities are not restricted until young adulthood when they show shortness of breath, palpitations, and weakness. Physical examination reveals that most children are thin and often show a slight bulge in the left anterior chest wall, an increased heart beat, and a palpable sense of right ventricular elevation. The typical presentation is a grade II-III systolic murmur between the 2nd and 3rd ribs at the left border of the sternum, accompanied by a hyperactive second heart sound and a fixed split, with the systolic murmur being caused by an increase in pulmonary valve flow velocity, and in a few patients, systolic tremor can be detected. The systolic murmur is due to an increase in pulmonary valve flow velocity, and in a few patients, systolic tremor can be detected. The diagnosis is usually established by cardiac ultrasound, which reveals signs of right heart overload such as enlarged right atrium and right ventricle, septal and posterior left ventricular wall motion in the same direction, interrupted continuity in the middle of the septum, and measurement of defect size. 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. Treatment Secondary foramen ovale septal defects over 1 year of age rarely close spontaneously. In asymptomatic children, the defect can be observed if it is less than 5 mm, and surgical repair before school age is generally recommended if there is right atrial and right ventricular enlargement. About 5% of infants have congestive heart failure within 1 year after birth. Surgery may also be performed in cases where medical treatment is ineffective. Adults with defects less than 5 mm and without right atrial enlargement can be observed clinically without surgery. Adults with right atrioventricular enlargement can be treated surgically, and those with combined atrial fibrillation can also undergo surgery at the same time, but surgery is contraindicated in those with pulmonary vascular resistance greater than 12 units, right-to-left shunt and cyanosis. Minimally invasive transcatheter catheter intervention is feasible for a subset of secondary foramen ovale defects if the location is appropriate. A nickel-titanium alloy blocker is inserted through the femoral vein and clamped to the atrial septal defect to close the defect for therapeutic purposes. No open-heart surgery is required. Prognosis The natural course of patients with unoperated atrial septal defects depends on the type of defect, the size of the fractional flow and the presence of other types of combined cardiac malformations; most can grow into adulthood, but life expectancy is shortened and patients die of congestive heart failure. The operative mortality rate for atrial septal defects secondary to foramen ovale alone is less than 1%. After surgery, due to hemodynamic improvement, the patient’s symptoms are significantly reduced or disappear, and their long-term survival rate is not significantly different compared to normal subjects. In adult patients, especially those with combined cardiac insufficiency, arrhythmias, or pulmonary hypertension, the operative mortality rate is relatively high. Sometimes, despite successful surgical repair, existing pulmonary hypertension and right ventricular hypertrophy persist, but the patient’s cardiac function can be improved, and his long-term survival rate is significantly higher than that of non-operated patients.