Secundum atrial septal defect

Atrial septal defect (ASD) is a type of congenital heart disease, accounting for 30% of all congenital heart diseases. Secundum atrial septal defect is one type, accounting for approximately 80% of all ASDs. When the defect is located in the central part of the interatrial septum at the fossa ovalis, it is called a central type. In some patients, the defect is located lower, known as a low-lying defect. The progression of secundum atrial septal defect is relatively slow, with most patients developing symptoms in adulthood. Secundum atrial septal defect can occur independently or in conjunction with other intracardiac malformations, such as pulmonary valve stenosis, partial anomalous pulmonary venous drainage, and mitral stenosis.