Atrial Septal Defects (ASD)

Key Points

1. Atrial septal defects arise from abnormal atrial septal development and include the following types of ASD:

• patent foramen ovale
• secundum atrial septal defect (most common),
• primum atrial septal defect (discussed in the chapter about Atrioventricular Septal Defects),
• sinus venosus interatrial communication,
• coronary sinus defect, and
• common atrium.

2. Most significant ASDs cause a left-to-right shunt leading to chronic right heart volume overload, pulmonary overcirculation, and atrial arrhythmias.

3. A left-to-right shunt ratio of >1.5:1 is generally considered an indication for closure.

4. Surgical and transcatheter closure of ASDs have been compared, and neither approach has been shown to be clearly superior in terms of cost efficacy and outcomes. The proper approach must be matched to the unique anatomy of the individual patient.