Introduction

Atrial septal defects (ASD) belong to a group of congenital heart anomalies that allow communication between the left and right sides of the heart and can present independently or concomitantly with other lesions. The communications are secondary to defects in atrial septal development. Secundum atrial septal and foramen ovale defects are often isolated while sinus venosus defects are associated with pulmonary vein abnormalities. Coronary sinus defects are associated with systemic vein abnormalities. This chapter will discuss the etiology and characteristics, diagnosis, treatment and outcomes of patients who present with these various forms of atrial septal defects, but discussion of primum atrial septal defects will be covered in the chapter on atrioventricular canal defects titled Atrioventricular Septal Defects (AVSD) (Atrioventricular Canal Defects) (Endocardial Cushion Defects).