communication. There are 5 types of anatomic defects known: • Secundum ASD (ASD II): 80% to even more than 90% of ASDs in the adult population; located in the fossa ovalis region and its surrounding tissue. Background information on atrial septal defect Atrial septal defect (ASD) is one of the most prevalent congenital heart defects and may frequently remain undiagnosed until adulthood. 1-4 It is a consequence of various embryological disorders that cause interatrial