Q21.10, Atrial septal defect, unspecified. Q21.11, Secundum atrial septal defect.Patent foramen ovale. Persistent foramen ovale. Q21.12 Patent foramen ovale - ICD-10-CM Diagnosis Codes. An atrial septal defect repair or closure device or a patent foramen ovale repair or closure device is present. CPT is a trademark of the AMA. Come and learn more about our work. An Ostium secundum atrial septal defect is a type of congenital heart defect called an atrial septal defect (ASD).