ICD 10 code for Patent foramen ovale. Get free rules, notes, crosswalks, synonyms, history for ICD-10 code Q21.12.Patent foramen ovale. Persistent foramen ovale. Atrial septal defect: Q21.1; Congenital malformation of cardiac chambers and connections, unspecified: Q20.9. ICD-11. Learn the 4 things you need to know to confidently rule out PFO. DISEASES inferred 14. Q21.12 Patent foramen ovale - ICD-10-CM Diagnosis Codes. Atrial septal defect (ASD) and patent foramen ovale (PFO) are both hole-in-heart conditions. The most common types of hole-in-heart problems are conditions like atrial septal defect (ASD) and patent foramen ovale (PFO).