Patent foramen ovale. Q21.12 Patent foramen ovale - ICD-10-CM Diagnosis Codes.Atrial septal defect, unspecified. Q2111, Secundum atrial septal defect. Q2113, CC, 54 codes, Coronary sinus atrial septal defect. Explore essential ICD-10 codes for Patent Foramen Ovale (PFO) diagnosis—accurate coding for PFO-related conditions in healthcare documentation and billing. The staff collect diagnostic information on. He also has expertise in closing patent foramen ovale (PFO) and atrial septal defects (ASD). A previous fatal case described only autopsy findings including a patent foramen ovale and multiple diffuse air emboli. Toni: Honoraria; Modest; Sanofi-Aventis.