Patent foramen ovale. Persistent foramen ovale.Q21.12 Patent foramen ovale - ICD-10-CM Diagnosis Codes. Explore essential ICD-10 codes for Patent Foramen Ovale (PFO) diagnosis—accurate coding for PFO-related conditions in healthcare documentation and billing. The foramen ovale is a hole in the wall between the left and right atria of every human fetus. This hole allows blood to bypass the fetal lungs. A condition in which the foramen ovale in the atrial septum fails to close shortly after birth. Brain MRI was performed at 1year followup in 54 patients. 1. What is cardiomyopathy? Cardiomyopathy is a disease of heart muscle that is associated with cardiac dysfunction.