Adult patent foramen ovale does not usually get larger. Adult patent foramen ovale does not usually result in abnormal blood shunts and low shunt flow and is usually asymptomatic, but may show significant clinical symptoms if the right atrial pressure exceeds that of the left atrium. Ovular foramen insufficiency is a congenital structural heart abnormality related to abnormal development of heart structures during embryonic period. Ovular foramen is usually formed during the 6th-7th week of embryonic development and is a blood flow channel between the atria that provides oxygen and nutrients to the developing fetus. If a septum develops between the atria during development, the secondary septum appears to stop growing and the primary septum fails to adhere and fuse with each other, leaving a smaller cleft, called the foramen ovale. In most people, the foramen ovale closes around 2 months of age. In most patients with an unclosed foramen ovale, the shunting of blood in the heart is relatively small and there are usually no obvious symptoms, but if the pressure in the right atrium exceeds that in the left atrium, it can lead to abnormal shunting of blood flow in the heart, which can easily produce paradoxical embolism, resulting in more symptoms such as migraine, unexplained stroke and decompression sickness, which can also lead to dizziness, difficulty breathing and limb weakness, but not increasing size of the foramen ovale. If an adult with unclosed foramen ovale has unexplained stroke or symptoms of transient cerebral ischemia, treatment with anticoagulants is usually required, such as heparin, which can be used. However, if these conditions recur, surgical closure of the foramen ovale, such as interventional occlusion, is usually required.