The first septum is the primary septum or the first septum, and the second septum is the secondary septum or the second septum. The primary septum grows in a semilunar shape from the dorsal wall of the midline of the atrium and grows toward the atrioventricular canal to fuse with the endocardial cushion, leaving a small hole at the caudal end of the atrioventricular septum, which is called the primary foramen. Before the primary foramen is closed, a hole is formed in the proximal cephalic portion of the primary septum, called the secondary foramen, which is the normal channel for blood during fetal life. At the same time, a sickle-shaped septum grows on the right side of the first septum from the atrial wall, called the secondary septum or the second septum, which does not continue to grow to separate the atria and stop midway, and the sickle-shaped depression is ovoid, called the oval fossa, where the primary septum and secondary septum fail to adhere and fuse leaving a small gap called the oval foramen, which is a vital channel necessary for the development of the fetus, and it is through this channel that the umbilical vein blood from the mother enters The blood from the mother’s umbilical vein enters the left side of the fetal heart and is then distributed throughout the body to provide the oxygen and nutrients needed for fetal development. Why does the foramen ovale not necessarily exist? At birth, with the first cry, the pressure in the left atrium rises, causing a functional closure of the left-sided primary septum partially against the right-sided secondary septum, which reaches anatomic closure within 1 year. If the foramen ovale remains unclosed in children >3 years of age it is called foramen ovale nonocclusion, which can also be interpreted as a small atrial septal defect. Foramen ovale is by far the most common congenital cardiac anomaly in adults, with 20% to 25% of adults having incomplete closure of the foramen ovale, which means that about 1 in 4 people in the normal population can be detected with this condition. For a long time, it was thought that incomplete closure of the foramen ovale generally did not cause shunting between the two chambers and had no effect on the hemodynamics of the heart, so it was considered “irrelevant”. So does it need to be treated or not? In some countries, the treatment of patent foramen ovale may not be positive, but in my country, due to the economic level and the pressure of life, the treatment attitude is not active. Generally, when the patients are small, they do not affect the body deficiency much and are not treated, but when they grow up, they are prone to brain embolism and other problems. Many studies in recent years have shown a close association between unclosed foramen ovale and patients with unexplained stroke. This is because through the unclosed foramen ovale, the following emboli can enter the left cardiac system causing the corresponding clinical symptoms: ① thrombus in the deep veins of the lower extremities or pelvic veins; ② air emboli due to diving disease or decompression sickness; ③ fat emboli formed after surgery or trauma. Moreover, the risk of recurrence remains high in patients with unclosed foramen ovale who have had thrombotic events. Therefore, treatment for the etiology and closure of the open foramen ovale in high-risk groups is expected to reduce the incidence of patients. In addition, it has also been found that patent foramen ovale is associated with the development of decompression sickness and migraine, so closing the foramen ovale may be beneficial for patients mentioned above. Therefore, it should be treated aggressively when economic conditions allow.