Nowadays, there are many little babies who undergo heart ultrasound during physical examinations or for other conditions such as colds or pneumonia and find that the baby’s heart is basically normal, except for a small hole in the atrial septum, a condition medically known as foramen ovale unclosed. Is this a pre-existing heart condition? Does it require surgery? During the development of the embryo, the lunar fissure at the top of the septum ovale is not closed, which is called foramen ovale. This is a normal physiological phenomenon during infancy. The foramen ovale is a vital channel for the fetus to develop, and it is through this channel that blood from the mother’s umbilical vein enters the left side of the fetus’s heart and is then distributed throughout the body to provide the fetus with the oxygen and nutrients it needs to develop. At birth, with the first cry, the left atrium pressure rises and the foramen ovale should close functionally, while anatomical complete closure is usually not achieved until 5-7 months after birth. Therefore it is possible that the foramen ovale remains open up to one year of age, possibly with a small shunt, and even in 5% to 10% of individuals the foramen ovale remains open throughout life. The patent foramen ovale is mostly asymptomatic, difficult to hear murmurs, and the electrocardiogram and chest x-ray are normal. Therefore, it is not easily detected and is not taken seriously. The diagnosis of patent foramen ovale is mainly made by cardiac ultrasonography. The diameter of the foramen ovale is mostly below 5 mm has no effect on the hemodynamics of the heart. If the defect is larger, greater than 8-10 mm, with high fractional flow, it is called a central atrial septal defect and requires surgical repair. The timing of surgery should be aimed to be done when the child is 2-4 years old. It has long been thought that foramen ovale is not usually causing shunts between the two chambers and has no effect on the hemodynamics of the heart. In recent years, many studies have shown that there is a close association between foramen ovale and patients with unexplained stroke, decompression sickness, and migraine, so foramen ovale of 5 mm or less, closing it may also be beneficial for patients mentioned above. Previously, closure of patent foramen ovale relied on surgical procedures. In recent years, it has been rarely used. This technique is also safe, effective, and feasible for the permanent closure of open foramina. It is important to emphasize that although current studies suggest that management of patent foramen ovale is indicated in certain populations, the indications for surgery must be strictly limited, and generally no surgery is needed in children or, according to current studies, in adults who do not have these symptoms.