Many parents find a small hole in the atrial septum of their child’s heart, mostly under 5 mm in diameter, during a physical examination of their newborn baby and request surgery for their child. In fact, this condition is medically known as patent foramen ovale (PFO for short). The foramen ovale is a vital channel necessary for the development of the fetus, and it is through this channel that blood from the mother’s umbilical vein enters the left side of the fetus’ heart and is then distributed throughout the body to provide the oxygen and nutrients needed for fetal development. At birth, with the first cry, the pressure in the left atrium rises and the oval fossa valve is pressed against the edge of the oval fossa to form a functional closure, which is usually complete anatomically until 5-7 months after birth. Therefore, it is possible that the foramen ovale remains open up to one year of age and may have a small amount of shunting, and even in 5-10% of individuals the foramen ovale remains open and unclosed for life, but there is no effect on the hemodynamics of the heart. Therefore, a patent foramen ovale in infancy is a normal physiological phenomenon, not a precordial disease, and usually does not require surgery. However, if the defect in the central atrial septum is large, 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 young child is 2-4 years old. The foramen ovale, a channel between the left and right ventricles during fetal life, is where the umbilical vein blood from the mother enters the left side of the fetal heart cavity and is then distributed throughout the body to provide the oxygen and nutrients needed for fetal development. At birth, with the first cry, the pressure in the left atrium rises and the oval fossa valve is pressed against the edge of the oval fossa to form a functional closure, which is usually complete anatomically until 5-7 months after birth. It is possible for the foramen ovale of the baby’s heart to remain open up to one year of age, and there may be a small amount of shunting, and in even 5-10% of people the foramen ovale remains open and unclosed for life, but there is no effect on the hemodynamics of the heart. In some adults, who have frequent headaches for which no cause can be identified, a mild mixture of arterial and venous blood is found after measuring the oxygenation of the carotid blood, and a slight foramen ovale non-occlusion is one of the causes of this condition. The oval foramen ovale is a normal physiological phenomenon in infancy, not a preexisting heart disease, and usually does not require surgery. However, if the central atrial septal defect is large, greater than 8-10 mm, with high fractional flow, it is called a central atrial septal defect and requires surgical repair.