The heart is the power organ of human blood circulation, its function is to inject oxygenated arterial blood from the lungs into the organs of the whole body for oxygen supply, and then inject venous blood from the whole body into the lungs for gas exchange. Therefore, the heart structure is divided into two parts: the left heart is responsible for injecting arterial blood into the whole body, and the right heart is responsible for injecting venous blood into the lungs. Both the left heart and the right heart have atria and ventricles. The normal left and right hearts are not connected to each other and are separated by the interatrial and interventricular diaphragm. Second, foramen ovale is a congenital defect of the heart The foramen ovale is located in the atrial septum, which is formed during the embryonic period. Since there is no pulmonary circulation in the fetus, the foramen ovale is the conduit through which blood flows in the fetus. After birth, the pulmonary circulation forms and the foramen ovale gradually closes. If the foramen ovale does not close in children older than 3 years old, the foramen ovale is not closed, leaving a very small gap, called the foramen ovale is not closed. Because the foramen ovale is a channel between the right and left heart, it may cause blood to shunt between the left and right heart. Usually, the pressure in the left atrium is higher than that in the right atrium, and a small amount of arterial blood from the left atrium flows into the right atrium, which produces a left-to-right shunt that usually does not cause symptoms. During increased pressure in the right heart (e.g., coughing, breath-holding, diving), venous blood from the right atrium flows into the left atrium, producing a right-to-left shunt. The right-to-left shunt is also usually asymptomatic, but if some material from the right heart system (venous system) enters the left heart with the blood flow it can produce symptoms called reverse blood flow or paradoxical embolism. Fourth, paradoxical or paradoxical embolism of the brain with unclosed foramen ovale can be seen in the following cases 1, thromboembolism: some unexplained cerebral embolism can be caused by unclosed foramen ovale, because the blood flow in the venous system is slower than that in the artery, which can easily form thrombus, such as microemboli in the venous blood of the lower limbs can cause paradoxical embolism of the brain through the foramen ovale. In addition, domestic and foreign reports of atrial septal tumor combined with unclosed foramen ovale, the nearby blood flow is irregular, local thrombus can be formed, and the embolus can also cause cerebral embolism after dislodging into the left heart. 2, air: decompression sickness of divers is caused by air embolus entering the arterial system through the foramen ovale. 3, fat: fat embolus after surgery and fracture enters the arterial system through the foramen ovale, and fat embolus entering the brain can cause neurological dysfunction. 4, hypoxemia. 4. Hypoxemia: When there is right heart infarction, pericardial effusion and severe tricuspid regurgitation, etc., the increased pressure in the right heart produces more right-to-left shunt, and as the blood flow with low oxygen content enters the arterial system through the unclosed foramen ovale, it can cause the patient to have arterial hypoxia symptoms of dyspnea and dizziness. v. What is the relationship between migraine and unclosed foramen ovale Characteristics of typical migraine: one side of the head The typical migraine is characterized by throbbing pain on one side of the head, accompanied by photophobia, vomiting and nausea, often unable to work and study normally for one day or longer. A few migraine patients have aura (sensory signals before each attack): flash hallucinations and other visual deficits are common. Foreign authors and our clinical trials have shown that interventional occlusion of the foramen ovale in migraine patients combined with migraine can make the migraine disappear. Interventional occlusion of patent foramen ovale offers a new possibility for the treatment of migraine patients, so that migraine may not be a lifelong disease.