Tetralogy of Fallot is the most common form of cyanotic preconditioning in clinical practice, accounting for approximately 10% of congenital heart disease and 50% of cyanotic heart disease. The chance of having a child with one parent with tetralogy of Fallot is 1.5%. Patients with tetralogy of Fallot have the following malformations, including ventricular septal defect, aortic span, pulmonary artery and/or pulmonary valve stenosis and right ventricular hypertrophy, and may also have other cardiac malformations such as atrial defect, right-sided heart, bilateral superior vena cava, patent ductus arteriosus, partial pulmonary venous malformation drainage, atrioventricular coaptation perpetuation, and tricuspid valve insufficiency. Question 1: What is the presentation of the child? After birth, children with tetralogy of Fallot have varying degrees of cyanosis of the face, lips, and nail bed, growth retardation, fatigue, and increased cyanosis after exertion. Respiratory distress and weakness often force the child to rest in a squatting position, and some children may have fainting spells or even epileptic convulsions due to severe hypoxia. The mortality rate can be up to 25% if the child is not operated within 1 year of age. In severe pulmonary artery stenosis, the mortality rate is 40% within 3 years of age, 75% within 10 years of age, and 95% within 40 years of age. patients over 40 years of age tend to die from chronic heart failure and hypoxia. In case of combined pulmonary atresia, the child dies within 1 month after birth due to the closure of the arterial duct, and the mortality rate is 75% within 3 years of age and 92% within 10 years of age. Question 2: What is the treatment? The diagnosis of tetralogy of Fallot is not difficult, as the child has typical symptoms and signs, and the diagnosis can usually be made after a cardiac ultrasound. Once the diagnosis is confirmed, surgery should be performed as soon as possible. With the improvement of cardiac surgery technology, the age of patients with tetralogy of Fallot is getting younger and younger, and the surgery is usually done before the age of 2 years. Radical surgery is feasible in the majority of children, and palliative (body-lung bypass) surgery is considered only when radical surgery is not indicated, followed by radical surgery at a later stage. Radical surgery is effective, and most children can return to normal life. Question 3: Can adults still undergo surgery? With the improvement of medical treatment, patients with tetralogy of Fallot in older children and adults have become rare in recent years, but they still exist. Older patients tend to have secondary cardiac pathologies, such as cardiac hypertrophy and myocardial fibrosis, but these patients often have better results with surgery because the pulmonary artery and left ventricle are better developed. Even at the age of 40, radical surgery is feasible for adult patients as long as they have not experienced heart failure. Question 4: What are the results of surgery? In recent years, the mortality rate of radical surgery for tetralogy of Fallot has decreased significantly, with a mortality rate of only 3-5% in infants and children and 1.3-14% in adults. Of course, this is closely related to the experience of the operator. In general, the causes of early postoperative death in patients are mostly low cardiac output syndrome, perfused lung or pulmonary edema, renal failure, pericardial tamponade, arrhythmias and infection. The vast majority of patients recover well after surgery, cyanosis and hypoxemia can disappear immediately, and pestle fingers (toes) gradually return to normal, but most patients can still hear varying degrees of heart murmurs. Patients can work and study normally, get married and have children, and do not need long-term medication.