Tetralogy of Fallot, also known as Tetralogy of Fallot, is a common congenital heart condition. There are four problems in Tetralogy of Fallot, which include ventricular septal defect, stenosis of the pulmonary arteries, aortic riding and hypertrophy of the right ventricle. The most prominent symptom of this disease is cyanosis. A characteristic feature of the child is that the lips are cyanotic with pestle-like fingers. The end of the pestle finger is thick and greenish. Shortness of breath and paroxysmal dyspnea are also among the common symptoms, which appear after many kinds of crying or exertion and are more common in infants and children between two months and two years of age. Squatting in children: Children often walk a certain distance and then squat, with both lower limbs flexed and both knees against the chest. This is due to the fact that squatting leads to increased blood flow to the upper trunk, which improves central nervous system hypoxia and makes the child feel more comfortable. Hypoxic attacks: Severely ill patients can have hypoxic attacks, which manifest as pallor, limb weakness, paroxysmal syncope, and convulsions. Tetralogy of Fallot is a relatively common form of cyanotic congenital heart disease after arteriovenous ductus arteriosus, atrial septal defect, and ventricular septal defect. Ventricular septal defect and pulmonary artery stenosis are the basis for the pathophysiological changes that cause tetralogy of Fallot. The main issue affecting the child’s prognosis is the degree of pulmonary stenosis. Children with mild degrees of right and left pulmonary artery stenosis have less severe cyanosis and a better prognosis. The only effective treatment for tetralogy of Fallot is surgery. If a child does not have surgery, he or she will become increasingly purple and less active, and eventually the child will die prematurely, so it is important to come to the clinic early once cyanosis is detected.