The clinical manifestations of Tetralogy of Fallot include, firstly, cyanosis as the primary clinical symptom. The degree and onset of cyanosis are related to the severity of pulmonary stenosis, and it often appears in areas with abundant capillaries such as lips, fingers, toes, nail beds, and bulbar conjunctiva. Secondly, squatting symptoms are common among children; they often spontaneously squat for a while during walking or playing. Squatting, with the legs bent, reduces the venous return and thus decreases the load on the heart, temporarily relieving symptoms of hypoxia by reducing the right-to-left shunt. Thirdly, clubbing occurs due to long-term hypoxic conditions, which can cause capillary dilation and proliferation in the fingers and toes, and the local soft tissues and bones also grow and enlarge; fourthly, paroxysmal hypoxic attacks, which are most common in infants, can be triggered by breastfeeding, crying, emotional excitement, or anemia. These attacks suddenly occur and can lead to severe symptoms including difficulty breathing, fainting, convulsions, and even death.