Children with bad heart can show symptoms of weakness, growth retardation and low immunity in the early stage. 1. Weakness: In newborns and infants, it is hard to eat milk, showing weakness, gasping due to shortness of breath, stopping to rest after sucking a few mouthfuls, feeling tired and sweating. 2. Growth retardation: compared with other normal children, slightly thin, activity tolerance is low, if the activity is too much, the heart can not afford, showing chest tightness, shortness of breath. 3. Low immunity: it is easy to catch colds or pneumonia. Other children may not catch colds very often, but children with bad hearts have frequent fever, runny nose, cough, and even pneumonia due to the decline in their physical condition, which is mainly related to low resistance. If you notice any of the above symptoms, you should go to the hospital for timely diagnosis and treatment.