The fast heartbeat of a child can be caused by both physiological and disease factors, physiological factors do not need to worry too much about the situation, while pathological factors such as hyperthyroidism, anemia, congenital heart disease and other diseases, you need to carry out targeted treatment. 1. Physiological factors: Generally, the heart rate of a newborn child can reach 120~140 beats per minute, while the heart rate of a premature child can reach 140~160 beats per minute. As the child’s age increases, the heart rate will gradually slow down, generally in the child close to the adult when the heart rate gradually decline to the adult range. In addition, physiological activities such as strenuous exercise, high mental stress, or drinking beverages containing caffeine or theophylline may also lead to a transient increase in heart rate. 2. Pathologic factors: (1) Congenital heart disease: such as ventricular septal defect, arterial conduit failure, atrial septal defect, tetralogy of Fallot, etc., due to the increased burden on the heart, it can be compensated to cause a faster heart rate; (2) Endocrine system diseases: for example, hyperthyroidism, due to the increase in basal metabolism and sympathetic excitability, which causes a faster heart rate; (3) Anemia: due to the body’s compensatory increase in oxygen consumption, it will also compensate by increasing the heart rate. If the child’s heart rate is fast, if you exclude the physiological factors, and the heart rate is fast, it is recommended to consult a doctor in a timely manner, under the guidance of the doctor, to improve the relevant examination, to clarify the cause of the disease, so as to target the treatment.