A heart murmur is a noise produced between each heartbeat, an unusual sound produced by the flow of blood through the heart. Each contraction and diastole of the heart is a heartbeat. When a doctor listens to a child’s heartbeat, the heartbeat is a “thump”, usually between “thump” and “thump” and between “thump” and “thump” and the next “thump”. There should be no sound between “dong” and “da” and between “da” and the next “dong”, but if there is an extra sound, it is called a heart murmur. The vast majority of heart murmurs are not serious problems. There are three types of heart murmurs: physiologic murmurs, functional murmurs, and pathologic murmurs. Physiological murmurs are limited in location, are systolic murmurs, short in duration, low in pitch, and change with body position, breathing, and movement. The new functional murmur is caused by a few diseases, such as anemia, hyperthyroidism, etc. The murmur disappears as the disease is cured. Pathological murmurs are caused by abnormal turbulent vortex in the flow of blood due to cardiac lesions and abnormal valve opening and closing, with long duration and loud and rough tone. Physiologic murmurs are sounds made by the normal heart and are more common in early childhood, but by adolescence, simple murmurs usually subside. Murmurs in congenital heart disease can usually be detected at birth or a few months after birth, and occasionally a few months later, as a result of abnormal blood flow due to structural abnormalities in the heart. Acquired murmurs in childhood may be caused by rheumatic fever, rheumatic heart disease, myocarditis, cardiomyopathy, etc. Most physiological murmurs (benign murmurs) do not require treatment and regular follow-up is sufficient; pathological murmurs with structural abnormalities of the heart, such as atrial septal defect, ventricular septal defect, patent ductus arteriosus or some complex malformations, etc., depending on the size of the defect, determine the treatment plan and let the doctor decide whether to review it regularly or operate early. In the case of pathological murmurs due to acquired heart disease such as rheumatic heart disease, myocarditis, etc., the primary cause is treated with medication.