It is generally believed that the existing heart murmur should disappear after surgery. In fact, most heart murmurs disappear after surgery, but some children still have heart murmurs. In some cases, after corrective cardiac surgery, the repair of defective patches or intracardiac myocardial bundles or valvular tendon bundles may affect the blood flow, resulting in a mild vortex of blood flow and the formation of a heart murmur, which is a mild systolic murmur and is not detrimental to the health of the patient. Some children still have shunt or obstruction after corrective cardiac surgery, so there is still a heart murmur, for example, there is still a shunt after ligation of arterial ductus arteriosus, a shunt after repair of ventricular septal defect, and an obstruction of the right ventricular outflow tract after surgery for tetralogy of Fallot, etc., and the heart murmur is more obvious, and it may be lighter or almost the same as the original murmur. Valve stenosis after shaping, stenosis obstruction basically lifted, but valve thickening and other lesions can not be eliminated, there will still be a mild systolic murmur or diastolic murmur, common such as pulmonary stenosis surgery is often still a murmur, which has no effect on the function of the heart. Atrioventricular valvuloplasty also often has a different degree of murmur, after surgery with the heart contraction enhancement, ventricular pressure increases, the murmur will be louder. The heart murmur in the above cases can be confirmed by Doppler echocardiography. If there is no residual shunt or residual obstruction, then there is no need to worry about it; if there is residual shunt or residual obstruction, then it depends on its degree to decide the treatment method.