If an infant has a heart murmur, there are the following clinical manifestations: first, a bruise on the lips and mouth. The cause of heart murmurs in infants is due to heart valve closure insufficiency, due to ventricular septal defects and atrial septal defects, etc., which can cause bruising of the lips and mouth after the child is deprived of oxygen. Secondly, it manifests as difficulty in feeding. Because the infant’s congenital heart disease will affect breastfeeding, the infant’s hypoxia symptoms will become more obvious after breastfeeding, causing the infant’s weight to be significantly lower. Finally, the infant will also have recurrent respiratory infections, and the respiratory infections are difficult to control due to the lack of oxygen caused by the heart disease, resulting in the lungs being susceptible to infection caused by the symptoms. Because of the lack of oxygen in the body after congenital heart disease, the resistance of the lungs will be reduced after the lack of oxygen.