Ejection sounds can be heard in the pulmonary valve area as a manifestation of pulmonary stenosis, which is a common type of congenital heart disease due to abnormal embryonic development, but there may also be secondary pulmonary orifice stenosis, which is caused by other diseases, such as intrauterine fetal infections that can also cause the disease. The causes of embryonic developmental disorders vary among the various types of pulmonary artery stenosis. Let’s look at the specific causes below. What are the causes of ejection sounds that can be heard in the pulmonary valve area? Pediatric simple pulmonary stenosis: Simple pulmonary stenosis is a congenital malformation in which the pulmonary valve or funnel is narrowed while the ventricular septum is intact. Pulmonary stenosis is the main lesion of right ventricular outflow tract obstruction. The stenosis can be in different parts of the subpulmonary valve, valve, common pulmonary artery trunk and branches, among which simple pulmonary stenosis is the most common, accounting for 80% to 90%. Atrial septal defect: It is a common clinical congenital heart malformation, which is an abnormality of the original atrial septum during embryonic development, leaving a hole between the left and right atria. The atrial septal defect can occur alone or in conjunction with other types of cardiovascular malformations, and is more common in females, with a male to female ratio of approximately 1:3. The presence of a shunt at the atrial level can cause corresponding hemodynamic abnormalities. The atrial septal defects can be divided into two main categories: primary and secondary septal defects. As primary foramen ovale septal defects are often associated with mitral and tricuspid valve malformations. Secondary foramen ovale septal defect is divided into four types, including central defect (oval fossa defect), superior cavity defect (venous sinus defect), inferior cavity defect, and mixed defect, depending on the location of the defect. In the 6th week of embryonic development, the arterial trunk begins to separate into the aorta and the pulmonary artery, and three primitive nodules of valves begin to form in the intima of the pulmonary artery cavity and grow into the cavity, followed by absorption and thinning to form three pulmonary valves, and if the valves become impaired during growth, the junction of the three valve leaflets fuses into a dome-like protrusion of the mouth-like opening, which forms Pulmonary valve stenosis. The conical part of the cardiac bulb is absorbed into the right ventricular outflow tract (i.e., the funnel part) while the pulmonary valve is developing, and if the developmental disorder forms a hypertrophy of the outflow tract annulus muscle or a hypertrophic muscle bundle across the interventricular wall and septum, a funnel-shaped stenosis of the right ventricular outflow tract is formed. In addition, during embryonic development, the sixth pair of arterial arches develops into the left and right pulmonary arteries, which are connected to the small pulmonary arteries distally and to the pulmonary artery trunk proximally, and if development is impaired, they form branches of the pulsatile arteries or pulmonary artery trunk stenosis.