It refers to stenosis at the outlet of the pulmonary artery, resulting in obstruction of right ventricular blood drainage, including pulmonary valve stenosis, right ventricular funnel stenosis and stenosis of the suprapulmonary valve, main pulmonary artery and branches, which is more common in precordial disease and has a similar incidence in males and females. In severe stenosis, the development is poor. There is an elevated precordial area with a markedly enlarged turbinate and a grade 4-5 rough systolic murmur between the second ribs at the left sternal border. Conduction is toward the left axilla, subclavian and left dorsal shoulder. The murmur is loudest in funnel stenosis, with a low site and murmur loudness related to the degree of stenosis, accompanied by fine systolic tremor. The second sound of the pulmonary valve is diminished or absent. In mild to moderate stenosis, systolic jet sounds can be heard in the pulmonary valve region. The causes of the jet sounds that can be heard in the pulmonary valve region: 1, valvular pulmonary orifice stenosis Most common, three valve leaflets fuse into a garden cone shape, leaving a small 2-4 mm diameter hole in the center, and in some cases only two leaflets, with post-stenotic expansion of the pulmonary artery trunk. 2, right ventricular funicular stenosis The whole funicular muscle thickens, forming a long and narrow channel, or it can be a muscle septum type with annular stenosis, resulting in a third ventricle, if there is also a valve type stenosis called mixed stenosis. Pulmonary stenosis can involve part or all of the common pulmonary artery trunk, and can also extend to the left and right branches, often with anterior and posterior expansion of the stenotic segment. The stenosis of the pulmonary artery outlet causes obstruction of the right ventricular blood drainage, increases the systolic load of the right ventricle, increases the right ventricular pressure, while the pulmonary artery pressure is normal or decreases.