Mitral valve insufficiency is characterized by an enlarged heart, and a blowing murmur can be heard during mitral valve systole through auscultation. Therefore, in chest X-ray examinations, an enlargement of the left lower cardiac border can be observed. Some severe cases may exhibit pulmonary artery hypertension, indicated by a prominent pulmonary artery segment; additionally, patients with heart failure may show increased pulmonary blood flow, all of which aid in the diagnosis of mitral valve insufficiency. However, this is not the definitive diagnosis, which should be determined through echocardiography. Especially through Doppler imaging, the enlargement of heart structures, the mosaic blood flow caused by mitral valve insufficiency, and changes in blood flow speed and direction can be clearly diagnosed. Therefore, the primary diagnostic tool for mitral valve insufficiency is not the chest X-ray, which only shows indirect signs, but echocardiography.