If the heart rate is listened to, a Doppler can be used and the sound can be heard. This sound is a simulated sound that can fully reflect the condition of the heart rate and is used more often when listening to the fetal heart, so it is relatively more common in obstetrics, while most of the general clinical departments do not have such instruments. Ultrasound, which can be simulated by instruments and equipment, can reflect the results of Doppler. Clinically, physicians use a stethoscope to perform measurements and listen to heart rate, and most will choose relatively clear areas, mostly the mitral valve auscultation area. However, some patients may have other auscultation areas that are relatively clear, depending on the actual situation. These auscultation areas, are optional. The stethoscope can hear abnormal heart sounds and murmurs, and the specific location of the lesion can be determined by combining the auscultation zones.