There are transthoracic echocardiograms and transesophageal echocardiograms. Transthoracic echocardiography should fully expose the chest because the heart is located on the left side of the chest cavity, and the patient’s left lateral position with the back to the physician can keep the heart close to the chest wall, which can reduce some interference of exhaust gas. If the patient has mobility problems, the probe can be applied with coupling agent in the horizontal position and placed on the left edge of the patient’s sternum, the apical and subxiphoid areas to perform a multi-sectional sweep of the heart and obtain relevant data of 2D, M-type color Doppler and spectral Doppler of the heart to evaluate the structure, function and blood flow of the heart. The patient should fast for 8 hours before the transesophageal ultrasound examination, and the patient should be given oral anesthetics before the examination. During the examination, the patient is placed in the left lateral position, the esophageal probe is fed into the patient’s mouth, the patient is made to make a swallowing motion, the probe is slowly fed in, and the probe is allowed to be inserted from the esophagus to the left atrium near the posterior aspect of the heart to observe the internal structures of the heart from the posterior aspect of the heart. Transesophageal ultrasound has a clearer image because it excludes the effect of exhaust gas on the heart.