The five leads are located at five different locations in the chest, with the upper left position at the junction of the midclavicular line and the first intercostal space at the left edge of the sternum. The lower left position is at the junction between the midline of the left clavicle and the level of the glabella. The upper right position is at the junction of the midclavicular line of the right edge of the sternum and the first intercostal interval. The lower right position is at the junction of the midline of the right clavicle and the level of the fenestra, with the fourth intercostal interval at the left edge of the sternum in the middle. The ECG monitor is a more commonly used clinical monitoring tool that can simultaneously monitor the patient’s dynamic ECG as well as blood pressure, blood pressure saturation, respiration, pulse rate and other parameter changes, and also has a wealth of alarm upper and lower limit setting functions. Pay attention to the standardized operation, let the patient take a flat or semi-recumbent position, first connect the power supply, then turn on the main switch, position the patient’s chest to affix the electrode piece part, wipe the local skin with saline cotton ball, then affix the electrode piece and connect the ECG monitor lead.