The location of 24-hour ambulatory ECG leads is similar to that of the general ECG, especially the location of the anterior chest leads is the same as that of the general ECG leads. lead V1 is at the 4th intercostal space on the right edge of the sternum, lead V2 is at the 4th intercostal space on the left edge of the sternum, lead V4 is at the 5th intercostal space on the left midclavicular line, lead V3 is between leads V2 and V4, lead V5 is at the 5th intercostal space on the anterior axillary line, and lead V6 is at the 5th intercostal space on the midaxillary line. To avoid the influence of limb activity on the leads as well as the ECG signal, the limb leads are different from the normal ECG leads. 24-hour ambulatory ECG limb leads, located under the left and right clavicles, represent the left and right upper limbs, while the left and right abdomen represent the left and right lower limb leads.