1 an electrode placed on part of the body and connected to an electrocardiograph.
2 a record, made by the electrocardiograph, that varies with the site of the electrode. Electrocardiography is generally performed with the use of six limb leads and six leads placed on the precordium. The peripheral or extremity leads are designated I, II, III, AVR, AVL, and AVF. The chest leads are designated V1, V2, V3, V4, V5, and V6 to indicate the points on the precordium on which the electrodes are placed.