The Electrocardiogram (EKG) is a graphic recording of the electrical potentials provided by cardiac tissue.  The EKG picks up the heart's tiny electrical current at the surface of the body.  For the routine electrocardiogram, 10 electrodes are attached, 4 to the limbs and 6 to the chest wall.  The electrode attached to the right leg serves as a "ground."  When positioned, the electrodes can obtain 12 different views of the heart from 12 angles.  The result is called a lead.  Each lead records a picture of the moving impulse from a different point. 

Standard 12-Lead Electrode Positions

EKGs Help Diagnose Cardiac Problems

Heart Illustrations

Heart Conditions in Adults

Heart Conditions in Children

Vascular Problems

Stroke

Heart Disease Prevention

Cardiac Rehabilitation