A test that measures the natural electrical activity of the heart. It is used to diagnose and evaluate heart problems.

The electrical signals that regulate heartbeats start at the right atrium, one of the chambers located at the top of the heart, and travel to the bottom of the heart. As they travel through the heart, they signal the heart to contract in a synchronized fashion to pump blood throughout the blood vessels of the body. An electrocardiogram (also called an EKG or ECG) is used to determine how fast the heart is beating and whether the heart rhythm is steady or irregular. In so doing, it can uncover a number of potential heart problems, including a heart attack, lack of blood flow to the heart muscle, cardiac arrhythmias (irregular, fast, or slow heartbeats), and a heart that doesn’t pump blood forcefully enough to meet the body’s needs.


A commonly used type of electrocardiography, called a resting 12-lead EKG, is quick, simple, and painless. During this procedure, a technician attaches 12 electrodes to the skin on the chest, arms, and legs. Sometimes the technician shaves a person’s body hair where the electrodes will be attached so that they will better adhere to the skin. As the person lies still for a few minutes, the electrodes pick up electrical signals from the heart and relay them to a machine that records these signals, either on graph paper or on a screen. The entire test takes only about 10 minutes, after which the electrodes are removed.