Electrocardiogram (EKG) | American Heart Association

An electrocardiogram measures the electrical activity of the heartbeat. With each beat, an electrical wave travels through the heart. This wave causes the muscle to squeeze and pump blood from the heart. A normal heartbeat on an EKG will show the rate and rhythm of the contractions in the upper and lower chambers.

EKG strip showing a normal heartbeat

An EKG is used to help diagnose and monitor many heart conditions including:

An EKG can show:

There’s no pain or risk associated with having an EKG. The test requires small stickers to be placed on the chest. There may be some minor discomfort when the stickers are remo

No. The machine only records the electrical activity of the heart. It doesn’t send electricity into the body.

Last Reviewed: Feb 24, 2025