What you can expect

An electrocardiogram (ECG or EKG) may be performed at rest or during exercise. The process of an ECG involves the following:

Before the test, the patient will be asked to change into a hospital gown.
The patient will then be asked to lie down on a table. Electrodes—small, sticky patches—are then placed on different areas of the body.
Wires leading from these patches to a computer carry a signal that traces the patient's heart’s electrical activity on paper or on a computer, which the doctor will analyze. The electrical activity image looks like a line graph with peaks and valleys.
Once the test is complete, the patient will be able to resume normal activity.

Risks

Electrocardiograms don't pose any safety risks. Some skin irritation from the stickers on the electrodes may occur in some people, but this isn't a serious complication.