A Holter monitor is a type of ambulatory electrocardiogram (EKG or ECG). Ambulatory means that you are able to walk. This device can record the electrical activity of your heart while you move around to do your usual activities. You might wear it for 24 to 72 hours. The monitor is a lightweight, battery-operated tape recorder. You can wear it on a strap over your shoulder. Or you can wear it around your waist. The monitor is connected by wires to small pads or patches (electrodes) taped to your chest.

Holter monitoring is done to:

Look for and record irregular heartbeats that come and go or happen during certain activities.

Find out what is causing chest pain or pressure, dizziness, or fainting. These may be symptoms of heart problems.

Look for poor blood flow to your heart muscle. This is called ischemia.

Check to see if treatment for an irregular heartbeat is working.