How does it work?

The Holter monitor is a recording device. The monitor has a strap that you wear over your shoulder or around your waist. The Holter monitor is battery-powered and holds a regular-sized cassette tape, much like one you would use in an audio tape player. The monitor has 5 to 7 wires called leads. The leads attach to metal disks called electrodes, which you wear on your chest. These electrodes are very sensitive, and they can pick up the electrical impulses of the heart. The impulses are recorded by the Holter monitor and give your doctor a 24-hour record of your heart's electrical activity.

What should I expect?

Holter monitoring is a painless test. You will need to go into your doctor's office to be fitted for the monitor. It is a good idea to bathe before you go to the doctor's office, because once you are fitted with the Holter monitor, you cannot get it wet in the shower or bathtub.

A nurse will clean the areas with alcohol and then place the electrodes on your chest. For men, the nurse may have to shave some small areas of your chest. The electrodes stick to the skin with a gel. Sometimes, an electrode and lead wire will be taped to your chest to prevent them from moving around.

You will wear the Holter monitor for at least 12 to 24 hours. While you are wearing the monitor, you will be asked to keep a log of your daily activities: what you did and at what time. This will help the doctor figure out what you were doing during the times that there were abnormal readings. Otherwise, you can do your typical activities, except those that might get the Holter monitor wet.

After 24 hours (or more), you will go back to your doctor's office to have the electrodes removed. This may cause some discomfort, similar to having a bandage pulled off.