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Holter Monitoring: About This Test

What is it?

A Holter monitor is a small machine that records the electrical activity of your heart. You wear it for at least 24 to 48 hours while you do all your normal activities.

The monitor has wires that attach to small electrode pads. These pads are taped to your chest.

This kind of machine has many different names. It is sometimes called an ambulatory monitor, an ambulatory electrocardiogram, or an ambulatory ECG. It can also be called a 24-hour ECG or a cardiac event monitor.

Why is this test done?

You may have this test to find out if you have a problem with your heart. Many heart problems can only be noticed when you are doing something. They may happen when you exercise, eat, have sex, or sleep. Or they may happen when you have a bowel movement or you feel stressed. Your Holter monitor will record the way your heart beats during all of these activities.

Holter monitoring also will:

  • Look for what may cause chest pain, dizziness, or fainting.
  • Check to see if treatment for an irregular heartbeat is working.

How can you prepare for the test?

  • Before the test, talk to your doctor about all your health problems. Tell him or her about all the medicines and vitamins you take.
  • Take a shower or bath before the pads are put onto your chest. You must not get the pads wet during the test.
  • Wear a loose blouse or shirt.

What happens before the test?

  • Areas of your chest may be shaved and cleaned.
  • The electrode pads are attached to your chest with a paste or gel.
  • Your doctor will show you how to wear or carry the monitor. For example, you might wear the monitor on a strap over your shoulder, hooked on a belt, or placed in a pocket. It does not weigh much.
  • Your doctor may give you extra instructions on how to use the monitor at home.

What happens during the test?

  • You need to record your activities and symptoms. Your monitor might have a button that you can push when you feel symptoms.
  • You will also keep a diary. You will write down the time your symptoms started. And you will write down what type of activity you were doing.
  • You can use the clock on the monitor to help you keep track of the time your symptoms started.

What else should you know about the test?

  • Your doctor will tell you if you need to stay away from strong electromagnetic fields while wearing a monitor. These may include items such as magnets, microwave ovens, and electric blankets.
  • The pads may make your skin itch a little. And your skin may look or feel irritated after the pads are removed.

How long does the test take?

You usually wear the monitor for 24 to 48 hours. Some people wear it longer than 48 hours.

What happens after the test?

  • Your doctor will give you extra instructions on what to do when the test is done.
  • You may return to the doctor's office or hospital to have the pads removed. Or you may be able to take them off yourself by following the instructions.
  • Your doctor will tell you how to return the monitor.
  • You can go back to your usual activities right away.

Where can you learn more?

Go to https://www.healthwise.net/patientEd

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Care instructions adapted under license by your healthcare professional. If you have questions about a medical condition or this instruction, always ask your healthcare professional. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.