What is a Holter monitor?

A Holter monitor is a small device that records the electrical activity of your heart for 24 hours to a week at a time. The monitor is about the size of a deck of cards, and you wear it during your normal daily activities, including sleeping.

When is it used?

A Holter monitor is used to record your heartbeat all the time while you are wearing it. Symptoms that may be caused by a problem with your heart may not happen while you are in your healthcare provider’s office. Holter monitors are a safe and useful way to find heart rhythm problems that otherwise might not be found. Your provider may recommend this test if you have symptoms that come and go, such as:

• Feeling that your heart is beating harder, faster, or slower than usual or that it is skipping beats
• Shortness of breath
• Dizziness or fainting spells
• Chest pain

If you are being treated for a heart problem, a Holter monitor can also be used to see how well the treatment is working. You may need to wear a Holter monitor more than once, such as when you start a new medicine.

What happens during the test?

Wear loose-fitting clothes when you are wearing the monitor. Do not shower with it.

When you get a Holter monitor, small, sticky patches will be put on your chest. Men who have a lot of hair on their chest may have small areas shaved so that the patches will stick to their skin. Small wires are attached to the patches and connected to a small recorder. You can carry the recorder on a belt or shoulder strap.

You will be given a diary to record your activities and symptoms while you are wearing the monitor. Your provider will ask you to write down the date and time and:

• List your activities, such as walking, resting, and eating.
• List any symptoms you have, what you were doing when you had the symptoms.
• Write down when you take your medicine.

It is very important that you write down what you were doing when you had symptoms. Your provider needs to know what brings on your symptoms. Call 911 for emergency help right away if you have symptoms of a heart attack. The most common symptoms include:

• Chest pain or pressure, squeezing, or fullness in the center of your chest that lasts more than a few minutes, or goes away and comes back (may feel like indigestion or heartburn)
• Pain or discomfort in one or both arms or shoulders, or in your back, neck, jaw, or stomach
• Trouble breathing
• Breaking out in a cold sweat for no known reason
• If your provider has prescribed nitroglycerin for angina, pain that does not go away after taking your nitroglycerin as directed

Along with these symptoms, you may also feel very tired, faint, or be sick to your stomach.

What happens after the test?

When you return to the office or clinic, your healthcare provider will remove the patches and wires and review your diary and the information recorded by the monitor. Some monitors can send information to your healthcare provider’s office automatically, using technology similar to a cell phone. Your provider will discuss the results with you at your next visit, or sooner if needed.

What are the risks of this test?

Your skin might be irritated by the adhesive on the patches. Skin irritation will quickly go away after the patches are removed.