24-Hour Holter Monitor

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A Holter monitor is a small device that records your child’s heart rate and rhythm over a 24-hour period. It’s also used to detect any irregular heartbeats during the time it is worn.

How the Test Is Done

  • view of the chest showing where electrodes are locatedYour child’s Holter monitor will be put on at the hospital.
    • A technician will clean your child’s chest with an alcohol pad.
    • Small stickers called electrodes will be placed on the chest (Picture 1). Each electrode has a wire that attaches to the Holter monitor. The monitor is in a small carrying case that can be worn with a belt around the waist or over the shoulder with a strap.
  • A diary is used to record activities while the monitor is being worn.
  • Symptoms related to the heart or chest need to be written in the diary. Include the time of day, what your child was doing at the time, and what symptoms they had.
    • When a symptom occurs, pressing down on the square button on the outside of the monitor case to help track the symptoms written in the diary.
  • Other important things to track are: awake and asleep times, times of activity, quiet times, and when taking medicine(s).

During the Test

  • During the recording, the monitor will:
    • Beep for 1 minute to show it has started recording.
    • Slowly flash a green light during the 24-hour recording time.
    • Shut off on its own when the 24 hours is over.
  • Do not shower, take a bath, or swim with the monitor on. Your child can wash with a washcloth or towel while keeping the chest, stickers, and monitor dry.
  • Your child can do all of their normal activities during heart monitor recording unless your doctor or health care provider tells you otherwise.
  • Do not take the monitor off until the 24-hour recording period is done.

Risks and Possible Problems

Patients may have mild reactions to the electrodes, such as:

  • Skin irritation – Redness, itching, or a faint rash at the electrode site may appear. These will go away on their own.
  • An electrode comes loose – Replace it with a new (spare) electrode. You were given these when you got the monitor.
  • A wire comes off – Snap it back onto the electrode. You will be given a diagram to show the correct color and location of each wire.

After the Test

  • After the test, take the electrodes off the chest and throw them away.
  • Put the wires, Holter monitor, case, strap, and diary in the self-addressed, postage-paid envelope provided with the monitor right away.
  • Place the envelope in your mailbox for the US Postal Service to pick up, or in a public, blue USPS mailbox.
  • After the monitor is sent back, it takes about 10 days for the results to be ready. Your child’s doctor or health care provider will go over the results and any recommendations upon completion.


Holter Monitor (PDF)

HH-III-122 • ©2016, revised 2023 • Nationwide Children's Hospital