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Holter Monitor

UPMC Content 2

A Holter monitor is a device that continuously records your heart’s rhythm during daily activities (usually for 24 hours). This is also called an ambulatory electrocardiogram. The monitor records your heart’s rhythm through electrodes that are placed on your chest. Electrodes are small adheive patches attached by wires to a monitor. This test helps show how your heart responds to normal activity or to certain medications.

Why is this test done?

There are many reasons your doctor may order this test:

  • To help detect irregular heart beats (cardiac arrhythmias, pronounced ay-RITH-me-uhs)
  • To help evaluate chest pain
  • To help check the heart’s activity after a heart attack
  • To help check the heart’s activity after a pacemaker has been inserted
  • To help check how certain medicines are working
  • To help discover the cause of certain symptoms such as difficulty breathing, dizziness, light-headedness, or fainting

How should I prepare for the test?

Wear loose-fitting clothing with a shirt or blouse that buttons down the front. This will help keep the electrodes from becoming loose. Other than that, there is no special preparation for this test. You may eat and drink before this test.

How is this test done?

You will be told where and when to have the Holter monitor put on and taken off. First, your chest will be cleansed. It may also be shaved. Having clean skin will help the electrodes stay on until the test is done. Electrodes will be stuck to your chest. This is painless. You will be told what to do if any of the electrodes loosen or fall off during the test.

The electrodes are attached with wires to a portable (battery operated) monitor. The monitor is worn in a pouch, which might be on a strap around your waist, shoulder, or neck.

While wearing the monitor, continue to go about your daily activities in your usual way. You will be asked to keep a diary of your activity, medicines, and symptoms while wearing the monitor.

It is important to keep the monitor dry.

  • Do not shower or take a bath until the monitor is removed.
  • It is OK to take a sponge bath, but be careful not to get the monitor wet.

Do not disconnect the lead wires or electrodes. This will interfere with the recording.

Keeping your diary

It is very important that you fill in the diary. Write down any activities that you do and the time you do them. Some examples of activity are:

  • Walking
  • Stair climbing
  • Exercise
  • Sexual activity

You also must include:

  • Eating and drinking
  • Medicines taken
  • Periods of stress

Write down any symptoms you have and what time you experienced them. The following symptoms are important to record:

  • Chest pain or discomfort
  • Any other pain
  • Shortness of breath
  • Dizziness or light-headedness
  • Fainting
  • Heart palpitations (racing or pounding heart beat)
  • Tiredness or fatigue
  • Nausea

Some Holter monitors have an “EVENT” button. Press this button when you experience any symptoms. When the EVENT button is pressed, it “marks” the recording. If your monitor has this button, you will be shown how to use it.

What to avoid

Certain things can interfere with your Holter monitor’s recording. While wearing the Holter monitor, avoid the following:

  • Magnets
  • Metal detectors
  • Electric blankets
  • High voltage areas

Time’s up!

Return to the place where you received your monitor, at the time you were told to. The electrodes and monitor will be removed.


A computer will analyze the recording and print out a report. Your doctor will analyze the report and your diary. He or she will talk with you about the results. Depending on the results of this test, additional tests or treatments may be ordered. Your doctor will discuss these with you.​