Holter Monitor
  • What is a Holter Monitor?

    A holter monitor is a medical device that records the heart’s electrical activity. Doctors most often use these monitors to diagnose arrhythmias (ah-RITH-me-ahs).

    Arrhythmias are problems with the speed or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.

    A holter monitor is also used to detect silent myocardial ischemia (is-KE-me-ah). In this condition, not enough oxygen-rich blood reaches the heart muscle. “Silent” means that no symptoms occur.

    These monitors also can check whether treatments for arrhythmia and silent myocardial ischemia are working.

    This article focuses on using Holter to diagnose problems with the heart’s rate or rhythm.


    A holter monitor is similar to an EKG/ECG (electrocardiogram). An EKG/ECG is a simple test that detects and records the heart’s electrical activity. It’s the most common test for diagnosing a heart rhythm problem.

    However, a standard EKG/ECG only records the heartbeat for a few seconds. It won’t detect heart rhythm problems that don’t occur during the test.

    A holter monitor is small a portable device, which you can wear one while you do your normal daily activities. This allows the monitor to record your heart for a longer time than an EKG/ECG.

    Some people have heart rhythm problems that only occur during certain activities, such as sleep or physical exertion. Using a holter monitor or event monitor increases the chance of recording these problems. A holter monitor records your heart’s electrical activity the entire time you’re wearing it.

  • Types of Holter and Event Monitors

    Holter Monitors

    Holter monitors are sometimes called continuous EKG/ECGs (electrocardiograms). This is because holter monitors record your heart rhythm continuously for 24 to 48 hours.

    A holter monitor is about the size of a large deck of cards. You can clip it to a belt or carry it in a pocket. Wires connect the device to sensors (called electrodes) that are stuck to your chest using sticky patches. These sensors detect your heart’s electrical signals, and the monitor records your heart’s rhythm.

  • Who Requires a Holter Monitor?

    Your doctor may recommend a Holter monitor if he or she suspects you have an arrhythmia. An arrhythmia is a problem with the rate or rhythm of the heartbeat.

    Holter monitors are most often are used to detect arrhythmias in people who have:

    • Fainted or sometimes feel dizzy. A monitor may be used if causes other than a heart rhythm problem have been ruled out.
    • Reccuring palpitations (pal-pi-TA-shuns) that recur with no known cause. Palpitations are feelings that your heart is skipping a beat, fluttering, or beating too hard or fast. You may have these feelings in your chest, throat, or neck.

    People who are being treated for heart rhythm problems may also require a holter monitor. The monitors can show how treatments are working.

    Heart rhythm problems may only occur at certain times, such as during sleep or physical exertion. Holter monitors record your heart rhythm while you perform your normal daily routine. This allows your doctor to see how your heart responds to different daily activities, which can help diagnose the problem.

  • What To Expect Before Using a Holter Monitor

    Your doctor will do a physical exam before ordering a holter monitor.

    Holter monitors have electrodes, which are attached to the chest. It’s important that the electrodes have good contact with your skin. Poor skin contact may result in an inconclusive report.

    Oil, too much sweat, and hair can keep the electrodes from sticking to your skin. You may need to shave the area on your chest where your doctor will attach the patches. If replacement of the electrodes is required, you’ll need to clean the area with a special prep pad that the doctor will provide.

    You may need to use a small amount of special paste or gel to help the electrodes stick to your skin.

    Recording the Heart’s Electrical Activity

    All monitors record the heart’s electrical activity. So it’s important to maintain a clear signal between the sensors (electrodes) and the recording device.

    In most cases, the sensors are attached to your chest with sticky electrodes. Wires connect the sensors to the monitor. You usually can clip the monitor to your belt or carry it in your pocket. (Postevent and implantable loop recorders don’t have chest sensors.)

    Too much movement can pull the electrodes away from your skin or create “noise” on the EKG/ECG (electrocardiogram) strip. An EKG/ECG strip is a graph showing the pattern of the heartbeat. Noise looks like a lot of jagged lines; it makes it hard for your doctor to see the real rhythm of your heart.

    When you have a symptom, stop what you’re doing. This will ensure that the recording shows your heart’s activity rather than your movement.

    Your doctor will tell you whether you need to adjust your activity level during the testing period. If you exercise, choose a cool location to avoid sweating too much. This will help the electrodes stay sticky.

    Other everyday items can also disrupt the signal between the sensors and the monitor. These items include magnets, metal detectors, microwave ovens, and electric blankets, electric toothbrushes, and electric razors. Avoid using these items. Also avoid areas with high voltage.

    Cell phones and MP3 players (such as iPods) may interfere with the signal if they’re too close to the monitor. When using any electronic device, try to keep it at least 6 inches away from the monitor.

    Keeping a Diary

    When using a holter monitor, you need to keep a diary of your symptoms and activities. Write down when symptoms occur, what they are, and what you were doing at the time.

    The most common symptoms of heart rhythm problems include:

    • Fainting or feeling dizzy.
    • Palpitations. These are feelings that your heart is skipping a beat, fluttering, or beating too hard or fast. You may have these feelings in your chest, throat, or neck.

    It’s important to note the time that symptoms occur, because your doctor matches the data with the information in your diary. This allows your doctor to see whether certain activities trigger changes in your heart rate and rhythm.

    You also should include details in your diary about when you take any medicine or if you feel stress at certain times during the testing period.

    What To Expect With Specific Monitors.

    Holter Monitors

    Holter monitors are about the size of a large deck of cards. You’ll wear one for 24 to 48 hours. You can’t get your monitor wet, so you won’t be able to bathe or shower. You can take a sponge bath if needed.

    When the testing period is complete, you’ll return the device to your doctor’s office. The results will be stored on the device.

    The recording period for a standard holter monitor may be too short to capture a heart rhythm problem. If this is the case, your doctor may recommend a wireless holter monitor.