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Electrocardiogram (ECG or EKG) at Cadence Heart

Holter Monitoring

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What is Holter monitoring?

Holter monitoring is a type of ambulatory ECG test which involves the use of a small wearable device that continuously measures your heart’s electrical activity. It is a portable device that allows your doctor to monitor your heart’s activities for a period of 24 hours to 2 weeks. This is done to see how your heart beats while you go about your daily activities, and to discern whether certain actions or conditions trigger an abnormal heart rhythm.

What does a Holter monitor do?

Holter monitoring system tracking cardio problem failure sick irregular disorders transducer therapy cardioversion heartbeat non invasive diagnosis treat

The Holter monitor records the same information that an ECG machine does — your heart’s rate and rhythm. It is used to determine how your heart responds to normal activity. The two main differences are that the Holter monitor is a portable device and the test is carried out over a longer period as compared to the resting ECG test.

A Holter monitor helps continuously record the heart’s rhythm, helping detect irregularities in the heart rhythms (arrhythmias), which may not always show up during a resting ECG test. Episodes of arrhythmia occur sporadically and thus are hard to detect with a resting ECG which lasts only for a few minutes.

When is Holter monitoring done?

Holter monitoring is often carried out when:

  • Your ECG results do not show a clear cause for your symptoms.
  • Your doctor suspects that you have irregular heart rhythms (arrhythmias).
  • You have started a new course of medication.

This allows your cardiologist to:

  • Evaluate symptoms that can’t be reproduced during a resting ECG or stress test.
  • Find the cause of heart-related symptoms (chest pain, palpitations, dizziness, fainting, etc).
  • Assess the risk of cardiovascular conditions.
  • Evaluate the effectiveness of medications/treatments for a previous heart condition.

It may be used to diagnose:

  • Atrial fibrillation and flutter
  • To determine cause of heart palpitations
  • Paroxysmal supraventricular tachycardia
  • To rule out cardiac arrhythmia as cause of fainting spells
  • Bradycardia
  • Ventricular tachycardia
  • Multifocal atrial tachycardia

Who is Holter monitoring recommended for?

Holter monitoring is usually recommended if your ECG results are inconclusive. It is recommended to patients who experience symptoms such as:

  • Chest pains
  • Palpitations or fluttering
  • Tiredness or fatigue
  • Shortness of breath
  • Unexplained dizziness and fainting spells

While the ECG is a quick test done to assess the general condition of your heart at that current moment in time, Holter monitoring is done to get a more detailed picture of your heart’s rhythm.

Certain types of Holter monitors have an event recorder to note your symptoms, activities, stress level, food intake, etc. as you go about your day. Otherwise, your cardiologist may require you to take note of the events in your day to find if certain activities or conditions trigger an abnormal heart rhythm.

How to prepare for a Holter monitoring test

There is no special preparation needed for a Holter monitoring test. You can eat and drink as you usually would throughout the test. In fact, it would be beneficial for you to go about your daily activities as you normally would get the most accurate results.

However, as the Holter monitor cannot get wet, you may want to have a bath before your visit to the cardiologist. Additionally, to ensure that the electrodes attach to the skin securely, some parts of your chest area may be shaved.

After being fitted for the monitor, the technician will tell you how to wear the device and provide you with a list of things you can and cannot do. A general list can be found below.

What happens during Holter monitoring?

When you come to your appointment for Holter monitoring you can expect the following:

1. You will have to remove accessories around your chest to ensure that it does not interfere with the reading. You will then be asked to remove your upper clothing.

2. The technician/doctor will attach the electrodes around your chest and abdomen area. In some cases, patches of hair will have to be shaved to ensure that the electrodes can stick well. The Holter monitor will then be connected to the electrodes.

4. You will then be given a belt, pocket, or bag to hold the monitor. You will have to keep the monitor and electrodes on you at all times during the test period.

3. Newer Holter monitor devices come in the form of a single patch attached to the chest and do not need additional electrodes attached. This makes the testing period more convenient and comfortable.

5. Your technician will brief you on:

a. How to place and carry the monitor.

b. How to check and change batteries.

c. What you can and cannot do.

d. How to note events (symptoms & activities) as you go with your day.

6. Once everything is done, you can go back to normal activities.

After the test period, you will have to return to your doctor’s office to return the monitor and your event diary. If you experienced symptoms, do tell your doctor as it might require further testing or treatment. You will be asked to return to the clinic 7-14 days later to review your results.

What should I do/ not do while a Holter monitor is attached to me?

Things you should do during the Holter monitoring:

  • Keep electrical appliances (phones, laptops, etc.) at least 15cm away from the Holter monitor.
  • Take note of when your symptoms happen, what you are doing when the symptom occurs, your stress level, and what you have eaten recently.
  • Proceed with your daily activities as you normally would. Light exercises are fine but make sure that the electrodes and monitor are in place.
  • Limit alcohol and caffeine consumption.

Things you AVOID during the Holter monitoring:

  • Water (showering, swimming, water sports). Certain monitors are waterproof and you can shower while wearing them.
  • Vigorous exercise (excessive sweating may cause electrodes to loosen)
  • Smoking
  • Microwave
  • Using electric blankets, electric razors and electric toothbrushes
  • Getting an X-ray
  • Magnets
  • High-voltage areas
  • Metal detectors

Benefits vs. Risks of Holter monitoring

Image of a Cardea SOLO patch electrode Holter

As you will be wearing the ambulatory monitor for a prolonged period, you may experience some discomfort. Fortunately, there are advancements in technology that allow for a more comfortable experience, such as a patch electrode Holter, where only a piece of singular adhesive advice will need to be attached to the chest.

As long as instructions are followed closely, there are no risks involved with Holter monitoring and the procedure is painless. Some patients do experience rashes or itchiness around the area where the electrodes were attached but it usually resolves itself within a few hours. If you are allergic to certain adhesive materials, be sure to tell your doctor so they can make the necessary preparations. There are hypoallergenic alternatives so you should not be too worried.


In summary, Holter monitoring is a form of long-duration ECG testing that can uninterruptedly record the heart’s activity for 24 hours to 2 weeks. It is an incredibly useful test that gives your cardiologist a better idea of how your daily activities affect how your heart rhythms.

If you experience symptoms such as chest pains, palpitations, skipped heartbeats, fluttering, and unexplainable fainting spells, consult your doctor as soon as possible to ensure that your condition is diagnosed and well managed. Early diagnosis is important in ensuring effective treatment.

Dr Devinder Singh

Senior Consultant Cardiologist &
Cardiac Electrophysiologist

Dr Devinder Singh is the Medical Director of Cadence Heart Centre. He is an experienced Senior Consultant Cardiologist & Cardiac Electrophysiologist with over 20 years of clinical experience.

His expertise lies in clinical cardiology, cardiac rhythm disorders (arrhythmia), cardiac pacing (including cardiac resynchronisation therapy) and cardiac magnetic resonance imaging. He performs electrophysiology studies and radiofrequency ablation of cardiac arrhythmias, and is well versed in pacemaker and defibrillator insertions.

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    No health concern is too small. Contact us to book a consultation or comprehensive diagnosis and treatment plan.

    For urgent enquiries after office hours, please call or WhatsApp us at

    (65) 8318 9884


    Mt Elizabeth Hospital, 3 Mount Elizabeth #14-13
    Mt Elizabeth Medical Centre, Singapore 228510

    Monday - Friday: 9:00AM – 5:00PM
    Saturday: 9:00AM – 12:30PM 
    Sunday & Public Holiday: CLOSED


    No health concern is too small. Contact us to book a consultation or comprehensive diagnosis and treatment plan.

    For urgent enquiries after office hours, please call us at

    (65) 8082 1366


    Farrer Park Hospital, 1 Farrer Park Station
    Road #15-06/07 Connexion, Singapore 217562

    Monday - Friday: 9:00AM – 1:00PM | 2:00PM - 5:00PM
    Weekends & Public Hollidays: CLOSED
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