Ambulatory ECG Monitoring (Holter)

To better understand your symptoms, visit us for a comprehensive diagnosis and personalised treatment plan.

What is an Ambulatory ECG (Holter) monitor?

Usually referred to simply as a Holter monitor, it is a machine used to continuously monitor your heart’s rate and rhythm over a period of 24 hours or more. Within this time, electrodes are attached to your chest with a small recording monitor. Advancements in technology have produced Holter monitors that are more lightweight, smaller and more comfortable.

What is it for?

A Holter test is done to monitor your heart’s electrical activity on a day-to-day basis. With the Holter monitor, your doctor could monitor and capture any abnormalities on ECG over a longer period of time during normal activity, while you’re at rest and also while physically active.

Why would I need a Holter test?

Your doctor may send you for a Holter test if you experience:

  • Palpitations (or feeling of irregular heartbeat)
  • Dizziness
  • Fainting spells
  • Shortness of breath
  • Chest pain
  • Unexplainable fatigue

Additionally, a Holter test can assist in the diagnosis of various cardiovascular diseases, including:

  • Atrial fibrillation/ flutter
  • Tachycardias (supraventricular or ventricular)
  • Bradycardias and heart blocks
  • Ectopic beats (atrial or ventricular)
How accurate is a Holter test?
Ambulatory ECG Holter

A normal ECG is usually performed over 30 seconds at rest in the doctor’s clinic. A Holter test records the ECG continuously over a prolonged period of time, outside of the clinic setting. It can detect abnormalities in your heart’s electrical activity on ECG which will otherwise be missed on a normal ECG. The Holter records more accurately the ECG during day-to-day activities.

To ensure that the data recorded by the Holter monitor is accurate, make sure to keep the monitor and electrodes secure to the body.

How should I prepare for this test?

Before the test, do inform your doctor if you are allergic to adhesive materials as these will be used to attach the electrodes to your body. Throughout the test, you should also ensure that the electrodes are securely placed so that the monitor can get an accurate recording.

What can I expect during a Holter test?

At Capital Heart Centre, we utilise a patch electrode Holter monitor. This allows for easier attachment and a more comfortable experience as only an adhesive device will need to be attached to your chest area.

During your appointment, the patch electrode Holter monitor will be attached to you. This usually takes 30 seconds and is completely painless.

During the test

You will be asked to go about your daily activities as you normally would, including exercising and showering. You will wear the device for the length of time requested by your cardiologist. Then, return the device at the end of the test, as instructed.

You are advised to:

  • Wear loose-fitting and comfortable clothing
  • Continue taking the medications prescribed to you, unless stated otherwise
  • Continue with all day-to-day activities, including showers and exercise

Please note that if you experience symptoms such as palpitations or dizziness, the patch Holter monitor has a function that allows you to indicate the time of the symptom. Your cardiologist may also provide you with a diary sheet to accurately record symptoms that you experience.

Ambulatory ECG Capital Heart Centre

After the test

  • After the test duration, the electrodes and monitor will be removed, and the data will be downloaded for analysis.
What would affect the results of a Holter test?

Faulty or incorrect readings may occur if the Holter monitor is exposed to:

  • Electrode patch coming loose
  • Electrical interferences and powerful magnets
What can you not do while wearing a Holter monitor?

To avoid getting an incorrect reading which would require you to repeat the whole test, you should avoid:

  • Extremely vigorous exercises and activities resulting in dislodgement of the electrode and monitor.
  • Going for X-ray investigations

When you come for the test, your cardiologist will provide you with further instructions. If you have any concerns, please ask your cardiologist.

Can I use my phone during a Holter test?

Yes. You can continue using your phone, laptop, or tablet as you proceed with the test.

Are there any risks or side effects to wearing a Holter monitor?

Ambulatory ECG (Holter) monitoring is a non-invasive test that is very safe. There are no major risks or side effects associated with it, apart from slight itching or discomfort for those with sensitive skin. There is no electricity going through the electrodes or monitor. If you ever experience any discomfort during or after the test, do inform your cardiologist.

How can we help you?

We offer consultation for a comprehensive range of cardiac diagnostic tests and treatment plans.

Dr Joshua Loh

Senior Consultant Interventional Cardiologist

Medical Director at Capital Heart Centre, Dr Joshua Loh has more than 15 years of experience in the field of cardiology.

He has extensive experience in the treatment of complex coronary and interventional procedures.



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