Patient Guide

24-hour Ambulatory ECG Monitoring Test

What Is a 24-hour Ambulatory ECG Monitoring Test?

An electrocardiogram (ECG) is a recording of the heart's electrical activity.

A 24-hour ambulatory ECG monitoring test, also called the Holter monitoring test, records heartbeats over an entire day so that as many as 100,000 heartbeats are recorded by a recorder worn by the patient.

In contrast, routine ECGs record your heartbeats over a period of 10 seconds.

These ECG records are then analysed to look for any abnormalities in heart rhythm and rate.

Why Do I Need This Test?

Prolonged monitoring is ideal for detecting intermittent heart rhythm abnormalities. Specifically, it studies the impact of different activities at various times of the day on the heart rhythm or simply obtaining more detailed information about the heart's behaviour.

It may be used to check whether abnormal heart rhythm or rate could be the cause of symptoms such as giddiness, fatigue, palpitations, shortness of breath, chest pain or a fainting spell, so that the right treatment can be given.

What Can I Expect for the Test?

  1. A few electrodes will be attached to your chest and connected to a portable recorder usually worn at the waist for 24 hours. To ensure that a clear recording is obtained, some body hair may be removed from where electrodes are placed. Setting up the test equipment generally takes 20 to 30 minutes in the Non-Invasive Cardiac Laboratory.
  2. As the procedure is done on an outpatient basis, once the recorder is fitted, you can leave the hospital and carry out your usual activities, except that you should not bathe, swim or engage in activities that will wet the equipment. These activities may cause the electrodes to be disconnected or damage the recorder.
  3. Your doctor may ask you to perform activities that have triggered your symptoms before.
  4. The cardiac technologist fitting your recorder will provide you with a diary sheet to record your activities and any symptoms you may experience during the test. Accurate interpretation of your ECG recording depends on the detailed recordings in your diary. It is useful to know how your ECG looks like when symptoms appear.
  5. On your return to the hospital the following day, the recorder will be removed and data will be transferred to the computer for analysis.

Preparing for a 24-hour Ambulatory ECG Monitoring Test

On the day of the test, have a bath before coming in loose clothing to our Non-Invasive Cardiac Laboratory.

Ladies are advised to come in a two-piece blouse and skirt/pants outfit.

What Are the Potential Risks?

There are no major side effects associated with this test.

However, some people may develop itch and rash over the areas where the electrodes are attached. Please inform the technologist or doctor should you experience these problems.

When Will I Know the Results?

The results and the next step of your treatment will be discussed at the next outpatient clinic appointment with your doctor.

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