Holter Monitor Test in Singapore: How It Works, Wearing It and 24-Hour vs 7-Day Monitoring

Medically reviewed by Dr Reginald Liew - Senior Consultant Cardiologist, The Harley Street Heart & Vascular Centre. Medically Reviewed on: 15/07/2026

A Holter monitor is a small, portable device that records your heartbeat continuously while you go about your normal day. It is one of the most useful tools for investigating palpitations, dizziness or a suspected irregular heart rhythm, because it captures what your heart is doing over hours or days rather than in the few seconds of a standard ECG. This guide explains what a Holter monitor detects, how to prepare and wear it, when you get results, and how the 24-hour, 48-hour, 7-day and patch options differ. It is general information and not a substitute for advice from your own doctor.

What Is a Holter Monitor?

A 24-hour Holter monitor provides a continuous recording of the electrical activity of your heart - both rate and rhythm - over 24 hours. It is a safe, painless recording made using a small monitor attached to your chest with electrodes, worn while you carry out your normal daily activities. It is used to link symptoms such as dizziness, breathlessness or palpitations with what the heart's electrical activity is doing at that moment, and to assess how well medication is working.

What Does a Holter Monitor Detect?

A Holter monitor can help detect and assess:

• Heart palpitations (skipped, fluttering or racing beats)
• Unexplained dizziness, near-fainting or fainting
• Suspected atrial fibrillation, particularly the intermittent (paroxysmal) form
• Suspected ventricular arrhythmias
• A slow heart rate (bradycardia) and conduction blocks
• Pacemaker or defibrillator function
• Hidden atrial fibrillation as part of a stroke work-up
• The effectiveness of anti-arrhythmic medication

A common question is whether a Holter monitor will show palpitations. It records every heartbeat while it is worn, so if palpitations occur during the recording, they will be captured - which is why keeping a symptom diary is so useful. If symptoms are infrequent, a longer recording period may be needed to catch them.

Holter Monitor vs ECG: What's the Difference?

A standard ECG records your heart's electrical activity for just a few seconds in the clinic. A Holter monitor records the same kind of information, but continuously over 24 hours or longer while you go about your day. This makes the Holter far more likely to capture intermittent problems - an irregular rhythm that comes and goes may simply not be present during the few seconds of a resting ECG. A Holter is also different from hospital telemetry: a Holter records onto the device for later analysis as an outpatient, whereas telemetry is continuous live monitoring of an inpatient in hospital.

How to Prepare for Your Holter Monitor

• Shower before your appointment - the standard monitor cannot get wet once it is fitted.
• Avoid lotions, creams, oils or powders on the chest, as these stop the electrodes sticking.
• Men with significant chest hair may have small patches shaved so the electrodes stay attached.
• Wear a loose two-piece outfit.
• Bring a list of your current medications.
• Fitting takes about 15 to 20 minutes.

What to Do While Wearing the Monitor

• Continue your normal daily activities - the aim is to record an ordinary day.
• Keep a symptom diary, noting the time and nature of any symptoms; this is essential for interpretation.
• Do not bathe or swim (sponge baths are fine for the standard monitor); you can take a light shower with a patch Holter.
• Avoid magnets, metal detectors where possible, and MRI scans.
• Phones and household appliances do not interfere with the recording.
• If an electrode loosens, contact the clinic - do not try to reattach it yourself.

After 24 Hours: Returning It and Getting Results

At the end of the recording period, you return the monitor and your symptom diary to the clinic; removal takes only a few minutes. The recording is then analysed by specialist software and reviewed by a cardiologist, who interprets it alongside your diary. Results are typically available within 3 to 7 days.

24-Hour vs 48-Hour vs 7-Day vs Patch Monitor: Which Do You Need?

The right monitor depends on how often your symptoms occur and what is suspected:

• 24-hour Holter: Suitable when symptoms occur most days. It captures a full day and night of heartbeats.
• 48-hour Holter: Extends the window when daily symptoms are slightly less frequent.
• 7-day or 14-day monitor: Used when symptoms are intermittent; a longer recording gives a better chance of catching an occasional arrhythmia such as paroxysmal atrial fibrillation.
• Patch monitor: A small adhesive patch worn for several days; many patch monitors are waterproof, which makes longer wear more comfortable.
• Implantable loop recorder: For very infrequent but important symptoms, a small device can be placed under the skin to monitor for months. This is arranged when shorter monitoring has not captured the problem.

In short, the longer your symptoms take to appear, the longer the recommended monitoring period.

Are There Any Risks?

Holter monitoring is non-invasive, painless and very safe. The most common side effect is mild skin irritation under the electrodes. There is no radiation, injection or anaesthetic involved.

Frequently Asked Questions

Will a Holter monitor show palpitations?

Yes - it records every heartbeat while worn, so palpitations that occur during the recording are captured. Note them in your symptom diary so the cardiologist can match them to the trace. If they are infrequent, longer monitoring may be advised.

Why would I need to wear a heart monitor for 7 or 14 days?

Longer monitoring is used when symptoms come and go. A 24-hour recording may miss an arrhythmia that only appears occasionally, so a 7-day, 14-day or patch monitor gives a better chance of catching it.

Can I shower with a Holter monitor on?

Not with the standard 24-hour monitor - it is not waterproof, so use sponge baths. You can take a light shower with a patch Holter, as patch monitors are typically waterproof.

What if I have no symptoms during the recording?

The monitor still records every heartbeat and can detect silent abnormalities. If your symptoms are infrequent, your cardiologist may recommend extended monitoring.

Is a Holter monitor the same as an ECG?

It records the same kind of electrical information as an ECG, but continuously over a day or more rather than for a few seconds, which makes it better at catching intermittent rhythm problems.

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