24-hour ECG (Holter monitoring) explained
A 24-hour ECG, also known as Holter monitoring, is a heart rhythm test used to record your heart’s electrical activity continuously over a day or longer. It is commonly recommended when symptoms come and go and are unlikely to be captured during a short ECG in clinic.
This page explains why 24-hour ECG monitoring is used, what it involves, and how results are interpreted, written from a GP perspective.
These articles are intended as educational sources, not diagnostic nor taking place of a proper medical assessment. If you need help, please book an appointment with one of our GP’s.
What is a 24-hour ECG used for?
A 24-hour ECG is designed to detect intermittent heart rhythm problems that may not be present during a standard ECG.
It is commonly used to investigate:
- palpitations or awareness of heartbeat
- dizziness or lightheadedness
- blackouts or near-fainting episodes
- unexplained chest symptoms
- suspected arrhythmias
- monitoring known heart rhythm conditions
How does the test work?
Most people find the test straightforward and non-invasive.
You should expect:
- no pain during monitoring
- mild skin irritation from electrodes in some cases
- advice to avoid bathing or showering while wearing the device
You can usually work, walk, and sleep as normal.
Is a 24-hour ECG safe?
24-hour ECG monitoring is very safe and does not involve radiation or electrical shocks.
There are no significant risks. Rarely, mild skin irritation may occur where electrodes are attached.
What happens after the test?
After monitoring:
- the device is returned for analysis
- recordings are reviewed by trained clinicians
- results are interpreted alongside symptoms
Possible outcomes include:
- normal heart rhythm, which is reassuring
- benign rhythm changes requiring no treatment
- arrhythmias that may need further assessment or treatment
Abnormal results do not always mean serious heart disease.
When to seek GP review
You may wish to speak to a GP if:
- you are unsure why monitoring has been recommended
- symptoms are worrying or worsening
- you have existing heart conditions
- you need help understanding results
- you want to discuss private or faster testing options
A GP can place results into context and advise on appropriate next steps.
How AccessGP can help
AccessGP offers GP consultations to support patients undergoing cardiac investigations, including:
- assessing palpitations and cardiac symptoms
- advising whether ECG monitoring is appropriate
- reviewing and explaining ECG results
- arranging private investigations where suitable
- coordinating follow-up or referral if needed
Related articles
Further Reading and Hub Links
Visit our Medical Investigations hub or browse more health topics in the AccessGP Knowledge Base.
If you are seeking advice on appropriate investigations or referral, speak to a GP today.
Last reviewed by Dr Zamiel Hussain, GMC registered GP
Updated: 4 January 2026