Heart test
Holter Monitor (24-hour ECG)
A Holter monitor is a portable device that records your heart’s rhythm continuously over a day or longer, to catch problems that a short ECG might miss.
Quick answer
Holter Monitor (24-hour ECG): what it is and what the results mean
A Holter monitor is a small, wearable recorder connected to chest electrodes that continuously tracks the heart’s electrical activity, usually for 24 to 72 hours or sometimes longer, during normal daily life.
- Why it is done: It is used to investigate palpitations, dizziness, blackouts or suspected irregular heart rhythms that come and go and may not show up during a brief ECG in clinic.
- Understanding results: The recording is analysed for abnormal rhythms and correlated with your symptom diary, so any palpitations or dizziness can be matched to what the heart was doing at the time.
What it is
A Holter monitor is a small, wearable recorder connected to chest electrodes that continuously tracks the heart’s electrical activity, usually for 24 to 72 hours or sometimes longer, during normal daily life.
Why it is done
It is used to investigate palpitations, dizziness, blackouts or suspected irregular heart rhythms that come and go and may not show up during a brief ECG in clinic.
What to expect
Small electrodes are stuck to the chest and connected to the recorder, which you wear as you go about your day. You keep a diary of symptoms and activities, then return the device for the recording to be analysed.
Understanding the results
The recording is analysed for abnormal rhythms and correlated with your symptom diary, so any palpitations or dizziness can be matched to what the heart was doing at the time. A specialist reports the findings.
Good to know
Risks and limitations
The test is completely safe and painless. Its main limitation is timing — if symptoms are infrequent they may not occur during the recording, in which case a longer or implanted monitor may be suggested.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Holter Monitor (24-hour ECG): frequently asked questions
Can I shower with a Holter monitor?
Usually not, as most monitors should be kept dry. You will be told how long to wear it and how to look after it, so it is best to shower before fitting and after returning it.
What if I have no symptoms while wearing it?
If symptoms are infrequent and do not occur during the recording, the test may be normal despite a real problem. Your clinician may then suggest a longer-term or implantable monitor to catch rare events.
Related tests
Other heart test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Royal College of Radiologists / relevant professional body
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