24-hour ECG (Holter)

24-hour ECG (Holter) is a monitoring test that records a specific body signal continuously or intermittently over an extended period, rather than at a single moment in time. This gives doctors a much fuller picture than a brief in-clinic reading can, particularly for symptoms that come and go. The exact duration and what's recorded depends on what your doctor is trying to capture.

It's typically used when symptoms are intermittent or unpredictable, making them hard to catch during a single short appointment. It helps doctors correlate what you're feeling with what's actually happening physiologically at the time. Your doctor will explain what specific pattern or event they're hoping to capture.

Preparation is usually minimal — you'll typically be shown how to wear or use the monitor and given instructions on what to do (or avoid) during the monitoring period. You may be asked to keep a diary of symptoms or activities alongside the recording. Following the specific instructions given helps ensure the results are as useful as possible.

You'll generally be able to continue with most normal daily activities while the device records in the background. You may be asked to avoid certain things, such as bathing with the device on, depending on the type used. Staff will give you clear instructions on what's allowed and what to note down.

Most monitoring devices are lightweight, non-invasive and designed to be worn comfortably for the required period, with only mild skin irritation being a possible minor issue for some people. Serious risks are very rare with this type of monitoring. Let the clinic know if you experience any discomfort so they can adjust the device if needed.

Once the monitoring period ends and the device is returned or downloaded, the data usually takes a few working days to be analysed and reported by a specialist. More complex or lengthy recordings may take slightly longer to fully interpret. The clinic will confirm the expected timeframe when you're set up with the monitor.

A specialist will review the recording and explain any findings in the context of your symptoms and history. Not every abnormal reading requires treatment — some are common and harmless, while others may need further investigation or follow-up. You'll be talked through what, if anything, needs to happen next.

This type of monitoring is generally available on the NHS, though there can be a wait for referral, the monitoring period itself, and result review. Private providers can typically arrange monitoring within days and often provide quicker specialist review of the results. Cost for private monitoring varies by provider.

This is a well-established and clinically reliable way of capturing patterns that a single snapshot reading would miss. Accuracy depends partly on the monitor being worn correctly and consistently for the recommended period. Your clinic will explain how to get the most useful recording from your monitoring period.

You can typically arrange this directly with a private clinic, often without needing a GP referral, with fitting appointments usually available within days. The clinic will explain how the device works, how long you'll wear it, and when to expect your results. Contact the clinic to check current availability.