Ambulatory Continuous Monitoring
Holter Monitoring
Holter monitoring records the heart’s electrical activity continuously over an extended period while you go about normal daily activities.
On this page
Understanding the test
What Is Holter Monitoring?
Holter monitoring is a form of ambulatory ECG monitoring. A small portable recorder is connected to electrodes on the chest and records the heart’s electrical activity continuously.
Because the recording continues during daily activities, it can capture rhythm changes that come and go. A standard ECG lasts only a short time and may not catch them.
This is why intermittent symptoms may need a longer recording than a standard ECG.
Clinical reasons
Why Is It Used?
A Holter may be suggested when the rhythm needs to be looked at over time. Common reasons include:
- Palpitations that come and go
- Suspected intermittent arrhythmias
- Rhythm-related symptoms that are not explained
- Assessing how often extra beats occur
- Evaluating the rhythm over time
Not every symptom needs a Holter. Your doctor decides whether it is useful in your situation.
The system
How It Works
The test is a simple chain from the skin to the clinician.
Electrodes
Placed on the chest to pick up the heart’s electrical signals.
Recorder
A small portable device stores the signals.
Continuous rhythm data
The rhythm is recorded throughout the monitoring period.
Clinical review
The recording is analysed and reviewed by a doctor.
Practical points
Wearing the Monitor
Electrodes are attached to the chest and connected to a portable recorder, which is carried or worn on the body.
Where appropriate you continue your normal daily activities. It helps to keep the equipment in place and to follow the instructions you are given for your recording.
Instructions can differ between devices and individual circumstances, so follow the guidance provided to you.
What is recorded
What Does It Record?
The recording shows the heart rate and rhythm over the monitoring period.
Heart rate
How the rate changes over the period.
Rhythm
Whether the rhythm is regular or irregular.
Premature beats
Early beats from the upper or lower chambers.
Fast rhythms
Episodes of tachyarrhythmia, where present.
Slow rhythms
Episodes of bradyarrhythmia, where present.
Pauses
Pauses in the rhythm, where present.
A Holter does not on its own give every diagnosis. It is interpreted with the rest of the assessment.
Symptom correlation
Symptom Diary and Event Correlation
Writing down when symptoms occur helps to match them with the recorded rhythm.
Notice a symptom
Note what you feel.
Record the time
Write down when it started and how long it lasted.
Note the activity
What you were doing at the time.
Compare with the recording
The doctor compares your entries with the rhythm at those times.
Comparison
Standard ECG vs Holter
The two tests serve different purposes. Neither is better than the other.
Short recording
Standard ECG
A recording made at a specific moment, usually lasting a short time.
Useful for looking at the rhythm and heart pattern at that moment.
Extended recording
Holter
Continuous rhythm monitoring over a longer period during daily life.
Useful when the rhythm changes over time or symptoms come and go.
Comparison
Holter vs Event Recorder
Both are forms of ambulatory monitoring, but they are designed differently, and device types vary.
Holter
Records continuously throughout its monitoring period.
Event-oriented monitoring
Designed for longer-term or event-based capture, depending on the type of device.
Choice of test
Depends on how often symptoms occur and what question needs to be answered.
Event recording is described in the diagnostics overview.
Interpretation
Results
After the recording period the data is analysed and reviewed by a doctor. The review may look at:
- The rhythm over the whole period
- Heart rate trends
- The number and pattern of extra beats
- Recorded events
- Correlation with symptoms from your diary
The findings are interpreted in the context of your symptoms, history and other tests.
The result may reassure, may suggest further tests, or may help to guide treatment.
Clinical context
Rhythm Disorders Where Holter Monitoring Can Help
Holter monitoring can provide information in several rhythm conditions, where clinically relevant.
Looking for an irregular rhythm that comes and goes.
Recording episodes of fast rhythm that start above the ventricles.
Counting extra beats and seeing their pattern over time.
Looking for runs of fast ventricular rhythm.
The overview of ventricular rhythm disorders.
Questions