Holter ECG

What a Holter ECG is

A standard ECG lasts a few seconds and shows the heart’s rhythm only at that moment. If your arrhythmia comes once a day or once a week, the chance of catching it is small. The Holter solves exactly this problem: it is a small recorder, about the size of a small phone, connected to a few electrodes stuck on the chest. It records every heartbeat while you go on with daily life: work, walking, sleep, stress, physical activity.

The recording usually lasts 24–48 hours. When episodes are rare, longer monitoring with other recording devices may be needed. The rhythm Holter is not the same as the blood pressure Holter (ABPM), which measures blood pressure for 24 hours (see hypertension).

Why it is done

• palpitations, “skipped beats” or fast beats not caught on a standard ECG (see palpitations);
• dizziness or fainting episodes with an unclear cause;
• detecting arrhythmias that cause no symptoms, for example paroxysmal atrial fibrillation after a stroke (see atrial fibrillation);
• assessing a known arrhythmia, for example rate control in atrial fibrillation, or extrasystoles;
• assessing the effect of medicines or of a procedure;
• after a heart attack or in other heart disease, when the cardiologist wants to check the rhythm.

Preparation

Take a shower beforehand: during the recording you usually cannot wet the device. Do not apply cream or oil to your chest that day, because electrodes stick better to clean, dry skin. In men a few small areas of the chest may be shaved. Wear comfortable clothes, preferably with buttons at the front, so the cables are not pulled. Take your medicines as usual, unless your doctor has told you otherwise.

During the recording

Go on with your usual activity: the aim is to catch the complaints you have in real life, not on a day cleared of every activity. If you normally walk, work or exercise lightly, do so today as well.

Keep a diary: note the time of every symptom (palpitation, dizziness, pain), what you were doing and when you took your medicines. This helps the cardiologist link sensations to the recording, and it is often the part that makes the result useful. Some devices have a button to mark the moment of a symptom.

Do not wet the device unless you have been told the model is waterproof. Avoid strong magnetic fields, such as those of construction cutting equipment or induction cooktops held close, and do not turn it off. If an electrode comes loose or your skin becomes very irritated, contact the clinic. After the recording ends, the device is returned and the data analyzed.

Results

The cardiologist analyzes the entire recording and reports:

• the lowest, highest and average heart rate;
• premature beats (extrasystoles), their number and origin (atrial or ventricular), see heart arrhythmias;
• episodes of fast or slow arrhythmias and pauses;
• the link between complaints noted in the diary and the rhythm at that moment.

A result with some premature beats is very common in healthy people and often needs no treatment. If your complaints occurred when the rhythm was normal, that in itself is a valuable answer: the cause is not an arrhythmia. The Holter does not reliably detect all arrhythmias. If the typical episode does not happen during the recording, longer monitoring or another test may be needed.

Risks

There are no risks: the Holter only records and delivers no current. There may be mild skin irritation from the electrode adhesive, especially on sensitive skin; tell the clinic if it itches or reddens a lot. The device may slightly disturb sleep in some people, but this passes after the recording.

This information is educational and does not replace a medical visit.