Medical test · Cardiovascular

Ambulatory ECG monitoring

Also known as: 24-hour ECG, ambulatory ECG, event recorder, loop recorder, patch monitor

A portable recorder worn for 24 hours to two weeks (or an implanted loop recorder for up to three years) that captures the heart's rhythm during normal life, catching the intermittent arrhythmias a ten-second ECG misses.

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Kind
Physiological or functional test
Categories
Cardiovascular
Specimen
No specimen
Method
Electrophysiological recording

What it measures

MeasureWhat it tells you
Rhythm over timeEvery beat is recorded and analysed; runs of atrial fibrillation, pauses and extra beats are counted.
Symptom correlationThe wearer presses a button or keeps a diary so symptoms can be matched to the tracing at that moment.
Heart rate rangeSlowest and fastest rates, including during sleep.

Why it is ordered

  • Palpitations that come and go
  • Unexplained blackouts or falls
  • Looking for atrial fibrillation after a stroke
  • Checking a pacemaker or drug treatment is controlling a rhythm
  • Suspected heart block

How it is done

Three to five chest electrodes lead to a small recorder on a belt, or a single adhesive patch; normal activities continue except bathing. Implantable recorders are injected under the skin of the chest.

Preparation. None; keep a symptom diary.

Reading the result

FindingUsual meaning
Palpitations coincide with atrial fibrillationDiagnosis made; consider anticoagulation and rate or rhythm control
Pause of more than 3 seconds with dizzinessSymptomatic bradycardia; likely pacemaker
Symptoms with normal rhythmPalpitations are not due to an arrhythmia; reassuring

Reference ranges vary by laboratory, method, age, sex and clinical context; a result is read against the person, not a table.

Limitations

Only useful if symptoms occur during the recording; rare events need longer monitoring or an implanted device.

Catalogued concepts this page covers

Concepts of the master test taxonomy that resolve to this page; each links to its category.

Educational content. Reference ranges differ between laboratories, methods, ages and sexes, and results are always read against the person, the question asked and other findings. This page cannot interpret an individual result.