Introduction
An electrocardiogram, or ECG, is a quick, painless test using small stickers on the chest and limbs. It provides a snapshot of the heart rhythm and can identify many rhythm abnormalities.
What the test can and cannot show
An ECG can identify the rhythm at the time it is recorded and may show clues to rhythm disorders, conduction changes, previous heart damage or other electrical patterns. It is often the right first test because it is quick and immediately useful.
A normal ECG does not exclude a problem that happens only occasionally. If symptoms are intermittent, a monitor or another test may be more likely to capture the answer.
Key points
- It usually takes only a few minutes to record.
- A normal ECG does not always exclude an intermittent rhythm problem.
- A longer rhythm monitor may be more useful if symptoms come and go.
Patient note
“The ECG is most helpful when we interpret it alongside your symptoms and history, rather than in isolation.”
Questions about your ECG
Was the ECG recorded during symptoms? Does it show a rhythm issue? Would a longer recording answer the question better?
FAQ
Do I need to prepare for an ECG?
Usually no preparation is needed. You may be asked to remove clothing from the upper body so the electrodes can be placed accurately.