An ECG records the electrical signals that drive each heartbeat, viewed from twelve directions. It is quick, painless and one of the most useful first tests in cardiac assessment.
What it shows
- Heart rhythm, including atrial fibrillation and other irregular rhythms
- Evidence of a current or previous heart attack
- Reduced blood supply to the heart muscle
- Thickening or enlargement of the heart chambers
- Effects of electrolyte disturbance or certain medicines
The test
Ten sticky electrodes are placed on your chest, arms and legs, and the recording takes seconds. You will need to expose your chest and lie still and quiet; shivering or talking blurs the trace. Some chest hair may need shaving for the electrodes to stick. No preparation is needed.
Important
A normal ECG does not rule out heart disease, and an abnormal one does not always mean disease is present. It is interpreted alongside your symptoms and examination.
