What should you know about an ECG scan machine?

Small adhesive electrodes are placed on the chest and often the limbs. Wires carry signals to the machine, which displays and prints a tracing. The recording reflects the timing and pattern of heartbeats; it does not take a picture of the heart or measure every aspect of heart health. A clinician interprets the tracing alongside your symptoms, examination and medical history.

The test may be requested for palpitations, chest discomfort, breathlessness, dizziness, fainting, or before some treatments. A normal tracing is useful, but symptoms that come and go may not occur during a short recording and can require a different monitor.

Wear clothing that allows access to your chest and avoid applying creams or oils beforehand, because they can loosen the electrodes. Tell the clinician if your skin is sensitive or if removing adhesive has caused problems before. You usually lie still, relax, and breathe normally for a brief recording. The procedure does not send electricity into your body. You can generally return to normal activities immediately unless your clinician gives other advice.

Seek urgent medical help for chest pressure or pain that is severe, persistent or spreading, especially with sweating, nausea, fainting or marked breathlessness. Get prompt assessment for a new irregular heartbeat with weakness, dizziness or loss of consciousness. An ECG appointment should not delay emergency care when symptoms are happening now.

Ask what the recording was checking, whether your symptoms were present during it, and whether you need repeat monitoring or another test. You can also ask how to report future palpitations and whether medicines, caffeine or exercise could affect the result.