What is an ECG machine used for?

Small sticky electrodes are placed on the chest and sometimes the limbs. Wires connect them to the machine, which produces a tracing of electrical signals as the heart beats. A clinician reviews the pattern for features such as an irregular rhythm, a fast or slow rate, or changes that may need further assessment.

An ECG is a recording at one point in time. A normal tracing does not explain every episode of palpitations, chest discomfort or breathlessness, and an abnormal tracing needs interpretation alongside symptoms and examination findings.

You usually lie still while the electrodes are attached to clean, dry skin. Wear clothing that allows access to the chest, and tell the clinician about implanted devices, skin sensitivity or difficulty lying flat. The recording itself is brief and does not send electricity into your body. Avoid talking or moving during the tracing so the signal is easier to interpret. You may be referred for an electrocardiogram as part of a wider assessment.

Seek emergency care for chest pressure or pain with breathlessness, sweating, fainting, severe weakness or pain spreading to the arm, back or jaw. Do not wait for a routine ECG appointment when these symptoms are sudden or severe.

Ask why an ECG is recommended, whether you should rest or avoid anything beforehand, and when the result will be explained. If symptoms come and go, ask whether another type of heart monitoring may be considered.