What Is an ECG Machine Used For?

An ECG machine is used to record the heart’s electrical activity and help check its rate, rhythm and response to possible heart problems. It converts signals detected by adhesive electrodes on the skin into a tracing that a trained clinician can interpret. The test may be requested when symptoms such as palpitations, chest discomfort, breathlessness or dizziness need assessment, or as part of a planned health check before a procedure.

An ECG can show whether the heartbeat is regular, how quickly it is beating and how electrical signals travel through the heart. Certain patterns may give clues about an irregular rhythm, a previous heart injury, changes in the heart muscle or reduced blood flow. The tracing is one part of an assessment: an ECG can look normal even when symptoms need further investigation, and an unusual tracing does not by itself establish the cause. Your clinician may combine it with your history, examination, blood tests or imaging.

You usually lie still while electrodes are placed on the chest and sometimes the arms and legs. Skin may be cleaned first, and hair may need trimming so the electrodes stay attached. Keep your body relaxed and avoid talking or moving during the recording, because muscle movement can affect the tracing. Tell the clinician about medicines, an implanted device, skin sensitivity or difficulty lying flat. After the electrodes are removed, you can generally return to your usual activities unless your care team gives different advice.

Seek emergency help for chest pressure or pain that is severe, persistent or spreading to the arm, back, neck or jaw, especially with sweating, nausea, fainting or difficulty breathing. Do not wait for an ECG appointment if you have severe breathlessness, collapse, or a fast or irregular heartbeat with weakness, chest discomfort or faintness. An ECG is an assessment tool and should not delay urgent evaluation of new or worsening symptoms.

Ask what the ECG is intended to investigate, whether you should take your usual medicines beforehand, and when you will receive the interpretation. If symptoms come and go, ask whether a longer period of monitoring could be more informative than a recording taken during a symptom-free moment.