Electrocardiogram function

Each heartbeat produces a small electrical signal. Adhesive sensors detect that signal from the skin, and the ECG machine displays it as a sequence of waves. Clinicians examine the spacing, shape and regularity of those waves to assess rate and rhythm. This can support evaluation of palpitations, fainting, chest discomfort and breathlessness, including concerns such as Atrial Fibrillation or Angina.

An ECG is a snapshot, so it may not capture an abnormal rhythm that comes and goes. It also cannot explain every cause of symptoms on its own. The reading is considered with your examination, history and other tests; changes can sometimes be linked with Heart Failure or other cardiac strain.

Before the appointment, list your medicines, symptoms and any implanted cardiac device. Wear clothing that permits sensor placement and avoid creams on the relevant skin. During the test, relax, keep still and mention chest discomfort, dizziness or palpitations. Ask the clinician whether a resting ECG answers the question or whether activity testing or longer monitoring would be more informative.

Get emergency help for severe or persistent chest pain, serious breathing difficulty, fainting, collapse, or a rapid irregular heartbeat accompanied by dizziness or weakness. Testing should not delay emergency treatment. For recurrent but settled symptoms, arrange a GP Consultation and bring a record of when episodes happen and what you were doing.

Which symptom or concern is the ECG assessing? What do the rate and rhythm show? Could a short recording miss an intermittent problem? Would another type of monitoring help, and how will I receive the result?