--- title: "ECG (electrocardiogram): What to Expect | HealthAnswers" description: "An ECG is a painless test that records your heart" url: https://healthanswers.co.uk/tests/ecg/ robots: noindex --- # ECG (electrocardiogram): What to Expect | HealthAnswers Tests & investigations An ECG is a painless test that records your heart's rhythm and electrical activity using sticky pads, helping detect arrhythmias and heart attacks. Written by HealthAnswers editorial team Medically reviewed by [HealthAnswers UK doctor review panel](https://healthanswers.co.uk/our-doctors/) Reviewed 3 July 2026 ## Quick answer What is an ECG? An ECG, or electrocardiogram, is a test that records your heart's rhythm and electrical activity using sticky pads on the chest, arms and legs, taking only a few minutes. It can detect arrhythmias, heart attacks, and problems with the heart's electrical conduction. The test is painless and can be done at a GP surgery, in hospital, or in an ambulance. ## Who is this page for? This page is for people in the UK who want a plain-English overview of ECG (electrocardiogram), including when to seek help and what NHS care usually involves. It explains general information, not what is wrong with you personally. ## Who should skip this page? Skip this page if you need a diagnosis, a prescription, or emergency care. It cannot replace a GP, pharmacist, NHS 111 or 999. If you are in immediate danger, call 999; for urgent advice that is not life-threatening, call 111 in England, Scotland or Wales, or use your GP out-of-hours service in Northern Ireland. On this page 4 sections ## Key facts about the ECG - A standard resting ECG uses 12 leads to record the heart's activity. - An ECG can detect atrial fibrillation and other abnormal heart rhythms. - Changes in the ST segment can indicate a heart attack. - A normal ECG does not rule out all forms of heart disease. - A Holter monitor records the heart's rhythm continuously over 24 to 72 hours. ## What an ECG shows An ECG tracing shows a series of electrical waves, labelled P, QRS and T, which represent the different stages of the heart depolarising and repolarising with each beat. From this tracing, doctors can assess the heart’s rate and rhythm, its electrical axis, and signs of reduced blood flow known as ischaemia. ## When an ECG is performed An ECG is commonly carried out for palpitations, chest pain, before an operation, or to monitor the effects of certain heart medicines. It is also a routine part of emergency assessment for anyone presenting with chest pain. ## Types of ECG There are several types of ECG suited to different symptoms: a resting 12-lead ECG taken at a single point in time, a Holter monitor worn for continuous recording over a longer period, an event recorder used to capture occasional symptoms, and an exercise ECG carried out during physical activity. ## What happens after an abnormal ECG result If your ECG shows an abnormality, an echocardiogram is often used to assess the heart’s structure in more detail. You may also be referred to a cardiologist if further specialist assessment is needed. ## ! When to speak to a doctor about the ECG A GP can arrange an ECG if you have palpitations, chest pain, or have fainted (syncope). Call **999** or go to A&E for severe chest pain, as an ECG can be carried out in the ambulance or at A&E as part of emergency assessment. ## Common questions about the ECG How do I prepare for an ECG? No fasting is needed before an ECG, but you will need a bare chest so that sticky pads can be attached. It is worth telling staff if you have a hairy chest, as some hair may need to be shaved so the pads stick properly. Can I have palpitations with a normal ECG result? Yes, a resting ECG only captures a snapshot of your heart's rhythm, so intermittent arrhythmias can easily be missed if they are not happening at the time. A Holter monitor or event monitor, which records over a longer period, may be needed to catch them. What is an exercise ECG? An exercise ECG, also called a stress test, monitors your heart while you walk on a treadmill. It assesses your exercise capacity and checks for signs of reduced blood flow to the heart, known as ischaemia. What happens if my ECG result is abnormal? An abnormal ECG is interpreted by a GP or cardiologist, who will explain what it means for you. You may need further tests, such as an echocardiogram, to investigate the finding in more detail. ## Sources - [NHS — Electrocardiogram](https://www.nhs.uk/conditions/electrocardiogram) - [NHS — Atrial Fibrillation](https://www.nhs.uk/conditions/atrial-fibrillation)