An electrocardiogram is a test that checks for problems with the electrical activity of your heart and checks your heart’s rhythm. An ECG translates the heart's electrical activity into line tracings on paper. The spikes and dips in the line tracings are called waves. A natural electrical system causes the heart muscle to contract and pump blood through the heart to the lungs and the rest of the body.
Sensors attached to the skin are used to detect the electrical signals produced by your heart each time it beats. These signals are recorded by a machine and are looked at by a doctor to see if they're unusual. An ECG may be requested by a cardiologist.
An ECG is often used alongside other tests to help diagnose and monitor conditions affecting the heart. It can be used to investigate symptoms of a possible heart problem, such as chest pain, suddenly noticeable heartbeats (palpitations), dizziness and shortness of breath.
An ECG can help detect:
How an ECG is carried out?
There are several different ways an ECG can be carried out. Generally, the test involves attaching a number of small, sticky sensors called electrodes to your arms, legs and chest. These are connected by wires to an ECG recording machine.
You don't need to do anything special to prepare for the test. You can eat and drink as normal beforehand. The test itself will normally only last a few minutes, and you can usually go home soon afterwards or return to the ward if you're already staying in hospital.
Are there any risks or side effects?
An ECG is a quick, safe and painless test. No electricity is put into your body while it's carried out. There may be some slight discomfort when the electrodes are removed from your skin – similar to removing a sticking plaster – and some people may develop a mild rash where the electrodes were attached. In case you feel stress or chest pain during the test, it can be stopped.