Dr Simon Kennon MB ChB, FRCP, MD Consultant Cardiologist


An electrocardiogram (ECG) is a recording of the rhythm and electrical activity of the heart.

The ECG can pick up abnormal heart rhythms – both fast and slow. The ECG can pick up abnormal electrical signals due to underlying problems with the coronary arteries, heart valves and heart muscle.

What to expect

You will be asked to undress to your waist and lie down on a couch. A number of wires, that are connected to the ECG machine,are attached to your chest, legs and arms. These wires pick up the hearts electrical signals. These signals are relayed on a screen and are traced out on a piece of paper

Importantly, however, an ECG is a snapshot of the hearts rhythm and electrical activity. If you have an intermittent problem with your heart rhythm the ECG may not pick this up. In addition, problems with the heart often cause non-specific changes to the hearts electrical activity and do not allow a specific diagnosis. Thus an ECG is a useful screening test. Sometimes it can diagnose a specific problem but often other investigations are required.