ECG (electrocardiography) is used to record the electrical activity of the heart. The procedure is frequently used to diagnose abnormal heart rhythms and to investigate the cause of chest pain. Several electrodes are attached to the skin to transmit the electrical activity of the heart to an ECG machine. Several traces are produced at the same time. Each trace shows electrical activity in different areas of the heart. The test usually takes several minutes to complete and is safe and painless.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.