Electrocardiograms

Recording the electrical activity of the heart

Electrocardiography (ECG or EKG) is the recording of the electrical activity of the heart. This noninvasive procedure produces a recording called an electrocardiogram (also ECG or EKG).

An ECG measures the heart’s electrical conduction system. It picks up electrical impulses generated by the polarization and depolarization of cardiac tissue and translates into a waveform. The waveform is then used to measure the rate and regularity of heartbeats, as well as the size and position of the chambers, the presence of any damage to the heart, and the effects of drugs or devices used to regulate the heart, such as a pacemaker.

Most ECGs are performed for diagnostic or research purposes on human hearts, but may also be performed on animals, usually for diagnosis of heart abnormalities or research.