ABSTRACT.The heart is a relatively simple mechanical device whose primary purpose is to circulate oxygenated and non-oxygenated blood throughout the body. Its rhythmical repetitive pumping action is initiated and maintained by a series of electrical events that can be recorded as the electrocardiogram (ECG). EEG technologists who routinely monitor this electrical event have the opportunity to watch this over a much longer period of time than the ECG technician recording a routine ECG for only a few minutes. Even though the simplified“Lead I”that is usually recorded is only a piece of the story, a great deal can be learned if a few measurements are made and the individual components are analyzed.