Final answer:
An electrocardiogram (ECG or EKG) is an essential clinical tool that records the heart's electrical activity. The three-lead system, which tracks the lead II potential, is a traditional technique for basic cardiac monitoring. Advances include the 12-lead ECG and Holter monitors for continuous observation.
Step-by-step explanation:
An electrocardiogram (ECG), sometimes referred to as an EKG, provides a graphical representation of the heart’s electrical activity. Each 'lead' in an ECG represents a particular viewpoint from which the heart’s activity can be analyzed. Historically, a three-lead system was commonly used and involved placing electrodes on the left and right arms and the left leg. This basic electrode placement technique records the heart's electrical signals, and the voltage between the right arm and the left leg is known as lead II potential, commonly used in monitoring heart function.
Modernity offers an advanced form of this tool, the 12-lead ECG, which utilizes ten electrodes placed on the patient's chest and limbs. Despite the evolution to monitors with more leads, the three-lead system remains fundamental in understanding electrocardiography and is essential for rudimentary heart monitoring. The lead II potential is often graphed for a clear view of the heart's electrical coordination with arterial blood pressure. Moreover, Holter monitors represent an evolution in this field, as they allow for continuous ambulatory electrocardiographs and provide continuous monitoring of heart electrical activity.