Electrocardiogram (EKG) is a noninvasive test, holding that gives valuable information about the state of the heart. The essence of this method is to record electrical potentials that arise during the work of the heart and in their graphical representation on screen or paper. It is the graphical representation of the electrical activity of the heart, obtained with an electrocardiograph as a treadmill. It is the main instrument of cardiac electrophysiology and has a significant role in screening and diagnosis of cardiovascular diseases, metabolic disorders and susceptibility to sudden cardiac death. It is also useful to know the duration of the cardiac cycle .We will discuss about history of EKG, why do we do EKG, why do some individuals require an exercise for EKG.
History of electrocardiography (EKG)
The presence of electrical phenomena in the contracting heart muscle was first discovered by two German scientists: R. Kolliker and J. Muller in 1856. They have conducted studies on various animals, working on open-heart surgery. However, the possibility of studying the electrical impulses of the heart was missing until 1873, when it designed in the electrometer, the instrument made it possible to register the electric potentials. As a result, improvement of the device the opportunity to record signals from the body, which allowed the British physiologist A. Waller first to get a record electrical activity in human myocardium. He first formulated the basic concepts of electrophysiology EKG, suggesting that the heart is a dipole, i.e. a combination of two electric charges of equal magnitude but opposite in sign, located at some distance from each other. Waller and belongs to a concept such as electrical axis of heart, which will be discussed below (Wagner & Marriott, 2002).
The first, who brought the EKG of the walls of laboratories in general medical practice, was a Dutch physiologist, Professor Willem Einthoven University of Utrecht. After seven years of hard work, on the basis of invented D. Shveyggerom string galvanometer, Einthoven developed the first electrocardiograph. In this device, an electric current from electrodes placed on the surface of the body, passed through a quartz fiber. The thread was located in the field of the electromagnet and vibrated when passing a current through it interact with the electromagnetic field. The optical system focuses the shadow of the filament in the light-sensitive screen, which recorded its rejection. The first EKG was very cumbersome installation and weighed about 270 kg. His services were employed five staff. Nevertheless, the results obtained Eythovenom were revolutionary. Eythoven have suggested that the electrodes on the hands and feet, which is used to this day. He introduced the concept of abstraction, offering three so-called standard limb leads, i.e., measurement of potential difference between the left and right arm abduction I), between the right arm and left leg lead II) and between the left arm and left leg abduction III). Merit Einthoven was appreciated; and in 1924, he awarded the Nobel Prize (Masters& Martin, 2003).
In the twenties of the last century, Goldberger suggested that ...