Cardiovascular Technologists

Electrocardiography can be traced back 300 years to the work of the Dutch anatomist and physiologist Jan Swammerdam, who in 1678 demonstrated that a frog's leg will contract when stimulated with an electrical current. It was not until 1856, however, that two German anatomists, Albert von Kölliker and Heinrich M. Mueller, showed that when a frog's heart contracted, it produced a small electrical current. In succeeding years, the electrical behavior of beating hearts was extensively studied, but always with the chest open and the heart exposed.

In 1887, Augustus Desiré Waller discovered that the electrical current of the human heart could be measured with the chest closed. He was able to do this by placing one electrode on a person's chest and another on the person's back and connecting them to a monitoring device. In 1903, a Dutch professor of physiology, Willem Einthoven, perfected the monitoring device so that even the faintest currents from the heart could be detected and recorded graphically.

Throughout the rest of the 20th century, medical researchers made further advancements and refinements on this machine. By the 1940s, for instance, portable electrocardiographs were in use, allowing electrocardiograms to be made in a physician's office or at a patient's bedside. During the 1960s, computerized electrocardiographs were developed to aid physicians in the interpretation of test results. Today, electrocardiographs are widely used in routine physicals, in presurgical physicals, in diagnosing disease, and in monitoring the effects of prescribed therapy. The wide use of these devices ensures a continuing need for trained personnel to operate them.