Introduction to cardiac electrophysiology and the development of cardiac pacing

The historical development of the stimulation of the heart artificially by means of an electrical impulse generated externally and introduced to the body through the skin is discussed. Later developments involved insulated wires which were passed through the skin into a vein and thence passed via the right atrium to the right ventricle. The same principles are still employed for temporary pacing today. Development of the first fully implantable pacemaker is then examined as well as trends in ventricular demand pacing and rate adaptive devices. The most recent advances lie in ability of some pacemakers automatically to measure their own pacing capture thresholds and to adjust their outputs accordingly, thereby reducing current drain and increasing longevity still further.