Timeline development of ECG

Alexander Muirhead attached wired to a feverish patient’s wrist to obtain a record of the patient’s heartbeat while studying for his doctor of science (in electricity) in 1872 by Hospital. This activity was directly recorded and visualized using a Lippnann capillary electrometer by the British physiologist John Burdon Sanderson .

The first to systematically approach the heart from an electrical point-of-view was Augustus Waller, working in St. Mary’s Hospital in Paddington, London. His electrocardiograph machine consisted of Lippmann capillary electrometer fixed to projector. The trace from the heart beat was projected onto a photographic plate which was itself to a toy train. This allowed a heartbeat to be recorded in real time. In 1911 he still saw little clinical application for his work.

British physiologists William Bayliss and Edward Starling of University College London in 1892 improved the capillary electromotor. They connect the terminals to the right hand and to the skin over the apex beat and show a “triphasic variation accompanying (or rather preceding) each beat of the heart”. These deflections are later called P, QRS, and T. They also demonstrated delay of about 0.13 seconds between trial stimulation and ventricular depolarization (later called PR interval) .

The breakthrough came when Willem Einthoven, working in Leiden, The Netherlands, used the string galvanometer which he invented in 1902, which was much more sensitive than capillary electrometer that Waller used. Einthoven assigned the letters P, Q, R, S and T to the various deflections, and described the electrocardiographic features of a number of cardiovascular disorders. In 1924, he was awarded the Nobel Prize in Medicine for his discovery.

Einthoven discussed commercial production of a string galvanometer with Max Edelmann of Munich and Horace Darwin of Cambridge Scientific Instrument Company of London in 1903. He also started transmitting electrocardiograms from Hospital to his laboratory 1.5 km away via telephone cables. On March 22^nd 1905 the first ‘telecardigram’ was recorded from a healthy and vigorous man and the tall R waves are attributed to his cycling from laboratory to hospital for recording. ECG sensor design is traditionally completed in the field of biomedical Engineering. Investigation of Biomedical Engineering represents a good starting point for a person embarking on research of ECG.