There are many medical supplies that can be found online, one of which is the ecg machine.  The ecg machine is a very important medical device that is used to record the electrical activity of the heart over time. Examination of the various waves and normal vectors of depolarization and repolarization yields important diagnostic information.  The ECG has become so familiar to the general population that it is part of the logo of many medical organisations, representing the technical side of medicine vs. the Rod of Asclepius or caduceus, which are more traditional.

Being an electrical representation, it signifies vitality and urgency. In various television medical dramas, an isoelectric ECG (no cardiac electrical activity, also known as flatline) is often used as a symbol of death or at least extreme medical peril. This is technically known as asystole, a form of cardiac arrest with a particularly bad prognosis. Though sometimes shown on television, defibrillation, which can be used to correct arrythmias such as ventricular fibrillation and pulseless ventricular tachycardia, cannot correct asystole.

The ecg machine has a rich history that has lead to its prominent future.  In 1856 Kollicker and Mueller discovered the electrical activity of the heart when a frog sciatic nerve/gastrocenemius preparation fell onto an isolated frog heart and both muscles contracted synchronously.

Alexander Muirhead attached wires to a feverish patient's wrist to obtain a record of the patient's heartbeat while studying for his DSc (in electricity) in 1872 at St Bartholomew's Hospital. This activity was directly recorded and visualized using a Lippmann 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 a Lippmann capillary electrometer fixed to a projector. The trace from the heartbeat was projected onto a photographic plate which was itself fixed 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. The breakthrough came when Willem Einthoven, working in Leiden, The Netherlands, used the string galvanometer invented by him in 1901.

This was much more sensitive than the 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.