Ecg Research Paper

y of ecgA (not so) brief history of electrocardiography.
Find out how electrocuting chickens (1775), getting laboratory assistants to put their hands in buckets of saline (1887), taking the ECG of a horses and then observing their open heart surgey (1912), induction of indiscriminate angina attacks (1931), and hypothermic dogs (1953) have helped to improve our understanding of the ECG as a clinical tool. And why is the ECG labelled PQRST (1895)?

1600

1646
Sir Thomas Browne, Physician, whilst writing to dispel popular ignorance in many matters, is the first to use the word 'electricity'. Browne calls the attractive force "Electricity, that is, a power to attract strawes or light bodies, and convert the needle freely placed". (He
present itself in the form of an abrupt onset of fibrillar contraction ... The cardiac pump is thrown out of gear, and the last of its vital energy is dissipated in a violent and prolonged turmoil of fruitless activity in the ventricular walls." He also describes the electrical stimulation of the heart in cases of "fatal syncope" in man. "A single induction shock readily causes a beat in an inhibited heart, and a regular series of induction shocks (for example, sixty or seventy per minute) gives a regular series of heartbeats at the same rate." McWilliam JA. Cardiac Failure and Sudden Death. Br Med J 1889;1:6-8. McWilliam JA. Electrical stimulation of the heart in man. Br Med J 1889;1:348�50.
1890
GJ Burch of Oxford devises an arithmetical correction for the observed (sluggish) fluctuations of the electrometer. This allows the true waveform to be seen but only after tedious calculations. Burch GJ. On a method of determining the value of rapid variations of a difference potential by means of a capillary electrometer. Proc R Soc Lond (Biol) 1890;48:89-93
The four deflections prior to the correction formula were labelled ABCD and the 5 derived deflections were labelled PQRST. The choice of P is a mathematical convention dating from Descartes (as used also by Du Bois-Reymond in his galvanometer's 'disturbance curve' 50 years previously) by using letters from the second half of the alphabet. N has other meanings in mathematics and O is used for the origin of the Cartesian coordinates. In fact Einthoven used O ..... X to mark the timeline on his diagrams. P is simply the next letter. A lot of work had been undertaken to reveal the true electrical waveform of the ECG by eliminating the damping effect of the moving parts in the amplifiers and using correction formulae. If you look at the diagram in Einthoven's 1895 paper you will see how close it is to the string galvanometer recordings and the electrocardiograms we see today. The image of the PQRST diagram may have been striking enough to have been adopted by the researchers as a true representation of the underlying form. It would have then been logical to continue the same naming convention when the more advanced string galvanometer started creating electrocardiograms a few years later. (For more on Descartes see Henson JR. Descartes and the ECG lettering series. J Hist Med Allied Sci. April