Electro-cardiogram

To date, the most common tool for clinical assessment of cardiac electrical function is the electro-cardiogram (ECG). It is a dynamic representation, usually obtained from the body surface, of the changes in cardiac electrical behaviour. 

The electrical activity produced by either the depolarization or the repolarization of myocardial tissue, specifically the nerve fibre cells, may be identified conveniently by the help of suitable electrodes and this may be plotted as a graph showing intensity (mV millivolts) along the Y-axis and time (seconds) along the X-axis, as shown in Fig. 12.1(a), also known as the electro-cardiogram (ECG). 

Bazett, H.C., An analysis of time relations of electro-cardiograms. Heart, 1920, 7 353-370. 

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