What is today known as the EKG (alternately ECG) or "electrocardiography machine" (alternately "electrocardiogram"), has a long and distinctive history that first begin in the late 1700s with the introduction of a device called the "galvanometer." This device sensed electrical current but was not able to measure it. A few years later, a modification added a dual position switch that allowed electrical current measurement. The device's name was then changed to the "rheotome," or "flowslicer." Further modifications introduced interval variances - and resulted in the first recorded EKG readings, which were taken by placing electrodes directly on frog hearts.
In 1914, an American joined in the rounds of revision and expansion of the now collective vision for the EKG. A professor by the name of Horatio Williams designed the first American made EKG machine, and a gentleman named Charles Hindle manufactured it. This EKG machine was so accurate that it was able to pick up severe electrical disturbances to the heart such as acute anterior infarctions - so much so that medical knowledge had to work to keep up with its revelations. It was also during this time that the size and weight of what was still intermittently called the "string galvanometer" and the "EKG," was greatly reduced - from over 600 pounds to less than 30 pounds. Modification of the electrodes was soon to follow, with a size-reduced strap on electrode that was later replaced by a silver German-made direct-contact plate electrode. A suction electrode followed, which was the precursor to the suction cup electrode used today in 12-lead EKG equipment. The last modifications were to the vacuum tubes, and the direct writing instruments that are in today's EKG machines. The EKG machine has had many transformations through the years.