1903

EKG/ECG

William Einthoven (1860–1927)

Imagine how useful it would be if engineers could develop an inexpensive, reliable device to monitor the heart. It would let doctors see how a patient’s heart is performing simply by attaching a few electrodes to the patient’s skin. It is a completely non-invasive procedure that helps a doctor monitor normal heart function as well as a number of abnormalities. The ECG machine, also known as an EKG machine, is the diagnostic device that makes this dream a reality.

The first reliable EKG machine was invented by William Einthoven, a doctor working in the Netherlands, in 1903. Because of the heart’s very low signal strength, it takes a great deal of sensitivity to sense and record it. The system he invented did not use electrodes—instead patients placed their limbs in buckets of salt water to get a good connection. An extremely thin glass fiber coated in silver and placed in a strong magnetic field would move in response to the heart’s faint signals. Why this strange approach? Because electrical engineers had not yet created reliable, flexible amplifier circuits.

By projecting an image of the string’s vibrations on the screen, the EKG could be seen and interpreted. Einthoven then developed a standard naming scheme to identify the parts of the signal.

The development of the machine and the interpretation of the signals was such an important advancement that the doctor won the Nobel Prize for his work.

But this original machine weighed more than the patient and required several people to make it function. This is where engineers come in—after the scientific groundwork has been laid, they find ways to shrink the machine, better capture and display the signals, make things more reliable, and eliminate the buckets. And they succeeded spectacularly so that today an EKG machine is inexpensive and ubiquitous.

And in today’s world they have taken things a step further. The computers found in portable defibrillator machines can now read EKGs, decide if a patient is experiencing a heart attack, and administer a life-saving shock, all completely automatically. This laid the groundwork for later artificial medical products like the artificial heart.

SEE ALSO Defibrillator (1899), Radio Station (1920), Heart-Lung Machine (1926), Artificial Heart (1982).

The modern EKG is considerably more efficient than Einthoven’s original design.