by Dr. Iain Corness
Mata Hari, frogs, dogs, horses, toy trains and EKGs (ECGs)
Everyone is familiar these days with
the electrocardiogram, known by the acronym ECG or EKG (US style, which
comes from the German spelling). This is an invaluable medical test to show
the electrical conductivity of the heart, which in turn can give the doctor
an idea of the health of the heart muscle itself. Many think of this as one
of the newer developments in medical science, but it is not, having a
history dating back to the mid 1600s.
In 1664, Jan Swammerdam, a Dutchman, disproved Descartes’ previous
mechanical theory of animal motion by removing the heart of a living frog
and showing that it was still able to swim. On removing the brain all
movement stopped. (This reminded me of the professor who proved that fleas
heard through their legs. When he told intact fleas to jump they did - but
after he removed the legs they no longer moved, proving they must have
previously heard through their legs.)
Almost 200 years later, in 1856, researchers Kolliker and Muller
accidentally discovered the electrical activity of the heart when a frog
sciatic nerve and leg muscle preparation fell onto an isolated frog heart
and both muscles contracted synchronously.
The investigation into the electrical stimulation of muscles continued, with
the main stumbling block being the difficulty in measuring such small
voltages. However, in 1887, Augustus Waller, working in St Mary’s Medical
School, London, published the first human electrocardiogram, having recorded
the electrical activity of the heart of a Thomas Goswell, a technician in
the laboratory. This required not only wires, but the subject sitting with
his hands in glass jars of salt solution. Waller’s electrocardiograph
machine consisted of an electrometer fixed to a projector. The trace from
the heartbeat was enlarged by projecting it on to a photographic plate which
in turn was fixed to a toy train, to produce a graphical, moving record!
Unfortunately Waller did not see the clinical application of his EKG.
Two years later, in 1889, Dutch physiologist Willem Einthoven saw Waller
demonstrate his technique at the First International Congress of
Physiologists in Bale. Waller often demonstrated by using his dog “Jimmy”
patiently standing with his paws in glass jars of saline, and began to
develop the technique further.
What Einthoven, who was working in Leiden, did was to throw away the toy
train and use a different and much more sensitive string galvanometer that
he had invented himself in 1901. The different wave formations could be more
easily identified, and it was Einthoven who assigned the letters P, Q, R, S
and T to the various deflections, and described the electrocardiographic
features of a number of cardiovascular disorders, such as atrial
In 1909, Thomas Lewis of University College Hospital, London bought an
Einthoven string galvanometer and published a paper in the BMJ detailing his
careful clinical and electrocardiographic observations of atrial
fibrillation. Lewis identified a fibrillating horse using the string
galvanometer’s electrocardiogram recording, and then followed the horse to
the slaughterhouse where he could visually confirm the fibrillating atrium.
By 1924, the EKG, in a form close to that we know today was developed by
Einthoven, who that year was awarded the Nobel Prize in Medicine for his
Since then, the EKG has become even more sophisticated, and the equipment
much smaller in size. However, it was not until 1963 that we began to carry
out EKGs while making the heart work. This exercise ECG concept was promoted
by Robert Bruce and colleagues to describe their multistage treadmill
exercise test later known as the Bruce Protocol. “You would never buy a used
car without taking it out for a drive and seeing how the engine performed
while it was running, and the same is true for evaluating the function of
the heart,” he is rumored to have said.
So where does the famous spy Mata Hari come in? Well, somewhat tenuous I
know, but Mata (1876-1917) lived in Leiden as a young girl when Einthoven
(1860-1927) was doing his experiments there. Who knows, she might have
electrically stimulated young Willem as well as her other later exploits
which led her to the firing squad!