June 16, 2025 • 37 mins
The first electrocardiograph was invented in 1895. That device looked a lot different from today’s machines, and there are some other contenders for the title of “first.”
Research:
- AlGhatrif, Majd, and Joseph Lindsay. “A brief review: history to understand fundamentals of electrocardiography.” Journal of community hospital internal medicine perspectives vol. 2,1 10.3402/jchimp.v2i1.14383. 30 Apr. 2012, doi:10.3402/jchimp.v2i1.14383
- Baldassarre, Antonio et al. “The Role of Electrocardiography in Occupational Medicine, from Einthoven's Invention to the Digital Era of Wearable Devices.” International journal of environmental research and public health vol. 17,14 4975. 10 Jul. 2020, doi:10.3390/ijerph17144975
- Browne, Sir Thomas. “Chap. IV: Of Bodies Electrical.” From Pseudodoxia Epidemica. 1672. https://penelope.uchicago.edu/pseudodoxia/pseudo24.html
- Case Western Reserve. “Cambridge Electrocardiograph, 1920.” https://artsci.case.edu/dittrick/online-exhibits/explore-the-artifacts/cambridge-electrocardiograph-1920/
- Fisch, Charles. “Centennial of the string galvanometer and the electrocardiogram.” Journal of the American College of Cardiology. Volume 36, Issue 6, 15 November 2000. https://www.sciencedirect.com/science/article/pii/S0735109700009761
- Friedman, Paul A. “The Electrocardiogram at 100 Years: History and Future.” Circulation. Volume 149, Number 6. https://doi.org/10.1161/CIRCULATIONAHA.123.065489.
- Fye, W. Bruce. “A History of the Origin, Evolution and Impact of Electrocardiography.” The American Journal of Cardiology. Vol. 73, No. 13. 5/15/1994.
- Goodrich, Joanna. “Forget Electrodes, the First EKG Machine Used Buckets of Saline Solution and Telephone Wire.” IEEE Spectrum. 1/5/2021. https://spectrum.ieee.org/forget-electrodes-the-first-ekg-machine-used-buckets-of-saline-solution-and-telephone-wire
- Howell, Joel D. “Early Perceptions of the Electrocardiogram: From Arrythmia to Infarction.” Bulletin of the History of Medicine, SPRING 1984, Vol. 58, No. 1. Via JSTOR. https://www.jstor.org/stable/44441681
- Jenkens, Dean and Dr Stephen Gerred. “A (not so) brief history of electrocardiography.” ECG Library. 2009. https://ecglibrary.com/ecghist.html
- Macfarlane PW, Kennedy J. Automated ECG Interpretation—A Brief History from High Expectations to Deepest Networks. Hearts. 2021; 2(4):433-448. https://doi.org/10.3390/hearts2040034
- Rautaharju, Pentti M. “Eyewitness to history: Landmarks in the development of computerized electrocardiography.” Journal of Electrocardiology 49 (2016) 1 – 6.
- Rivera-Ruiz, Moises et al. “Einthoven's string galvanometer: the first electrocardiograph.” Texas Heart Institute journal vol. 35,2 (2008): 174-8.
- Salam, Amar M. “The Invention of Electrocardiography Machine.” HeartViews. 2019 Nov 14;20(4):181–183. doi: 10.4103/HEARTVIEWS.HEARTVIEWS_102_19.
- Vincent, Rony. “From a laboratory to the wearables: a review on history and evolution of electrocardiogram.” Iberoamerican Journal of Medicine, vol. 4, núm. 4, pp. 248-255, 2022. https://www.redalyc.org/journal/6920/692072548011/html/
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:01):
Welcome to Stuff You Missed in History Class, a production
of iHeartRadio. Hello, and welcome to the podcast. I'm trace
E V. Wilson, and I'm Holly Frye.
Speaker 2 (00:16):
I went to the doctor the other day. I think
that's where I picked up the cold that I feel
like is still present in my voice a little bit.
Speaker 1 (00:27):
Probably that's for sick people off and arm.
Speaker 2 (00:29):
No. I know I had a mask on the whole time,
but you know, stuff happens while I was there. The
doctor wanted to get an EKG, also called an ECG
or electro cardiogram. People use those EKG and ECG abbreviations
pretty much interchangeably. EKG is just the same word, but
(00:51):
in German. While I was waiting for somebody to come
back with the machine to do this test, I thought,
what was this inventedrobably like the twenties or the thirties,
And while waiting I looked it up on my phone
and the answer was eighteen ninety five. Of course, that
eighteen ninety five device looked a lot different from today's
electro cardiographs, which is what the machine is called. And
(01:15):
there are some other years on either side of eighteen
ninety five, that you could also say was the first regardless,
so that was earlier than I was expecting. So sitting
there at the doctor's office, I dropped what I was
working on for this show to do an electro cardiogram
episode instead as a confession. I was also working on
(01:36):
something that had turned out to be really unwieldy, and
while I was in the waiting room, I had been
sort of thinking through how in the world I was
going to get this unwieldy thing done in time to
record it. The unwieldy thing is still coming, it's just
coming later. Also, my ECG was normal in case people
are wondering, Like most of our episodes on medical developments,
(01:58):
this does include some animal experimentation. Also, if you're a
cardiologist or otherwise if you work with a lot of ECGs,
I'll just go ahead and apologize. We're not going to
talk in a lot of detail about what the actual
readout means. I don't feel remotely qualified to get into that,
and I also don't think are either muddling through it
(02:21):
or just reading somebody else's definition word for word would
actually add to the history of this in a way
that would sort of add to it. For like typical
non cardiologist, non physician type people. So the heart is
a muscle and its beats are controlled by electrical activity
(02:42):
generated in the sinus node also called the cinoaitrial node
that's a part of the heart. An electric cardiogram is
a non invasive test that measures this electrical activity using
electrodes placed on the skin, which are connected to an
electric cardiograph or ECG machine with leadwire. The machine translates
those electrical signals into a graphical representation of a wave
(03:05):
and that is immediately available to be read and interpreted.
With today's technology.
Speaker 1 (03:10):
This is typically a fast, painless test, although people who
are sensitive to adhesives or to the material the electrodes
are made from can experience some irritation. That happened to
me the first time I ever had one, yes, say
something years ago, but not with this one most recently.
This technology grew from both the study of electricity and
(03:33):
the study of anatomy and physiology, and then all that,
of course, started way before the end of the nineteenth
century when the first ECGs were invented. People have been
observing phenomena like static electricity and lightning since before the
start of recorded history, and While different societies have had
taboos around things like dissections and autopsies, people have also
(03:56):
been doing them and examining hearts and other muscles for
thousands of years. The word electricity was first used in
writing by English polymath and member of Parliament Sir Thomas
Brown in sixteen forty six in his Pseudodoxia Epidemica, or
Enquiries into Very Many Received Tenets and Commonly Presumed Truths.
(04:19):
This is a book that he wrote to try to
correct an assortment of superstitions and commonly held misinformation. It's
actually arranged into seven books, and as an example, the
third book is devoted to dispelling misinformation about animals, including
the idea that elephants don't have joints, that beavers escape
hunters by biting off their testicles, although who could blame them,
(04:42):
and that the ostrich digestith iron. Brown's descriptions of electricity
are focused on static electricity, including the ability of materials
like amber and jet to attract lightweight objects after being rubbed.
Similar words like electric and electric were coined in the
seventeenth century as well.
Speaker 2 (05:04):
I was extremely delighted by just the table of contents
at this book. In the sixteen sixties, Dutch naturalist Yon
Swammerdam carried out experiments on frogs and other animals. This
included using his scalpel or another instrument to stimulate nerve
tissue during dissections, and that would cause the corresponding muscles
(05:27):
to twitch. He believed that these muscular contractions were caused
by the flow of animal spirits or nervous fluid. There's
some debate about whether these experiments involved electricity. Some of
his instruments were made of multiple different metals, and they
had voltage differences that could have produced a small current
(05:49):
if that's the case, though he definitely was not aware
that that was what was happening.
Speaker 1 (05:55):
About one hundred years later, researchers were studying animals like
electric rays also called common torpedoes, as well as electric eels.
One was American scientist and spy Edward Bancroft, who described
torpedoes and their ability to shock people in his book
An Essay on the Natural History of Guiana. His description
(06:16):
didn't really line up with how people understood electrical charges.
At this point, it was known that metal could conduct electricity,
but that glass and sealing wax couldn't, and the idea
of electricity coming from a living thing just seemed bizarre.
Earlier descriptions of these animals had concluded that the jolts
they produced were physical, not electrical, but Bancroft did some
(06:38):
experiments showing that the shock from a torpedo was similar
to the electrical charge that could be stored in a
Leiden jar.
Speaker 2 (06:46):
In seventeen seventy two, British scientist John Walsh worked off
of Bancroft's ideas to experiment with electric rays and found
that it was possible to direct the shocks these rays
produced through a circuit of four people. He wrote letters
about this to Benjamin Franklin, and he was awarded the
(07:07):
Royal Society's Coply Medal for his paper on the torpedo
in seventeen seventy three. Then, in seventeen seventy five, Danish
physician and veterinarian Peter Christian Ablegard used electrical shocks to
quote render lifeless a bird and then to revive it.
Italian researcher Luigi Galvani experimented with frogs, and on September twentieth,
(07:30):
seventeen eighty six, he wrote, quote, I had dissected and
prepared a frog in the usual way, and while I
was attending to something else, I laid it on a
table on which stood an electrical machine, at some distance
from its conductor and separated from it by a considerable space. Now,
when one of the persons present touched accidentally and lightly
(07:53):
the inner cural nerves of the frog with the point
of a scalpel, all the muscles of the legs seemed
to contract again an again, as if they were affected
by powerful cramps. Other eighteenth century researchers experimented with using
electricity to revive the apparently dead, including English surgeon Charles
Kite and Italian scientist Alessandro Volta. It's possible that these
(08:17):
experiments were one of the inspirations for Mary Shelley's Frankenstein
or the modern Prometheus.
Speaker 1 (08:24):
In the early nineteenth century, Johann Schwager of Nuremberg developed
the first galvanometer that was an instrument to measure electrical current,
which was later named in honor of Luigi Galvani. Around
the same time, Danish physicist Hans Christian Ersted noted that
it was possible for changes in electrical current to deflect
(08:44):
a compass needle showing a connection between electricity and magnetism.
By the eighteen thirties and forties, researchers were using galvanometers
to study electrical activity in animals, not just ones that
could produce an obvious chart like electric raisin eels. This
included Italian physicist Leopoldo Nobili. In eighteen thirty four, he
(09:08):
developed an instrument called an astatic galvanometer to detect very
small electric currents, and he used it to detect a
current between a frog's limbs and spinal cord. In eighteen
forty two, Carlo Matiucci used Nobili's invention to detect electrical
currents in the hearts of pigeons.
Speaker 2 (09:27):
Within a decade, researchers had started to realize a connection
between the electrical activity of the heart and irregular heartbeats,
specifically ventricular fibrillation. Maritz Haffe described this in eighteen fifty
following experiments in the lab of his teacher Karl Ludwig,
he was able to induce ventricular fibrillation in dogs by
(09:50):
exposing their hearts to electrical currents. A few years later,
in eighteen fifty six, Albert von Kolliger and Heinrich Mueller
detected electionlectrical activity in frog hearts in a lab in Germany,
discovering that the heart generated electricity and that there was
a rhythm to it that was associated with each beat.
Speaker 1 (10:12):
Much of this animal research involved dissections or vivisections, and
scientists were detecting electrical signals from exposed skeletal muscles and hearts.
But by the late nineteenth century people started figuring out
ways to record the heart's electrical activity from outside the body.
We'll talk more about that after a sponsor break.
Speaker 2 (10:42):
In eighteen sixty nine, Scottish electrical engineer Alexander Muirhead was
working at Saint Bartholomew's Hospital in London and he found
a way to record the electrical rhythm of a patient's
beating heart. He attached an electrode to the patient's wrist
and the case connected that to a siphon recorder. This
(11:03):
recorder was developed by William Thompson as a receiver for
the extremely weak electrical signals that had traveled along underwater
telegraph cables. That used a glass tube with an increas
of war at one end, which swayed back and forth
in response to positive and negative electrical signals. This created
(11:24):
a continuous wavering line on a recording paper. For telegraph cables,
that wavering line represented the dots and dashes of Morse code,
but in muir head set up, it represented the electrical
rhythm of the heart. This was most likely the first
ever recording of electrical activity in the heart of a
(11:46):
human patient, but Muirhead did not publicize this work.
Speaker 1 (11:51):
The next major step in the development of the electric
cardiogram was the work of British physiologist Augustus Desiree Waller
at Saint Mary's Hospital, London in eighteen eighty seven. He
used a capillary electrometer developed by Gabriel Lippmann to record
electrical activity from patient's hearts. This electrometer was made out
(12:12):
of a glass tube filled with mercury. One end of
the tube was formed into a tiny capillary that could
be submerged in diluted sulfuric acid. There was an electrical
potential difference between the mercury and the sulfuric acid, so
when this setup was connected to the patient's body through
electrodes and leads, the curved surface of the mercury in
(12:37):
the tube or the meniscus would shift in response to
the current from the patient's heart. These shifts were tiny,
so they were projected onto photosensitive paper using a projecting microscope.
British physiologist John Burdon Sanderson and Frederick Page had used
a similar device to record a two phase current in
(13:00):
frog heartbeats in eighteen seventy eight. Waller called this a cardiograph,
and he did a number of experiments with it, including
working with different numbers of leads, sometimes a single lead,
sometimes two, and eventually five. Those five electrodes were on
all four of the patient's limbs and one in their mouth.
(13:21):
He used electrodes strapped to the surface of the patient's body,
as well as jars of saline solution that acted as
electrodes for the hands and feet. He also did demonstrations
of this concept with his dog, Jimmy, who would stand
with two of his feet in jars of saline. Jimmy
was reportedly a very patient dog.
Speaker 2 (13:42):
While Waller was able to record electrical signals from the
heart with the capillary electrometer, he didn't really think this
was going to be useful in clinical practice. He eventually
came to see more value in it, but earlier on
he's quoted as saying he didn't imagine that it would
thee extensive use in hospitals quote that can be at
(14:04):
most of rare and occasional use to afford a record
of some rare anomaly of cardiac action.
Speaker 1 (14:12):
One of the people who saw one of Waller's demonstrations
with Jimmy was Dutch physiologist VILLEM. Eintoven. He had been
born in Semarang, Java in eighteen sixty and he had
Jewish ancestry. Ancestors on his father's side had fled to
the Netherlands during the Spanish Inquisition. His father and his
grandfather were both doctors, and he earned both an MD
(14:35):
and a PhD from the University of Utrecht. Ethoven saw
Waller's demonstration at the International Congress of Physiology in London
in eighteen eighty seven. After seeing this demonstration, Aintoven started
working on his own device, describing it as an electro
cardiogram at the eighteen ninety three Dutch Medical Meeting. Although
(14:58):
Eintoven is usually credited with coining this term, he actually
gave the credit to Waller. Intoven started out with a
five lead setup similar to Waller's, but ultimately dropped the
two leads that he thought provided the lowest yield for
the signal. Those two leads were the one in the
mouth and the right leg. That left three leads for
(15:20):
both of the patient's hands and their left leg. All
the electrodes for the setup were buckets of saline. Inoven
studied the curves produced by this device, noticing that there
was a pattern of five deflections for each heartbeat. He
labeled these deflections ABCD, and E. He worked with mathematician
(15:42):
Heindrich Lorentz to create a formula that would account for
inertia and friction within the device. The resulting pattern looked
like what we see in an EKG today. Every person's
heartbeat is their own, but in a healthy heart that's
beating normally, the basic pattern is the same.
Speaker 2 (16:01):
Eintoven labeled those five corrected deflections as PQRS, and T.
He probably chose p AT as the starting point because
of a tradition dating back to Renee Descartes of using
letters from the second half of the alphabet. The letters
N and O were already widely being used for other purposes.
(16:21):
Aintoven published a paper detailing all this in eighteen ninety
five called Form of the Human electro cardiogram.
Speaker 1 (16:29):
Then Eintoven started working on developing a device with a
more sensitive galvanometer. He did this with a string galvanometer
made from a thread of quartz coated in silver. This
thread was suspended between the poles of an electromagnet, and
it shifted within the electromagnetic field in response to the
electrical signals from the heart. While this galvanometer was more sensitive,
(16:53):
its movements were still teeny tiny, so they had to
be magnified and projected onto a running sheet of photographic film.
He presented this device for the first time in nineteen
oh one.
Speaker 2 (17:05):
This was pretty similar to a device that had been
created by French engineer and aviator Clement Adair for receiving
underwater transmissions through wires. It seems like these two men
each came up with their devices independently of one another,
but Intoven later did acknowledge Adair's similar work.
Speaker 1 (17:25):
Although Eintoven's string galvanometer was more sensitive and precise than
the capillary device had been, that did not mean that
it was small or easy to use. It weighed more
than six hundred sixty pounds or three hundred kilograms, and
it took up two rooms It required a large electromagnet
which had to be continually cooled with flowing water to
(17:47):
keep it from overheating, and it required five people to operate.
So by nineteen oh three Etoven was working on making
a commercial version of this device which could actually be
used and clinical medicine. This was not really that would
be a long process and in the meantime it just
(18:08):
it wasn't possible to move his device from the laboratory,
where it took up two rooms, to a hospital where
it could be used with patients more easily. His colleague
Johannes Bosha made a suggestion, and that was to connect
to the electro cardiogram at the lab to the academic
hospital in Leiden, roughly a mile or fifteen hundred meters away.
(18:29):
They did this with a telephone line. Patients in the
hospital placed both of their arms and one of their
legs in buckets of saline, with those buckets acting as electrodes,
and they were connected to a telephone line that carried
their electrical signal to the galvanometer in the lab.
Speaker 2 (18:48):
Then they could read the electro cardiogram in the lab
almost a mile away. On March twenty second of nineteen
oh five, the first telecardiogram was transmitted from the hospital.
Speaker 1 (18:58):
Einthoven published a paper called Leutelecardiogram in nineteen oh six.
This work detailed a number of arrhythmias and other issues
that could be detected by examining the results of an
electro cardiogram, including mitral insufficiency, left ventricular hypertrophy, premature ventricular contractions,
and atrial flutter. By this point, Cambridge Scientific Instrument Company
(19:23):
of London had developed a commercial version of the Eintoven
electric cardiograph, and it had sold three of them. All
three were for use in laboratory research, though not for
clinical work in human medical patients. The first purchase of
one of these machines for clinical work was in nineteen
oh eight. We'll talk about how electric cardiographs and electrocardiograms
(19:48):
developed from here. After another sponsor break, in.
Speaker 2 (20:00):
Nineteen eleven, Cambridge Instrument Company released a table model of
William Eintoven's electro cardiograph. This one was still a lot
bigger than most of today's machines that you might see
in a doctor's office. It still required patients to sit
with both of their hands and one of their feet
in buckets of saline, so it was still relatively cumbersome,
(20:23):
but it was way more compact than that two room,
six hundred pound original version, and doctors had also figured
out all kinds of conditions and abnormalities that could be
detected and diagnosed through the patterns in an electro cardiogram.
Doctors and hospitals were a little slower to adopt this
technology than they had been with the first X ray machines,
(20:44):
but by the time this table model was introduced, electric
cardiograms were starting to be regarded as critical to cardiac care.
We talked about the development of X rays in our
episode on mimography on January thirty first, twenty twenty four,
and the modern blood pressure cuff in our episode on
hypertension on August first, twenty twenty two. X ray machines,
(21:06):
blood pressure cuffs, and electric cardiograms were all developed and
refined around the turn of the twentieth century, and together
they were critical to the development of cardiology as a
specific medical field. I've also realized these are three episodes
from our catalog, including this one, all inspired by my
own medical experiences. In nineteen twelve, Welsh cardiologist Thomas Lewis
(21:31):
delivered a lecture at University College Hospital titled on the
evidences of Auricular Fibrillation Treated Historically. He described various arrhythmias
as clearly visible and recognizable in the waves of an
electro cardiogram, including fibrillations that is, a heart that's fluttering
(21:51):
or twitching in an unsynchronized way rather than beating in
a regular pattern. He also discussed the examination of a
horse that showed evidence of atrial fibrillation due to heart disease,
not something that had been induced in the horse through experimentation,
which had been the case in some of the other
animal research. He found that the waves from the horse's
(22:15):
heart were basically the same as that of a human's,
and he confirmed that the heart really was in atrial
fibrillation by actually looking at it during a surgical examination.
Lewis was a regular correspondent with Einthoven, and he was
also building on the work of Scottish cardiologist James Mackenzie,
who developed a polygraph machine that traced patient's pulses at
(22:37):
the wrist and neck, which could also show evidence of arrhythmias.
This was simpler than the polygraph machines that supposedly work
as light detectors. Today those also measure other physiological responses.
Like Augustus Waller, who we mentioned earlier, Lewis didn't really
think electric cardiograms could be very useful in clinical medicine,
(22:59):
but this largely because they were still pretty cumbersome. ECGs
could only capture a few seconds of activity, and since
the results were projected onto photosensitive paper, they had to
be developed before they could be interpreted. But Mackenzie's polygraph
used ink on a running roll of paper, its pulse
tracings were visible immediately. Lewis also noted that at this point,
(23:23):
treatment for suspected cardiac issues was the same regardless of
whether a person had been given an electric cardiogram or not.
As the technology improved, though, Lewis updated his opinion, saying, quote,
the time is at hand, if not already come, when
an examination of the heart is incomplete, if this new
method is neglected. Eindoven was still making new discoveries, and
(23:48):
in nineteen twelve he described his system of three leads
as an equilateral triangle that the concept known as Eindhoven's
triangle today. His written work on this it was probably
the first use in writing of the abbreviation EKG.
Speaker 1 (24:05):
In nineteen eighteen, physician and professor James Herrick of Chicago
demonstrated that it was possible to use an ECG to
diagnose a myocardial infarction commonly called a heart attack. American
cardiologist Harold Party published work on diagnosing coronary artery obstructions
through electric cardiograms in nineteen twenty. In nineteen twenty four,
(24:29):
Villain Einsoven was awarded the Nobel Prize in Physiology or
Medicine for his discovery of the mechanism of the electro cardiogram.
The presentation speech made it clear that this award was
not only about Eindhoven's development of the electro cardiograph device.
It was also about his interpretations of the electro cardiograms,
(24:52):
what pqrs and T each corresponded to in a beating heart,
and how to identify so many different disorders and diseases
of the heart through the analysis and interpretation of that
one wave. Other researchers had offered other methods of interpretation,
but in the words of the award speech quote, Eintoven's
(25:14):
concept is the only one which has proved to be tenable.
The Nobel prize came with a monetary award that Eintoven
wanted to split with his assistant, who had worked with
him during the early years of his work and the
development of this device. His name was von Deiverd. Vondiverd
had died, though, and Eintoven instead divided the forty thousand
(25:35):
dollars prize money with Vondiverd's two sisters, who had been
living in poverty. Three years later, on September twenty ninth,
nineteen twenty seven, Billem Eintoven died of cancer. Also in
nineteen twenty seven, Japanese physician Tarro Takem developed the first
portable ECG machine. Two years later, the Sanborn Company of Waltham,
(25:58):
Massachusetts released the Sanborn Visocardiac, which was a portable version
that could print the results immediately on a roll of
paper that weighed about twenty six pounds or twelve kilograms,
and it was powered by a car battery. In nineteen
thirty four, physiologist Frank N. Wilson started working on standardizing
the use and placement of electrodes and leads. He realized
(26:22):
that the typical three lead system left some areas of
the heart that weren't fully represented in the ECG wave.
He added another lead, described as an exploring lead, which
could be used along with the three standard leads to
read the electrical activity of specific parts of the heart.
I couldn't pinpoint exactly when these machines moved away from
(26:45):
having people put their hands and feet in buckets of saline,
but these exploratory leads typically went somewhere on the chest,
so they would have used surface electrodes at some point,
though ECG's did start to use only electrodes that were
placed on the body. Today, these are usually little adhesive discs.
By the nineteen thirties, it had become clear that ECGs
(27:08):
could be used to help diagnose whether a patient's chest
pain had a cardiac or non cardiac cause. In nineteen
thirty five, Boston physicians Sylvester McGinn and Paul White published
work describing changes in ECG readings that were apparent in
patients who were experiencing an acute pulmonary embolism. These changes
(27:29):
are now known as the m again White pattern.
Speaker 2 (27:33):
In nineteen thirty eight, the American Heart Association and the
Cardiac Society of Great Britain tried to standardize the placements
of that exploratory lead that had been introduced about four
years before. They recommended six specific sites, now known as
V one to V six. These are called the pre
cordial leads or the chest leads today. In nineteen forty two,
(27:57):
New York cardiologist Emmanuel Goldberger also worked with the number
and types of leads, and that started moving toward the
twelve lead electro cardiogram that is most commonly used today.
There are also other numbers of leads that are used
for particular purposes, but like the most common standard in
a medical setting today is twelve leads. In nineteen forty eight,
(28:22):
Swedish engineer Runa Emquist, who had also trained as a physician,
developed the first inkjet ECG printer. He would also go
on to be a big part of the development of
the first implantable pacemaker. By the nineteen fifties, researchers were
working on finding ways to automate ECG readings. The development
(28:43):
of automated readings also made other life saving developments possible,
like automated external defibrillators, which automatically diagnose arrhythmias and then
deliver shocks only when they are warranted. Today, a lot
of ECGs are automatically analyzed before being reviewed by cardiologists, internists,
(29:03):
primary care doctors, or other medical professionals. The automation of
ECG readings was possible thanks to the advent of computers
and microprocessors, which have continued to have a huge role
in making electric cardiograph machines much smaller and easier to use.
In nineteen fifty seven, American biophysicist Norman Jeffrey's Halter developed
(29:25):
the dynamic ECG, often known as the Halter ECG or
a Halter monitor, which is a portable device that can
continually monitor a patient's heart for twenty four hours or more. Today,
Holter monitors are wearable devices, weighing a couple of pounds
at most, but they initially weighed about eighty three pounds
or thirty eight kilograms and had to be worn like
(29:47):
a huge heavy backpack. Magneto cardiograms were introduced in nineteen
sixty three, which could record heart rhythms without the patient
needing to have electrodes on their body. Very expensive, though,
so they never really took off. That same year, American
cardiologist Robert A. Bruce developed a protocol to record a
(30:08):
person's cardiac signals while they did progressively more intense exercise
on a treadmill that today is known as the Bruce protocol.
Speaker 1 (30:17):
And of course, ECGs have continued to evolve with changes
in technology. By nineteen ninety nine, there were twelve lead
ECGs that could send their results directly to handheld computers. Today,
there are a range of consumer ECG devices that are tiny,
everything from the ECG function on an Apple Watch to
(30:37):
a device the size of a credit card that communicates
with an app, to home devices that can record an
ECG and also measure a person's blood pressure. There are
pros and cons to all of these, a big one
being that while a twelve lead ECG is considered standard
in medical settings today, most of these home use models
only use one or two leads. The device or app
(31:01):
also typically interprets the ECG automatically and displays the results,
and that can lead to various false negatives or false positives.
Speaker 2 (31:10):
If you're me and you have an Apple Watch, it
could also be that the Apple to Watch just incessantly
starts over telling you like cycling through all the things
that thinks you're doing wrong, rather than ever fully recording
the ECG I've done a lot of troubleshooting on that
that has not been successful. I also have some listener
mail that is also somewhat medical related.
Speaker 1 (31:33):
It is from Edith.
Speaker 2 (31:35):
Edith says, Hi, Holly and Tracy. I've been wanting to
write forever, but never had anything I thought worthy of
writing about until now. So this will probably be a
combination of things I didn't think worthy but still want
to say, and a story. First of all, I'm writing
this while in the airport on a way from Boston
to Atlanta, which I find kind of funny and coincidental.
On my drive to the airport, I was listening to
(31:55):
the behind the scenes following the tetanus episode. More on
this later. That's the story, first of all, as a
fifty year old former theater kid who loves to sew,
has far too much clothing and too many pairs of shoes,
and doesn't like my body to be unexpectedly exposed to unpleasantness.
Slippers for the wind, Holly, I see you now. I
(32:18):
have to thank you for your unintentional PSA. I just
turned fifty in April and really had not thought about vaccinations.
I mean, I still think and maybe act like I'm thirty.
But when you all mentioned that we, yes, us are
of an age where we probably only got one measle shot,
I was like, huh, I did not know that, So
now I know to ask about that at my next physical.
Speaker 1 (32:37):
Thanks. Okay, okay, finally the story and the behind the scenes.
You both told stories about extra tetanus shots, so I
wanted to tell you about mine. I was in high
school in Cambridge, Massachusetts, and I did crew. Of course,
we rowed on the Charles River. One day when we
were putting the boats away, I somehow got caught in
a bad spot going around the corner and ended up
(32:57):
in the water. Now I know that the.
Speaker 2 (33:00):
Charles isn't thought of as very clean now, but back then,
well the things you would see floating there were bad.
So I fell in and that's how I ended up
getting a tetanus booster. I will pause and say that
the title of this email is love that dirty Water, Boston,
You're My Home, which is of course a song lyric reference,
referencing also the very dirtiness of both the.
Speaker 1 (33:23):
Charles and Boston Harbor at that time.
Speaker 2 (33:25):
Anyway, the email continues, anyway, I don't have any pets,
so I'm attaching a variety of collected animal pictures, including
a pig video, some horses from our neighbor's farm, an
old picture of my daughter and my brother in law's
old dog, and a current picture of my daughter on
a horse wor comparison. Thank you for all you do
as a former Medford resident. For the statement at the
(33:45):
beginning of the latest Unearthed episode, love you guys. I
tried but failed to keep it short, Edith, Edith, I
love this email. Regarding vaccinations. We had talked in I
think behind the scenes on the show about how I
was turning fifty. I knew that I meant that meant
that I was going to need to go and get
some vaccines that are recommended at the age of fifty.
I did do that those vaccines were shingles in newmacocle pneumonia.
(34:12):
I did both of those at the same time, because
somehow I thought that the people saying that sometimes the
shingles vaccine can make you feel a little unwell, I
just thought that might not apply to me, because I
am not known to have ever actually had chicken box,
but it is recommended at the age of fifty. Anyway,
(34:32):
I did feel I felt unwell. Still much better than
getting shingles or pneumonia. So yeah, that's done. I will
need shot two of the shingles shot a little bit later. Also,
lots of great animal pictures. Man, I love horse pictures.
They're so beautiful. Are a horse and a fold just
(34:54):
running through a field? Oh?
Speaker 1 (34:55):
Great? Is that?
Speaker 2 (34:57):
I don't think I'll watch the big video while we
are sitting here.
Speaker 1 (35:01):
I love a little pig action. You just reminded me
of the funniest thing I've ever seen a pig do
just now, have you ever seen a pig eat spaghetti? No,
our mutual friend, who is often prone to wacky high jinks,
(35:23):
briefly had a pig. I don't remember how she came
in to possession of the pig. She only had it
a brief period of time while she was rehoming it
and trying to find somebody that actually had like acreage
that they could raise a pig on. But in the meantime,
she and her amazing mother were just trying to keep
the pig fed and happy, and her mother started regularly
(35:43):
making the pig plates of spaghetti. It was the cutest
thing I ever saw in my life. I'm imagining what
it would look like, and it does seem very cute.
We were tiny at the time. He was still a piglet,
and so he would get the spaghetti all wound around
his snout and then try to chase it around the
house trying to get the spaghett Yeah. I wish this
were like a required thing that everybody could see in
(36:04):
their life because it brings so much joy.
Speaker 2 (36:06):
Yeah, because I am a fan of Game Changer, I
am imagining this pig wearing a tiny hat while eating
the he was not, so thank you so much for
this email, Edith, the Charles River is a lot cleaner
than it used to be. As somebody who moved to
(36:28):
the Boston area from elsewhere, I have a fondness for
seeing people rowing out on the river. I don't know
how local people feel about the rowers. I'm always a
little happy when I'm usually on the tee and I
go over the bridge and I'm like, oh, people rowing
out on the river. So, if you would like to
send us a note about this or any other podcast
or a history podcast at iHeartRadio dot com, and you
(36:52):
can subscribe to our show on the iHeartRadio app and
anywhere else if you like to et your podcasts. Stuff
you Missed in History Class is a production of iHeartRadio.
For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows.
Welcome to Stuff You Missed in History Class, a production
of iHeartRadio. Hello, and welcome to the podcast. I'm trace
E V. Wilson, and I'm Holly Frye.
Speaker 2 (00:16):
I went to the doctor the other day. I think
that's where I picked up the cold that I feel
like is still present in my voice a little bit.
Speaker 1 (00:27):
Probably that's for sick people off and arm.
Speaker 2 (00:29):
No. I know I had a mask on the whole time,
but you know, stuff happens while I was there. The
doctor wanted to get an EKG, also called an ECG
or electro cardiogram. People use those EKG and ECG abbreviations
pretty much interchangeably. EKG is just the same word, but
(00:51):
in German. While I was waiting for somebody to come
back with the machine to do this test, I thought,
what was this inventedrobably like the twenties or the thirties,
And while waiting I looked it up on my phone
and the answer was eighteen ninety five. Of course, that
eighteen ninety five device looked a lot different from today's
electro cardiographs, which is what the machine is called. And
(01:15):
there are some other years on either side of eighteen
ninety five, that you could also say was the first regardless,
so that was earlier than I was expecting. So sitting
there at the doctor's office, I dropped what I was
working on for this show to do an electro cardiogram
episode instead as a confession. I was also working on
(01:36):
something that had turned out to be really unwieldy, and
while I was in the waiting room, I had been
sort of thinking through how in the world I was
going to get this unwieldy thing done in time to
record it. The unwieldy thing is still coming, it's just
coming later. Also, my ECG was normal in case people
are wondering, Like most of our episodes on medical developments,
(01:58):
this does include some animal experimentation. Also, if you're a
cardiologist or otherwise if you work with a lot of ECGs,
I'll just go ahead and apologize. We're not going to
talk in a lot of detail about what the actual
readout means. I don't feel remotely qualified to get into that,
and I also don't think are either muddling through it
(02:21):
or just reading somebody else's definition word for word would
actually add to the history of this in a way
that would sort of add to it. For like typical
non cardiologist, non physician type people. So the heart is
a muscle and its beats are controlled by electrical activity
(02:42):
generated in the sinus node also called the cinoaitrial node
that's a part of the heart. An electric cardiogram is
a non invasive test that measures this electrical activity using
electrodes placed on the skin, which are connected to an
electric cardiograph or ECG machine with leadwire. The machine translates
those electrical signals into a graphical representation of a wave
(03:05):
and that is immediately available to be read and interpreted.
With today's technology.
Speaker 1 (03:10):
This is typically a fast, painless test, although people who
are sensitive to adhesives or to the material the electrodes
are made from can experience some irritation. That happened to
me the first time I ever had one, yes, say
something years ago, but not with this one most recently.
This technology grew from both the study of electricity and
(03:33):
the study of anatomy and physiology, and then all that,
of course, started way before the end of the nineteenth
century when the first ECGs were invented. People have been
observing phenomena like static electricity and lightning since before the
start of recorded history, and While different societies have had
taboos around things like dissections and autopsies, people have also
(03:56):
been doing them and examining hearts and other muscles for
thousands of years. The word electricity was first used in
writing by English polymath and member of Parliament Sir Thomas
Brown in sixteen forty six in his Pseudodoxia Epidemica, or
Enquiries into Very Many Received Tenets and Commonly Presumed Truths.
(04:19):
This is a book that he wrote to try to
correct an assortment of superstitions and commonly held misinformation. It's
actually arranged into seven books, and as an example, the
third book is devoted to dispelling misinformation about animals, including
the idea that elephants don't have joints, that beavers escape
hunters by biting off their testicles, although who could blame them,
(04:42):
and that the ostrich digestith iron. Brown's descriptions of electricity
are focused on static electricity, including the ability of materials
like amber and jet to attract lightweight objects after being rubbed.
Similar words like electric and electric were coined in the
seventeenth century as well.
Speaker 2 (05:04):
I was extremely delighted by just the table of contents
at this book. In the sixteen sixties, Dutch naturalist Yon
Swammerdam carried out experiments on frogs and other animals. This
included using his scalpel or another instrument to stimulate nerve
tissue during dissections, and that would cause the corresponding muscles
(05:27):
to twitch. He believed that these muscular contractions were caused
by the flow of animal spirits or nervous fluid. There's
some debate about whether these experiments involved electricity. Some of
his instruments were made of multiple different metals, and they
had voltage differences that could have produced a small current
(05:49):
if that's the case, though he definitely was not aware
that that was what was happening.
Speaker 1 (05:55):
About one hundred years later, researchers were studying animals like
electric rays also called common torpedoes, as well as electric eels.
One was American scientist and spy Edward Bancroft, who described
torpedoes and their ability to shock people in his book
An Essay on the Natural History of Guiana. His description
(06:16):
didn't really line up with how people understood electrical charges.
At this point, it was known that metal could conduct electricity,
but that glass and sealing wax couldn't, and the idea
of electricity coming from a living thing just seemed bizarre.
Earlier descriptions of these animals had concluded that the jolts
they produced were physical, not electrical, but Bancroft did some
(06:38):
experiments showing that the shock from a torpedo was similar
to the electrical charge that could be stored in a
Leiden jar.
Speaker 2 (06:46):
In seventeen seventy two, British scientist John Walsh worked off
of Bancroft's ideas to experiment with electric rays and found
that it was possible to direct the shocks these rays
produced through a circuit of four people. He wrote letters
about this to Benjamin Franklin, and he was awarded the
(07:07):
Royal Society's Coply Medal for his paper on the torpedo
in seventeen seventy three. Then, in seventeen seventy five, Danish
physician and veterinarian Peter Christian Ablegard used electrical shocks to
quote render lifeless a bird and then to revive it.
Italian researcher Luigi Galvani experimented with frogs, and on September twentieth,
(07:30):
seventeen eighty six, he wrote, quote, I had dissected and
prepared a frog in the usual way, and while I
was attending to something else, I laid it on a
table on which stood an electrical machine, at some distance
from its conductor and separated from it by a considerable space. Now,
when one of the persons present touched accidentally and lightly
(07:53):
the inner cural nerves of the frog with the point
of a scalpel, all the muscles of the legs seemed
to contract again an again, as if they were affected
by powerful cramps. Other eighteenth century researchers experimented with using
electricity to revive the apparently dead, including English surgeon Charles
Kite and Italian scientist Alessandro Volta. It's possible that these
(08:17):
experiments were one of the inspirations for Mary Shelley's Frankenstein
or the modern Prometheus.
Speaker 1 (08:24):
In the early nineteenth century, Johann Schwager of Nuremberg developed
the first galvanometer that was an instrument to measure electrical current,
which was later named in honor of Luigi Galvani. Around
the same time, Danish physicist Hans Christian Ersted noted that
it was possible for changes in electrical current to deflect
(08:44):
a compass needle showing a connection between electricity and magnetism.
By the eighteen thirties and forties, researchers were using galvanometers
to study electrical activity in animals, not just ones that
could produce an obvious chart like electric raisin eels. This
included Italian physicist Leopoldo Nobili. In eighteen thirty four, he
(09:08):
developed an instrument called an astatic galvanometer to detect very
small electric currents, and he used it to detect a
current between a frog's limbs and spinal cord. In eighteen
forty two, Carlo Matiucci used Nobili's invention to detect electrical
currents in the hearts of pigeons.
Speaker 2 (09:27):
Within a decade, researchers had started to realize a connection
between the electrical activity of the heart and irregular heartbeats,
specifically ventricular fibrillation. Maritz Haffe described this in eighteen fifty
following experiments in the lab of his teacher Karl Ludwig,
he was able to induce ventricular fibrillation in dogs by
(09:50):
exposing their hearts to electrical currents. A few years later,
in eighteen fifty six, Albert von Kolliger and Heinrich Mueller
detected electionlectrical activity in frog hearts in a lab in Germany,
discovering that the heart generated electricity and that there was
a rhythm to it that was associated with each beat.
Speaker 1 (10:12):
Much of this animal research involved dissections or vivisections, and
scientists were detecting electrical signals from exposed skeletal muscles and hearts.
But by the late nineteenth century people started figuring out
ways to record the heart's electrical activity from outside the body.
We'll talk more about that after a sponsor break.
Speaker 2 (10:42):
In eighteen sixty nine, Scottish electrical engineer Alexander Muirhead was
working at Saint Bartholomew's Hospital in London and he found
a way to record the electrical rhythm of a patient's
beating heart. He attached an electrode to the patient's wrist
and the case connected that to a siphon recorder. This
(11:03):
recorder was developed by William Thompson as a receiver for
the extremely weak electrical signals that had traveled along underwater
telegraph cables. That used a glass tube with an increas
of war at one end, which swayed back and forth
in response to positive and negative electrical signals. This created
(11:24):
a continuous wavering line on a recording paper. For telegraph cables,
that wavering line represented the dots and dashes of Morse code,
but in muir head set up, it represented the electrical
rhythm of the heart. This was most likely the first
ever recording of electrical activity in the heart of a
(11:46):
human patient, but Muirhead did not publicize this work.
Speaker 1 (11:51):
The next major step in the development of the electric
cardiogram was the work of British physiologist Augustus Desiree Waller
at Saint Mary's Hospital, London in eighteen eighty seven. He
used a capillary electrometer developed by Gabriel Lippmann to record
electrical activity from patient's hearts. This electrometer was made out
(12:12):
of a glass tube filled with mercury. One end of
the tube was formed into a tiny capillary that could
be submerged in diluted sulfuric acid. There was an electrical
potential difference between the mercury and the sulfuric acid, so
when this setup was connected to the patient's body through
electrodes and leads, the curved surface of the mercury in
(12:37):
the tube or the meniscus would shift in response to
the current from the patient's heart. These shifts were tiny,
so they were projected onto photosensitive paper using a projecting microscope.
British physiologist John Burdon Sanderson and Frederick Page had used
a similar device to record a two phase current in
(13:00):
frog heartbeats in eighteen seventy eight. Waller called this a cardiograph,
and he did a number of experiments with it, including
working with different numbers of leads, sometimes a single lead,
sometimes two, and eventually five. Those five electrodes were on
all four of the patient's limbs and one in their mouth.
(13:21):
He used electrodes strapped to the surface of the patient's body,
as well as jars of saline solution that acted as
electrodes for the hands and feet. He also did demonstrations
of this concept with his dog, Jimmy, who would stand
with two of his feet in jars of saline. Jimmy
was reportedly a very patient dog.
Speaker 2 (13:42):
While Waller was able to record electrical signals from the
heart with the capillary electrometer, he didn't really think this
was going to be useful in clinical practice. He eventually
came to see more value in it, but earlier on
he's quoted as saying he didn't imagine that it would
thee extensive use in hospitals quote that can be at
(14:04):
most of rare and occasional use to afford a record
of some rare anomaly of cardiac action.
Speaker 1 (14:12):
One of the people who saw one of Waller's demonstrations
with Jimmy was Dutch physiologist VILLEM. Eintoven. He had been
born in Semarang, Java in eighteen sixty and he had
Jewish ancestry. Ancestors on his father's side had fled to
the Netherlands during the Spanish Inquisition. His father and his
grandfather were both doctors, and he earned both an MD
(14:35):
and a PhD from the University of Utrecht. Ethoven saw
Waller's demonstration at the International Congress of Physiology in London
in eighteen eighty seven. After seeing this demonstration, Aintoven started
working on his own device, describing it as an electro
cardiogram at the eighteen ninety three Dutch Medical Meeting. Although
(14:58):
Eintoven is usually credited with coining this term, he actually
gave the credit to Waller. Intoven started out with a
five lead setup similar to Waller's, but ultimately dropped the
two leads that he thought provided the lowest yield for
the signal. Those two leads were the one in the
mouth and the right leg. That left three leads for
(15:20):
both of the patient's hands and their left leg. All
the electrodes for the setup were buckets of saline. Inoven
studied the curves produced by this device, noticing that there
was a pattern of five deflections for each heartbeat. He
labeled these deflections ABCD, and E. He worked with mathematician
(15:42):
Heindrich Lorentz to create a formula that would account for
inertia and friction within the device. The resulting pattern looked
like what we see in an EKG today. Every person's
heartbeat is their own, but in a healthy heart that's
beating normally, the basic pattern is the same.
Speaker 2 (16:01):
Eintoven labeled those five corrected deflections as PQRS, and T.
He probably chose p AT as the starting point because
of a tradition dating back to Renee Descartes of using
letters from the second half of the alphabet. The letters
N and O were already widely being used for other purposes.
(16:21):
Aintoven published a paper detailing all this in eighteen ninety
five called Form of the Human electro cardiogram.
Speaker 1 (16:29):
Then Eintoven started working on developing a device with a
more sensitive galvanometer. He did this with a string galvanometer
made from a thread of quartz coated in silver. This
thread was suspended between the poles of an electromagnet, and
it shifted within the electromagnetic field in response to the
electrical signals from the heart. While this galvanometer was more sensitive,
(16:53):
its movements were still teeny tiny, so they had to
be magnified and projected onto a running sheet of photographic film.
He presented this device for the first time in nineteen
oh one.
Speaker 2 (17:05):
This was pretty similar to a device that had been
created by French engineer and aviator Clement Adair for receiving
underwater transmissions through wires. It seems like these two men
each came up with their devices independently of one another,
but Intoven later did acknowledge Adair's similar work.
Speaker 1 (17:25):
Although Eintoven's string galvanometer was more sensitive and precise than
the capillary device had been, that did not mean that
it was small or easy to use. It weighed more
than six hundred sixty pounds or three hundred kilograms, and
it took up two rooms It required a large electromagnet
which had to be continually cooled with flowing water to
(17:47):
keep it from overheating, and it required five people to operate.
So by nineteen oh three Etoven was working on making
a commercial version of this device which could actually be
used and clinical medicine. This was not really that would
be a long process and in the meantime it just
(18:08):
it wasn't possible to move his device from the laboratory,
where it took up two rooms, to a hospital where
it could be used with patients more easily. His colleague
Johannes Bosha made a suggestion, and that was to connect
to the electro cardiogram at the lab to the academic
hospital in Leiden, roughly a mile or fifteen hundred meters away.
(18:29):
They did this with a telephone line. Patients in the
hospital placed both of their arms and one of their
legs in buckets of saline, with those buckets acting as electrodes,
and they were connected to a telephone line that carried
their electrical signal to the galvanometer in the lab.
Speaker 2 (18:48):
Then they could read the electro cardiogram in the lab
almost a mile away. On March twenty second of nineteen
oh five, the first telecardiogram was transmitted from the hospital.
Speaker 1 (18:58):
Einthoven published a paper called Leutelecardiogram in nineteen oh six.
This work detailed a number of arrhythmias and other issues
that could be detected by examining the results of an
electro cardiogram, including mitral insufficiency, left ventricular hypertrophy, premature ventricular contractions,
and atrial flutter. By this point, Cambridge Scientific Instrument Company
(19:23):
of London had developed a commercial version of the Eintoven
electric cardiograph, and it had sold three of them. All
three were for use in laboratory research, though not for
clinical work in human medical patients. The first purchase of
one of these machines for clinical work was in nineteen
oh eight. We'll talk about how electric cardiographs and electrocardiograms
(19:48):
developed from here. After another sponsor break, in.
Speaker 2 (20:00):
Nineteen eleven, Cambridge Instrument Company released a table model of
William Eintoven's electro cardiograph. This one was still a lot
bigger than most of today's machines that you might see
in a doctor's office. It still required patients to sit
with both of their hands and one of their feet
in buckets of saline, so it was still relatively cumbersome,
(20:23):
but it was way more compact than that two room,
six hundred pound original version, and doctors had also figured
out all kinds of conditions and abnormalities that could be
detected and diagnosed through the patterns in an electro cardiogram.
Doctors and hospitals were a little slower to adopt this
technology than they had been with the first X ray machines,
(20:44):
but by the time this table model was introduced, electric
cardiograms were starting to be regarded as critical to cardiac care.
We talked about the development of X rays in our
episode on mimography on January thirty first, twenty twenty four,
and the modern blood pressure cuff in our episode on
hypertension on August first, twenty twenty two. X ray machines,
(21:06):
blood pressure cuffs, and electric cardiograms were all developed and
refined around the turn of the twentieth century, and together
they were critical to the development of cardiology as a
specific medical field. I've also realized these are three episodes
from our catalog, including this one, all inspired by my
own medical experiences. In nineteen twelve, Welsh cardiologist Thomas Lewis
(21:31):
delivered a lecture at University College Hospital titled on the
evidences of Auricular Fibrillation Treated Historically. He described various arrhythmias
as clearly visible and recognizable in the waves of an
electro cardiogram, including fibrillations that is, a heart that's fluttering
(21:51):
or twitching in an unsynchronized way rather than beating in
a regular pattern. He also discussed the examination of a
horse that showed evidence of atrial fibrillation due to heart disease,
not something that had been induced in the horse through experimentation,
which had been the case in some of the other
animal research. He found that the waves from the horse's
(22:15):
heart were basically the same as that of a human's,
and he confirmed that the heart really was in atrial
fibrillation by actually looking at it during a surgical examination.
Lewis was a regular correspondent with Einthoven, and he was
also building on the work of Scottish cardiologist James Mackenzie,
who developed a polygraph machine that traced patient's pulses at
(22:37):
the wrist and neck, which could also show evidence of arrhythmias.
This was simpler than the polygraph machines that supposedly work
as light detectors. Today those also measure other physiological responses.
Like Augustus Waller, who we mentioned earlier, Lewis didn't really
think electric cardiograms could be very useful in clinical medicine,
(22:59):
but this largely because they were still pretty cumbersome. ECGs
could only capture a few seconds of activity, and since
the results were projected onto photosensitive paper, they had to
be developed before they could be interpreted. But Mackenzie's polygraph
used ink on a running roll of paper, its pulse
tracings were visible immediately. Lewis also noted that at this point,
(23:23):
treatment for suspected cardiac issues was the same regardless of
whether a person had been given an electric cardiogram or not.
As the technology improved, though, Lewis updated his opinion, saying, quote,
the time is at hand, if not already come, when
an examination of the heart is incomplete, if this new
method is neglected. Eindoven was still making new discoveries, and
(23:48):
in nineteen twelve he described his system of three leads
as an equilateral triangle that the concept known as Eindhoven's
triangle today. His written work on this it was probably
the first use in writing of the abbreviation EKG.
Speaker 1 (24:05):
In nineteen eighteen, physician and professor James Herrick of Chicago
demonstrated that it was possible to use an ECG to
diagnose a myocardial infarction commonly called a heart attack. American
cardiologist Harold Party published work on diagnosing coronary artery obstructions
through electric cardiograms in nineteen twenty. In nineteen twenty four,
(24:29):
Villain Einsoven was awarded the Nobel Prize in Physiology or
Medicine for his discovery of the mechanism of the electro cardiogram.
The presentation speech made it clear that this award was
not only about Eindhoven's development of the electro cardiograph device.
It was also about his interpretations of the electro cardiograms,
(24:52):
what pqrs and T each corresponded to in a beating heart,
and how to identify so many different disorders and diseases
of the heart through the analysis and interpretation of that
one wave. Other researchers had offered other methods of interpretation,
but in the words of the award speech quote, Eintoven's
(25:14):
concept is the only one which has proved to be tenable.
The Nobel prize came with a monetary award that Eintoven
wanted to split with his assistant, who had worked with
him during the early years of his work and the
development of this device. His name was von Deiverd. Vondiverd
had died, though, and Eintoven instead divided the forty thousand
(25:35):
dollars prize money with Vondiverd's two sisters, who had been
living in poverty. Three years later, on September twenty ninth,
nineteen twenty seven, Billem Eintoven died of cancer. Also in
nineteen twenty seven, Japanese physician Tarro Takem developed the first
portable ECG machine. Two years later, the Sanborn Company of Waltham,
(25:58):
Massachusetts released the Sanborn Visocardiac, which was a portable version
that could print the results immediately on a roll of
paper that weighed about twenty six pounds or twelve kilograms,
and it was powered by a car battery. In nineteen
thirty four, physiologist Frank N. Wilson started working on standardizing
the use and placement of electrodes and leads. He realized
(26:22):
that the typical three lead system left some areas of
the heart that weren't fully represented in the ECG wave.
He added another lead, described as an exploring lead, which
could be used along with the three standard leads to
read the electrical activity of specific parts of the heart.
I couldn't pinpoint exactly when these machines moved away from
(26:45):
having people put their hands and feet in buckets of saline,
but these exploratory leads typically went somewhere on the chest,
so they would have used surface electrodes at some point,
though ECG's did start to use only electrodes that were
placed on the body. Today, these are usually little adhesive discs.
By the nineteen thirties, it had become clear that ECGs
(27:08):
could be used to help diagnose whether a patient's chest
pain had a cardiac or non cardiac cause. In nineteen
thirty five, Boston physicians Sylvester McGinn and Paul White published
work describing changes in ECG readings that were apparent in
patients who were experiencing an acute pulmonary embolism. These changes
(27:29):
are now known as the m again White pattern.
Speaker 2 (27:33):
In nineteen thirty eight, the American Heart Association and the
Cardiac Society of Great Britain tried to standardize the placements
of that exploratory lead that had been introduced about four
years before. They recommended six specific sites, now known as
V one to V six. These are called the pre
cordial leads or the chest leads today. In nineteen forty two,
(27:57):
New York cardiologist Emmanuel Goldberger also worked with the number
and types of leads, and that started moving toward the
twelve lead electro cardiogram that is most commonly used today.
There are also other numbers of leads that are used
for particular purposes, but like the most common standard in
a medical setting today is twelve leads. In nineteen forty eight,
(28:22):
Swedish engineer Runa Emquist, who had also trained as a physician,
developed the first inkjet ECG printer. He would also go
on to be a big part of the development of
the first implantable pacemaker. By the nineteen fifties, researchers were
working on finding ways to automate ECG readings. The development
(28:43):
of automated readings also made other life saving developments possible,
like automated external defibrillators, which automatically diagnose arrhythmias and then
deliver shocks only when they are warranted. Today, a lot
of ECGs are automatically analyzed before being reviewed by cardiologists, internists,
(29:03):
primary care doctors, or other medical professionals. The automation of
ECG readings was possible thanks to the advent of computers
and microprocessors, which have continued to have a huge role
in making electric cardiograph machines much smaller and easier to use.
In nineteen fifty seven, American biophysicist Norman Jeffrey's Halter developed
(29:25):
the dynamic ECG, often known as the Halter ECG or
a Halter monitor, which is a portable device that can
continually monitor a patient's heart for twenty four hours or more. Today,
Holter monitors are wearable devices, weighing a couple of pounds
at most, but they initially weighed about eighty three pounds
or thirty eight kilograms and had to be worn like
(29:47):
a huge heavy backpack. Magneto cardiograms were introduced in nineteen
sixty three, which could record heart rhythms without the patient
needing to have electrodes on their body. Very expensive, though,
so they never really took off. That same year, American
cardiologist Robert A. Bruce developed a protocol to record a
(30:08):
person's cardiac signals while they did progressively more intense exercise
on a treadmill that today is known as the Bruce protocol.
Speaker 1 (30:17):
And of course, ECGs have continued to evolve with changes
in technology. By nineteen ninety nine, there were twelve lead
ECGs that could send their results directly to handheld computers. Today,
there are a range of consumer ECG devices that are tiny,
everything from the ECG function on an Apple Watch to
(30:37):
a device the size of a credit card that communicates
with an app, to home devices that can record an
ECG and also measure a person's blood pressure. There are
pros and cons to all of these, a big one
being that while a twelve lead ECG is considered standard
in medical settings today, most of these home use models
only use one or two leads. The device or app
(31:01):
also typically interprets the ECG automatically and displays the results,
and that can lead to various false negatives or false positives.
Speaker 2 (31:10):
If you're me and you have an Apple Watch, it
could also be that the Apple to Watch just incessantly
starts over telling you like cycling through all the things
that thinks you're doing wrong, rather than ever fully recording
the ECG I've done a lot of troubleshooting on that
that has not been successful. I also have some listener
mail that is also somewhat medical related.
Speaker 1 (31:33):
It is from Edith.
Speaker 2 (31:35):
Edith says, Hi, Holly and Tracy. I've been wanting to
write forever, but never had anything I thought worthy of
writing about until now. So this will probably be a
combination of things I didn't think worthy but still want
to say, and a story. First of all, I'm writing
this while in the airport on a way from Boston
to Atlanta, which I find kind of funny and coincidental.
On my drive to the airport, I was listening to
(31:55):
the behind the scenes following the tetanus episode. More on
this later. That's the story, first of all, as a
fifty year old former theater kid who loves to sew,
has far too much clothing and too many pairs of shoes,
and doesn't like my body to be unexpectedly exposed to unpleasantness.
Slippers for the wind, Holly, I see you now. I
(32:18):
have to thank you for your unintentional PSA. I just
turned fifty in April and really had not thought about vaccinations.
I mean, I still think and maybe act like I'm thirty.
But when you all mentioned that we, yes, us are
of an age where we probably only got one measle shot,
I was like, huh, I did not know that, So
now I know to ask about that at my next physical.
Speaker 1 (32:37):
Thanks. Okay, okay, finally the story and the behind the scenes.
You both told stories about extra tetanus shots, so I
wanted to tell you about mine. I was in high
school in Cambridge, Massachusetts, and I did crew. Of course,
we rowed on the Charles River. One day when we
were putting the boats away, I somehow got caught in
a bad spot going around the corner and ended up
(32:57):
in the water. Now I know that the.
Speaker 2 (33:00):
Charles isn't thought of as very clean now, but back then,
well the things you would see floating there were bad.
So I fell in and that's how I ended up
getting a tetanus booster. I will pause and say that
the title of this email is love that dirty Water, Boston,
You're My Home, which is of course a song lyric reference,
referencing also the very dirtiness of both the.
Speaker 1 (33:23):
Charles and Boston Harbor at that time.
Speaker 2 (33:25):
Anyway, the email continues, anyway, I don't have any pets,
so I'm attaching a variety of collected animal pictures, including
a pig video, some horses from our neighbor's farm, an
old picture of my daughter and my brother in law's
old dog, and a current picture of my daughter on
a horse wor comparison. Thank you for all you do
as a former Medford resident. For the statement at the
(33:45):
beginning of the latest Unearthed episode, love you guys. I
tried but failed to keep it short, Edith, Edith, I
love this email. Regarding vaccinations. We had talked in I
think behind the scenes on the show about how I
was turning fifty. I knew that I meant that meant
that I was going to need to go and get
some vaccines that are recommended at the age of fifty.
I did do that those vaccines were shingles in newmacocle pneumonia.
(34:12):
I did both of those at the same time, because
somehow I thought that the people saying that sometimes the
shingles vaccine can make you feel a little unwell, I
just thought that might not apply to me, because I
am not known to have ever actually had chicken box,
but it is recommended at the age of fifty. Anyway,
(34:32):
I did feel I felt unwell. Still much better than
getting shingles or pneumonia. So yeah, that's done. I will
need shot two of the shingles shot a little bit later. Also,
lots of great animal pictures. Man, I love horse pictures.
They're so beautiful. Are a horse and a fold just
(34:54):
running through a field? Oh?
Speaker 1 (34:55):
Great? Is that?
Speaker 2 (34:57):
I don't think I'll watch the big video while we
are sitting here.
Speaker 1 (35:01):
I love a little pig action. You just reminded me
of the funniest thing I've ever seen a pig do
just now, have you ever seen a pig eat spaghetti? No,
our mutual friend, who is often prone to wacky high jinks,
(35:23):
briefly had a pig. I don't remember how she came
in to possession of the pig. She only had it
a brief period of time while she was rehoming it
and trying to find somebody that actually had like acreage
that they could raise a pig on. But in the meantime,
she and her amazing mother were just trying to keep
the pig fed and happy, and her mother started regularly
(35:43):
making the pig plates of spaghetti. It was the cutest
thing I ever saw in my life. I'm imagining what
it would look like, and it does seem very cute.
We were tiny at the time. He was still a piglet,
and so he would get the spaghetti all wound around
his snout and then try to chase it around the
house trying to get the spaghett Yeah. I wish this
were like a required thing that everybody could see in
(36:04):
their life because it brings so much joy.
Speaker 2 (36:06):
Yeah, because I am a fan of Game Changer, I
am imagining this pig wearing a tiny hat while eating
the he was not, so thank you so much for
this email, Edith, the Charles River is a lot cleaner
than it used to be. As somebody who moved to
(36:28):
the Boston area from elsewhere, I have a fondness for
seeing people rowing out on the river. I don't know
how local people feel about the rowers. I'm always a
little happy when I'm usually on the tee and I
go over the bridge and I'm like, oh, people rowing
out on the river. So, if you would like to
send us a note about this or any other podcast
or a history podcast at iHeartRadio dot com, and you
(36:52):
can subscribe to our show on the iHeartRadio app and
anywhere else if you like to et your podcasts. Stuff
you Missed in History Class is a production of iHeartRadio.
For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows.
Stuff You Missed in History Class News
Hosts And Creators
Holly Frey
Tracy Wilson
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