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