Pacemakers Got the Beat

whoa electrical impulses, Lauren, Now you're talking crazy talk. What do you mean electrical impulses. That's that's how the heart works. There's crazy there. We we we have natural pacemakers, and sometimes they work less well than others. But so yeah, so so. Pacemakers are are small devices that are implanted nearish the heart, in the general chest, airs, cavity, shoulder,

abdomen's where on there. They use low energy electrical impulses to help control any abnormal heart rhythms um sometimes called arrhythmias rhythmia. Thank you, I had an arrhythmia as a child, did you. Yep? I had an arrhythmia and a heart murmur. Wow that's exciting in the bad way. So anyway, so those can be that your heart is beating either too fast, too slow, or irregularly. And um, there are more long words for all of those things, which right now there's

there's a tachycardia there you go, yeah, and breda cardia. Yes, so those are the too so breda cardias if it's beating too slowly, and tachycardia is when it's too quickly. Sure, there's also other conditions that can that can wrap up into needing a pacemaker a k A. M. Atrial fibrilation in which the upper chambers of the heart kind of

quiver instead of really contracting. Yeah. So, in order for you to really understand what we're talking about here, the heart is divided up into four chambers right right, the left and right atria, which are the upper chambers, and the left and right ventricles, which are the lower chambers. Right, So the upper chamber chambers, the atria, when they when they contract, they force blood down into the ventricles, which then when they can try to force it throughout the

rest of the body. And so the combination of these two contractions are what we think of the heartbeat. The whole love dub dub is that. Yeah, So that's you know, the love the atria and the dub the ventricles, so you know that there's just plenty of room for romance. But so if if one of these is not working

out correctly, then it's it's a huge problem. Right. So, if the atria are doing this fibrillation where they are quivering instead of beating, then it's not providing the right amount of blood to the ventricles to pump it through the rest of the body. That's all obviously an issue, but there's another one too. Write there's also heart block, in which the electrical signal is slowed or disrupted as

it moves through the heart. So again the problem with actually the signal reaching the place where it needs to go so that you have a healthy heartbeat. Right. It's it's like if the cover on your wire is a little bit screwy something something to that extent, except the wires your heart and you need that wire pretty badly. Yeah, it's it's um. Unless you're the tin man, you pretty much need one. And these conditions can be caused by all kinds of disease and other wackiness that could be.

It could be an inherited condition, it can be after a heart attack, if if a heart attack damages the muscle, right, yeah, there are injuries that can end up injuring the heart as a as a result. Yeah. So there's lots of different ways that this could happen, including things like just coming out of a surgery that's unrelated to your heart. Sure, absolutely, Okay, So so what happens when your heart lacks rhythm? You can no longer do really crazy dances like the electric slide. Okay,

true enough. However, it mostly means that your body might not be getting enough blood, which would cause a tiredness, lightheadedness, breathlessness even like fainting, organ damage, and and can potentially even lead to death if it goes unchecked. Yeah. Yeah, so we're talking about very serious stuff. Now. A healthy adult has a heart rate at rest. That's what between sixty beats permant something like that. Ye ye, so um, mind's on the high end, which is actually not great.

It means that, honestly, that Jonathan needs to exercise more so that I have a healthier cardio life. And that's something that I am working on because it's a concern, right, I'm getting I'm getting to a certain age um physically if not mentally or emotionally, so I need to prepare for that. Generally, slower heartbeat within that range is is ideal. Um and healthy heartbeats are regular because we have, like

I said earlier, those built in pacemakers. Those are the sino ar trial I said that right, Yes, which at the at the at the upper right. Okay, gotcha. So yeah, so it's this is kind of the signal that lets the atria no to to contract. So once that signal goes through to contract the atria, what happens then, Like, how is it then move onto the ventricle um, it passes through another node, the atrio ventricular nod. Well, yeah, okay, cool.

So you've got two nodes that are doing this and they're doing it in a very precise rhythm so that it creates this contraction that that then pumps the blood through the rest of the body. All right, And if that's atrial node isn't working properly, the atrio ventricular node can take over for it. But it's a it's it's a weaker force, so it's not as efficient, it's not as efficient. It's only going to get you up to about forty beats per minute. Which, um, is why you're

going to encounter that fatigue and breathlessness and stuff like that. Right, So you'll you'll you'll live, but you'll be getting an increasingly poor condition. Um. So what do pacemakers do. Pacemakers can can regulate that they can help slow the rhythm of a too fast heartbeat or help control and a regular or too fast form or too slow them. So they can they can monitor the impulses and override it or pulses, I guess I should say, and override it so that it has a more regular heartbeat and keep

someone at an optimal heartbeat range. Right. Sure, And and if those if those two nodes are not communicating properly, a pacemaker can help coordinate the electrical signals between them. I see. So if maybe the cino ore atrial nodes working just fine, but perhaps the ventricular ones not, then this could help balance that balance that out right? Sure? And it does this because okay, So, so a pacemaker is essentially a very small generator hooked up to a

battery and a computer. Again, very small battery and very small computer. You have to be implant the sure um and wires are threaded from the pacemaker through a vein to the heart. Um. Those wires being tipped with electrodes, and the electrodes detect your heart's electrical activity and rhythm and then send that information to the computer which will monitor them. Um and then uh, it will direct the generator to fire whenever the signals go go wnkey all right.

So what the computer is doing is looking for any irregularities, share addresses that right. Um. It can also record these signals for your doctor to upload and used to adjust your pacemaker. Um using a wireless device. They don't have to do surgery on you and check it because they want to check it about quarterly, so that would be messy. So this is kind of like a very important version

of a physical activity tracker. It's keeping data on the activity of your heart and let your doctor know exactly what's going on right right um. In some cases, that onboard computer can even be accessed remotely via the interwebs. So for those of you who are privacy worried about that kind of thing, the idea that your heart rate

is being monitored remotely maybe not for you. I actually think I actually think it's super awesome, Like the idea that that a doctor would have that level of granular information about a pay stients health and and even be able to preemptively tell the patient, hey, I'm detecting some unusual readings here. Could you come in so that we can make sure that you are in good shape, that you're in good shape, and that it's not an equipment malfunction.

And you know, obviously that would be incredibly important. And if it were, you know, I mean there's some some people have pacemakers who are who are basically doing okay, it's more precautionary, and but there are other very life threatening ventricular diseases. Sure, sure, yeah, some models, called great responsive models will actually adjust to your heart rate to your changes in activity. Gotcha is like, which again makes sense.

For example, like if you're exerting yourself, then you might need a different heart rate than if you were at rest. And uh that's why I remember older pacemakers that was a real challenge because they would they would keep a very steady heart rate, which was great, but if you break into a brisk jug your heart wouldn't be able to to keep up when the in the computer would start misfire. Right, So that was a real issue. Sure sure, so, um,

So there are three basic types of pacemakers. You've got single chamber which carry impulses from the generator to the heart's right ventricle. Dual chamber which carry those impulses to the right ventricle and the right atrium um and and also helped coordinate the timing between the two. Then you've got bi ventricular which which carry those impulses to the right atrium and both ventricles helping coordinate all of the signals.

And uh, those are yeah for for as you can imagine, those those are increasing in seriousness right right, obviously because you're talking about having to take over more and more of the hearts activity. There are all there are also

related UM implantable cardio verter cardioverter did I say that right? Yes, implantable cardioverter defibrillators, which UM use not only those low energy impulses that a regular pacemaker would use, but also UM high high energy impulses when necessary to treat very life threatening So like if you're for example, there I'll t talk about some of the early ones of this, but there are some devices that let's say the detects at your heart that maybe you're going into cardiac arrest.

It can actually deliver a strong enough electrical impulse to possibly, you know, kickstart your heart going again. So it ends up being like you know, if you guys have ever seen any medical procedural, you have obviously seen the person with which they usually use incorrectly. Yeah, the clear part is important, by the way, Yes, but now he's doing

poorly from too much electric Um. Yeah, that's ah. This is something that's sort of an implantable device that does a similar thing, although it does it in a very precise way because it's delivering it directly to the heart and um and and not every pacemaker does this. Um. They can also, like Jonathan said earlier, be temporary if you've just had if you've just had a heart attack or surgery, or perhaps overdosed. While while the patient is in the hospital with these kinds of issues, they might

have a temporary pacemaker. UM. And of course the permanent ones, which is more what we've been talking about. I mean, they wouldn't implant a temporary one, right, Yeah. In fact, the earliest pacemakers are more like what you would see with a temporary pacemaker, I mean, far the temporary ones that we use now are far more sophisticated. Of course,

orders of magnitude more sophisticated. But the ideas that you would have an external device that would be able, you know, anyone could monitor and also be able to like a medical professional would be able to disconnect it once that was a viable option, and wires would go into you, which is kind of, you know, depending upon your level of comfort, a little squeaky, but I'm honestly pretty squeaked

out by the entire wire through a vein thing. Yeah. Well, just wait until we talk about the history of pacemakers, because it's going to get really interesting. I'm glad you took that research. So, in the case of permanent pacemakers, batteries and generators usually have to be replaced every five

to fifteen years, usually about six or seven. It's really the battery start running down, and they figure, while we're performing surgery on you, we might as well change out the generator to make sure that it doesn't start running down to right right, So that way, and it actually decreases the number of surgeries you would need over the lifetime.

Over your lifetime, right sure, yeah, the lifetime of the product, your lifetime, um and the wires may eventually need to be replaced as well, but that's that's more case to

case basis. Right now, we talked about in our Electronics and f A a episode about electromagnetic interference and even discussed a little bit about how people with pacemakers need to be careful around devices that emit E m I, which is pretty much anything that's electrical, right right, And that's because, like any electrical signal, the impulse is sent

by pacemaker can be disrupted by an electromagnetic field. Yeah. So, now, granted, in most cases, the instructions you get are pretty pretty common sense, and stuff like don't don't lay down and put a laptop computer or a cell phone or for your heart. Yeah you don't wanna, don't wanna have like your cell phone in your shirt pocket for example, right right, You know, avoid brushing up next to strong household appliances,

industrial welders. Don't lay directly against the microwave as you wait for that sweet sweet popcorn to be delivered to your hands. You know, keep keep it. Keep your generators. You're you're larger than your heart generator generator at arms length that don't use jackhammers kind of that kind of

I never do and everyone thanks me. Yeah, so's and you know, I mean, things like metal detectors are are fine if they're you know, I it's you're supposed to tell security agents like, hey, I've got this pacemaker thing, please kill me, and and they will know how to deal with that. Yeah. So it's it's certainly one of those things that does mean, you know, you have to

take that into account in your lifestyle. Sure, but it's also development that has, like we said, given a huge number of people a chance at a healthy life that otherwise they would not have. So it's it's phenomenal technology. We'll talk more about how we developed this technology over years and years of experimentation, some of which enters into the Frankenstein Mad Scientist realm. And I can't wait to talk about it. But before we do, let's take a

quick break to thank our sponsor. Now let's get back to talking about pacemakers. Now, in this particular episode, we kind of divided up the research of it, so Lauren ended up looking a lot at how the heart works and how pacemakers tend to work. If you guys have ever listened to for thinking, you know that I am the medical correspondent. Yeah. Yeah, we we make her look at all the squeaky stuff so we don't have to because she likes squeaky stuff like um. Although slime, I

would slime is really great, guys. Although I would I would argue glancing through your notes here for the history that you actually got the short end of the squick stage. You know what. This This is why never used the phrase quick stick. This is a This is entering into a realm that I actually relish, I because we're talking about a realm of scientific exploration that definitely goes on that mad scientist side of the scale. I mean, in

that really cool kind of Victorian era. And this this is the same era where we saw things like Mary Shelley's Frankenstein be published, and so that's you know, and and some of the stuff that was being talked about and discovered at this time plays into the narrative of that story, although in a much more kind of literary

way and not a scientific way. But at any rate, this is when we had people really thinking about electricity and its effect on the human body, and not just the human body as it turns out, So you really need to talk about the history of the pacemaker have to go all the way back to the mid seventeen hundreds. That's when it's when people started to experiment with what

they called electro stimulation, using electricity to stimulate muscles. Uh. And in fact, by this time they were looking at cardiac electro stimulation, so again using electricity to stimulate the heart. This was all in animals at the time. Yeah, So they would find recently dead animals, or they would make an animal recently dead, and then they would use some form of electricity to use on electricity source to stimulate

the animal's heart. Electric sources. Yeah, at the time, they had they had laden jars and voltaic piles peels Actually you should say voltaic peels. It's it's actually named uh it's yeah, so peel is French, but it's voltaic peels or piles if you prefer both of which we were. I mean our batteries. They are viable batteries, but very dangerous, yeah, and not particularly strong unless you make huge stacks. Right. So these are predecessors to what we consider the modern battery.

But that was when there was a lot of experimentation going on. So they would use them to stimulate the cardiac nerves and animals in an attempt to resuscitate intact dead animals and thus, as my notes say, infect the world with chipmunk zombies. Uh. So, there was a fellow named Luigi Galvani who was credited with proposing electricity as the mechanism that causes our muscles to operate. Now here's

the story. Uh, this is very possibly apocryphal, but the the story the legend that Galvani was working on on dissecting a little froggy and uh ended up building up an electrostatic charge and picked up a scalpel and touched the scalpel to the froggy and it discharged the electro static charge, which created the spark and made the froggy's leg twitch. Thus, Galvanni began to think of electricity as

being the means through which our muscles operate. He called it animal electricity, as opposed to what was being called heat electricity. So he's he thought that animal electricity was some sort of electricity trical type of fluid that would make muscles move. Before then, it was this idea of laden jars were still based on the principle that electricity was a fluid isn't that correct? Yeah, yeah, so we're you know, this is obviously this is the early days

of learning about electricity. So uh. At any rate that that research led other people to start to tinker around. One of those was William Hawes h A W. E. S. He established a society in London called the Humane Society. But it's not the Humane Society the way we would think of it in the United States. You hear the Humane Society and you think, oh, that's an animal rescue. It's not for adopting dogs and cats. Know, this was a a group that was dedicated to um well, salvaging

people who appeared to be dead. This was a big concern at the time a lot of people. You know, we didn't really have the more precise scientific definitions and even today's debatable of of what is alive and what is dead, and we you know, we didn't have heart rate monitors. It was a morbid time, really, it's what it was. It was a lot harder to tell and so there was a huge fear of getting buried alive. Yeah. So there was also a similar society at the time

in Paris. Paris, Uh, I assume Paris friends and not Paris, Texas. Eventually the organization would become the Royal Humane Society of London, and very early on during this society's days, scientists began to explore electro stimulation as a way of resuscitating people who appear to have died and maybe who are not

actually dead but could be revived. So se A guy named Charles Kite writes uh paper titled an Essay upon the Recovery of the Apparently Dead, which is already my favorite title of a of a paper since uh, since more wrote Cramming more components on integrated circuits. Um, I love, I love, I love these titles. They're better. That's the best kind of research, really. So, according to the essay, Ki used electro stimulation to treat a three year old child.

She had fallen out of a window and appeared to be dead. They had called in an apothecary, who was unable to do anything. Kite said that it was twenty minutes before he could arrive to provide some sort of

electro stimulation to the child's heart. He used his He used essentially electrodes to to deliver a gentle electrical shock to various parts of the child's body eventually setting on the thorax or chest really to uh and found that he got a pulse when he did that, and claimed that the child woke up was very groggy and uh and and confused about her surroundings, but that she eventually

made a full recovery. What that tells me is that this story is probably either exaggerated or there are some big missing components, Because being dead for twenty minutes is being dead is dead. You're not You're not You're not bouncing back from that really, But any rate, it could be that that no one at the house at the time could find a heartbeat, right, could have been that she had a very weak pulse interminute pulse. Even so,

at any rate, that's the story. From seventy six, a couple of Danish scientists published a paper that was titled Life Saving Measures for drowning persons and Information of the best means by which they can be brought back to life, and that also included electro stimulation of the heart as a means of saving people. We're gonna jump ahead, so a lot of people researching this. In eighteen twenty, Dr de Sanctus in The Medical Guide described the reanimation chair.

I didn't show you a picture of this yet, have I learned? You're gonna get a chance to see it on social as well. The chair included bellows which were meant to force air into the person's lungs, a metallic tube inserted into the person's esophagus, and a voltaic peel or pile, depending upon how you want to pronounce it, attached at one end of the metal tube and the other end was to an electrode. The electrode was then to quote regions of the heart, the diaphragm, and the

stomach end quote to cause muscles to contract. If you look at this thing, or illustrations of this thing, I should say I haven't seen a picture of what I don't know if one was ever actually built, but the illustrations of what it was supposed to look like look like it came from Hostile or Saw or one of those movies. It is absolutely terrified to behold. It makes a dentist chair look absolutely comforting by by comparison, I look forward to it. Yeah, experiments with electro puncture, this

is where we're really getting into the fun stuff. So that is that is combining electrical stimulation with acupuncture. So you've got a needle that you insert into the body of your your subject and then you shoot electricity through it to stimulate. Yeah, well animal, it was most animals, mostly dogs. Actually, uh yeah, I didn't want to dwell

on that too much because I love my doggies. So anyway, it turned out the early experiments anyway, it turned out to be i'll use the word failure, So no Frank and doggies. From this particular early experimentation, however, other people would start to experiment with using insulated needles that could deliver an electrical shock to a specific point, the point of the needle in fact, and that would in fact

be the basis for early pacemakers. Uh. They did discover that by refining this process that they could stimulate activity in a heart that was undergoing cardiac arrest. And again they were using animals, and essentially, in order to experiment, they would over a neesthetize animals in or to induce

cardiac arrest. So we would see more and more experiments between eighteen twenty eight and nineteen thirty, which is the next date I have on my my list, and I I don't want to be too exhaustive with this, and also and they get pretty weird. And uh yeah, when you start talking about getting cadavers from recent executions, it starts to get pretty grim. So I'm going to I'm gonna skip over that. We skip over the entire Victorian era. We skip over Jack the Ripper. Uh, listen to stuff

you missed in history class. They cover all that kind of stuff. All right, it's n That's when a fellow by name of Albert S. Hyman develops and patents the artificial pacemaker. Yeah, so this thing did not look like a pacemaker as you and I would would recognize if we were to see one, which are which are large coin sized. Yeah, they're they're in the Grand Scheme of Medical Devices. They are tiny. Uh, this one was not tiny.

This was a hand crank. Okay, So you had a hand crank and it had wires cables essentially that ended in needles that could be inserted into a person and by turning the hand crank. There was also a spring motor inside of it that turned a magneto, which is a d C current generator. So essentially what you're doing is you're turning We've talked about inducing electricity to flow by using moving a conductor through a fluctuating magnetic field. This is a way of doing that by hand. You

turn the cranks. It's turning it through this magnetic field. That's inducing electricity to throw to flow rather and that

ends up supplying the electricity needed for the pacemaker. The insulation needle would deliver the electric charge to the right atrium of the heart, and by March first, nineteen thirty two, the pacemaker had been used forty three times with a successful outcome in fourteen cases, which is about a thirty three percent success rate, which sounds incredibly low, but then keep in mind that the essentially this was an absolute last Yeah, this was the last last ditch effort to

try and revive someone. So it wasn't like this what These were not the type of pacemakers we've talked about in our episode where we talked about the things that you would have in your in your chest for a prolonged period. This was really meant to revive someone. Yeah, so this is this is a little different thing. Patient

saved is actually better and zero percent. So, uh, nineteen forties, that's when they started to Engineers and doctors began to work on designing defibrillators, which, as we said, can play a part in some types of pacemakers that you can find today that are it's kind of a combination device really.

Nine an elderly man who in the literature is called h N. They don't obviously identify people because it's medical, but h N suffered heart ailments for several years, had had heart attacks and other irregularities, and became the recipient of atronic products. Nine O two M battery operated pacemaker. This was not an internal unit. It was not an

implant in that sense. They did implant the electrodes so that they had contact with the heart, but the cables to the actual device were external, and you would, you know, have to carry the pacemaker around with you and it was held outside the body. You know. It could also detect spont aneas cardiac activity. It had essentially had the ability to tell if something was going wrong. It wasn't necessarily able to respond to that dynamically, but it could

at least warn a caregiver that something something was happening. Um, everything was it was, It worked all right. The one problem was that the area where the electrodes would go in through the skin Essentially the needle would go in through the skin um was prone to minor infections. There was never like that you would expect from from I mean, and that's part of the reason why the drive should

create implantable rightmakers exist. And we talked about, you know, the fact that in our piercing episode or our body modification episode, we talked about that there is a a possibility of developing these kind of infections and they may not be serious, it may not be life threatening, but they can be problematic. And that was exactly what he had experienced. It wasn't an infection that was developing into sepsis, but it was like he would have to have the

area ened regularly so that he could clear out any infection. UH. In late nineteen sixty two, he underwent surgery for a pacemaker implant, but he never fully recovered. In fact, he never recovered from the surgical procedure. He died twenty days after the surgical procedure, So that was an unfortunate tragedy there, but he did have lived for several years with this

external pacemaker. In nineteen sixty doctor Robert Rubio implant a pacemaker into a female patient and that pacemaker was fifty two point five millimeters in diameter, which is about two inches uh seventeen point five millimeters thick, which is about point seven inches, so just over half an inch, and waged sixty four point three grams or two point three

ounces or less than a quarter of a pound. Now that one got power from two rechargeable nickel cadmium batteries which were charged through induction from an external flexible coil placed on the skin over the pacemaker. So this is the way some pacemakers are recharged today using a similar approach, although it's usually radio frequencies. But what we're talking about wireless power here right where you can induce this charging

through um again, your your cree. It's all about magnetic fields and electricity is really what we get down to. So you would have to place this flexible coil directly over your heart in order to recharge the pacemaker, or really directly over the pacemaker wherever the pacemaker was located, wherever the you know, the battery was uh. The stimulated electrode for this was a platinum disk, so it was

an expensive piece of medical technology. But sadly the patient died nine and a half months after the surgery, because she did develop an infection which turned into sepsis after the surgery. So the pacemaker was working, but the it was a side effect of the surgery. She unfortunately perished from that. So early implannable pacemakers varied widely and how long they could operate before requiring a recharge. So one of them would only go like eight hours and then

you have to recharge it. That's pretty yeah, that's pretty yeah. But there were others that could go weeks or even months before a recharge, even in the early days in the sixties. Uh this this also, I mean still today, how much how much your your pacemaker is actually needing to to create a charge will make your battery life very right. So in other words, in other words, if if it's only occasionally having to intervene, then you're recharging, may you may not need to recharge it as frequently

as someone where it's more active more frequently. Um So, in the nineteen sixties, that's when we started to see the cardiac stimulator defibrillators, which we kind of talked about. It's under called something else today, but same sort of idea that the device that can uh detect when a heart beat stops and then try to restart it with a controlled electrical burst to the heart. Uh. The early versions of that were also not implantable. They were external

as well. But now we've got implantable ones that are incorporated with sort of pacemaker technology. UM. Now, as far as the future goes, because from the nineteen sixties on to the present, it was really refining that process. It's just that miniaturization and in electrical stimulation yep, yep, making sure that we were getting more precise and smaller. Those are really the trends. So anything from nineteen sixties on

is more about refining that that design. Uh. Talking about the future, miniaturization is going to continue to be a factor. In fact, there are companies right now that are trying to create pacemakers that are about the size of a pill. So that tiny. So the reason why you want this is not just because it it takes up less space in the patient. Really, it's because the surgical procedures become

less invasive. It's less damaged to the body, less chance for infection, UH, makes it less chance for something to go wrong, because you're it's just it's just a smaller surgical procedure. So that's really where we're seeing the future come in as far as Pacemakers are concerned. And now that kind of wraps up our our episode. We were really interested in this topic. It was kind of it's it's always fun for us to take a specific technology and explain how it works and really where it came from.

We love doing that. I mean we obviously we love doing things like covering various companies as well. Uh, not to mention the fact that we have covered many, many, many personalities in technology. But if you guys want to hear us do more of this sort of thing, then I recommend you right in and let us know. So

send us a message. You can write us an email that addresses tech stuff at Discovery dot com, where you can find us on Tumbler or Facebook or Twitter with the handle text stuff hs W and who knows, you know, we may take your your suggestion. This suggestion, by the way, came to us from a listener right Facebook, from Peter. So, Peter,

I hope you enjoyed this episode about Pacemakers. I hope you were not asking about Jerry and the Pacemakers, because that's a band and they did very Across the Mercy, which is a great song but not what we covered. So hopefully we met your expectations. Let us know if we didn't. And guys, that wraps this up. We will talk to you again really soon for more on this and thousands of other topics. Is it how stuff works dot com