8 ms·

You really should not. 60 beats per minute means that in ten years the leads of a pacemaker will be bent 315 million times. That's an order of magnitude hig

You really should not. 60 beats per minute means that in ten years the leads of a pacemaker will be bent *315 million* times. That's an order of magnitude higher than we typically test fatigue resistance, and even if we were that confident about being able to produce flawless materials, there are millions of different enzymes and acids and temperature fluctuations in the body. Any one of those could impact the fatigue resistance. Additionally, any kind of implanted device is significantly prone to a wide range of problems that range from inconvenient to devastating. The human body is very hostile to foreign objects, often with few warning signs. Clots and fibrous capsules (and eventually, calcified capsules) form around ANY implant, and that's the best case problem. Titanium is extremely biocompatible. It forms a thinner capsule than most materials. It integrates with bones beautifully, due to surface treatments that allow bone to grow into microscopic surface cavities, with strong molecular bonds. But also sometimes, for no apparent reason, all the bone around a titanium implant will just start dying and resorbing. It's rare, but if you get a hip replacement you absolutely need to check on it regularly because if you don't you'll lose use of the leg completely (and quickly, and permanently). In and around the heart is one of the most challenging places to implant things, aside from maybe the brain. Any moving part of the body will constantly stress any mechanical part, and build up scar tissue around and rubbing spots. The only reason the brain is worse is because its fragile and changes size significantly when you sleep. Recently we started using leadless pacemakers. Even before that pacemakers were continually getting smaller, and smaller pacemakers are less irritating and experience less stress and movement. Even if that weren't true, it would still be worth checking in on pacemakers, because they're doing incredibly hard jobs and if they fail people can die faster than they can get to a hospital. EDIT: oh, and heart disease is the #1 cause of death in the US, while heart surgery is one of the most difficult specialties to get in to. They are absolutely never short on patients, lol.

NikolaNovak 4y ago
>>"changes size significantly when you sleep." Wait,what??
- fennecfoxen 4y ago
  Brain neurons going into sleep mode eject some of the cell contents and shrink, which apparently also helps flush waste because the cerebrospinal fluid can flow better.
R0b0t1 4y ago
> EDIT: oh, and heart disease is the #1 cause of death in the US, while heart surgery is one of the most difficult specialties to get in to. They are absolutely never short on patients, lol. This is still relevant to his concern, but from the other end. They might be making the labor artificially scarce to increase pay.
- ampdepolymerase 4y ago
  > This is still relevant to his concern, but from the other end. They might be making the labor artificially scarce to increase pay. This is very much true. I find that a lot of people in tech seem to put healthcare on a pedestal and believe that the professionalisation and gatekeeping of the industry create a better outcome than other engineering fields. This is very much untrue, the healthcare field is in need of massive disruption and lobbying to increase labor supply. You are being downvoted because a lot of tech people here hate to imagine that healthcare at the highest level is still subject to market forces like everything else. Medical training is being severely gatekept and hindered via the current apprenticeship/residency system. After all, we call the worst medical student, doctor. If you want to improve healthcare, tie medical school admission to the MCAT score, and only the MCAT score. You are not going to get better doctors just because candidates spend their summers building houses in some impoverished third world country.
  - zaroth 4y ago
    I live near Boston which is known for its medical centers, so this might skew things somewhat, but it seems like every graduate I know is going into medicine of some form (surgery, anesthesia, nursing, surgical tech, hospice, etc. etc.) I heard consistently that residency slots are extremely competitive and a lot of qualified candidates get passed over. The more I learn about the process the more insane it seems. From the student perspective you go from paying to work one day and spending most your time working cases with zero relevance to your actual specialty, to raking in several hundred thousand a year. It also seems like hospital systems seem to spend more than half their capacity either dealing with patients that don’t need to be there but there’s literally no place to send them, or patients that are too far gone and untreatable but there’s literally no place to send them. Healthcare is like a Gordian knot of terrible policies cemented into place by trillions of dollars of government spending.
furyofantares 4y ago
It's a weird argument, though, that we should be checking in on the state of the patient & these devices, but we don't do it unless we have the additional problem of needing to replace a battery.
- ethbr0 4y ago
  I'd think cert expiration would have taught all of us that out of sight and working is out of a busy, multitasking mind.
- sgtnoodle 4y ago
  Modern devices provide a wealth of telemetry completely autonomously. My pacemaker talks at least daily to a UFO shaped brick on my night stand via BLE. The brick has an integrated cell modem, and was given to me pre-configured. It has a bright green light (that turns off in the dark) to show that it's functional. It has a single button I have never pressed, for if I think something notable enough happened that my doctor's office needs to be sent a report sooner than every 90 days or so.
nousermane 4y ago
> 315 million times. That's an order of magnitude higher than we typically test fatigue resistance Nah, it's not that bad. Decent mechanical keyboard switch is specified for 100 million clicks [1, or google for "switch million actuations"]. Surely good engineering can eek out another order of magnitude. Not to mention - pacemaker leads ("wires"), the only part that bends, have way less stress on them (= larger bend radius) compared to a keyboard switch. Oh, and technology of multi-strand wire for redundancy is a very well established and understood one. [1] https://cdn-shop.adafruit.com/product-files/4974/EN_CHERRY_MX_BROWN.pdf https://cdn-shop.adafruit.com/product-files/4974/EN_CHERRY_M...
- insane_dreamer 4y ago
  non-comparable operating environments
- ceeplusplus 4y ago
  I've had Cherry switches fail right as the keyboard's warranty was up. The switch feels soft after wearing out, it gets dust in it and starts double typing, etc. Pacemakers need to be 100% reliable, not 99.9%.
- formerly_proven 4y ago
  Seen way too many failed Cherry MX (OG, vintage and third-party) switches to believe that.
- cududa 4y ago
  The absolutely arrogance to assume a keyboard switch and a pace maker are anywhere near the same thing…
  - tom_ 4y ago
    Indeed, the keyboard switch people have to produce a device that's manufacturable at scale for pennies per unit, and can be fitted in unforgiving environments by the untrained.
    - deleted 4y ago
sgtnoodle 4y ago
It sounds like you have quite a bit of knowledge on the subject. I had to get a pacemaker a couple years ago, and am an embedded engineer. I hope to live another 50 years at least, so this is an interesting subject for me. Maybe my cardiologist is just trying to make me feel good, but he says my leads will likely last 30-50 years. Intuitively that seems unlikely, but we'll see. It's got to be one of the most engineered cables in existence. The leadless pacemakers are indeed a technical marvel, but they aren't yet nearly as feature packed as shoulder implanted devices. They'll keep your heart from stopping if your nerves are flaky from time to time, but they don't have the energy storage to do much more than that. Mine monitors every single beat my heart takes, and automatically reports issues to my doctor via BLE. (Is bluetooth more or less scary than radioactive isotopes mounted in your body?) For about 8 months, my AV nerves were completely broken, and the pacemaker paced my ventricles 100% of the time. It was a nearly perfect drop-in replacement for the failed nerves. A leadless pacemaker wouldn't have had nearly the same performance. My nerves eventually started mostly working again, and now I'm on track to have a battery life pushing 15 years. It would of course be great for the technology to advance even more over the next decade. Since my nerves mostly healed, a leadless device with a 30+ year battery life would be a nice replacement. With a shorter battery life, I don't really want to be collecting them in my heart (they don't plan to remove leadless pacemakers when they die.) I'm hoping by the time my current device is worn out, it will have logged enough telemetry for me to convince my cardiologist that I don't need a pacemaker at all, though.
- samstave 4y ago
  - sgtnoodle 4y ago
    Lol. I've certainly already made the joke that embedded systems are dear to my heart. I'd consider working a few years at a place like Medtronic just to see what I can contribute, but on the other hand I hear there's roughly a 2:1 ratio between requirements and lines of code. Going through airport security is fun just because the TSA agents overreact as if the metal detector is going to kill me.
rudididdjdh 4y ago
All of this sounds fine in theory as an explanation but was material fatigue actually why the technology was abandoned? Like you say, those complications are rare and the section that was quoted by the other commenter seems to imply that the opportunity to upgrade the patient's hardware was the real motivator (since obviously the opportunity to swap batteries wasn't a factor for the nuclear variant). It seems more like a question of if regular upgrades produce results significant enough to justify opening the patient up again after implanaing what's currently state of the art. Or is surgery obligatory in either case?
rvba 4y ago
But didnt the poster above wrtite that the older designs can survive those 315 millions of beats?
Perenti 4y ago
I have an ICD, and have had to have two lead revisions, once when the lead failed to implant, and the second when it cracked. My resting pulse is 100bpm, and the device overpaces me if I exceed 140bpm (unless having sex, when it kicks in at 220bpm. Is this so I'll die happy?). So in ten years my leads cop at least 500 million bends. Since my device does cardioversion and defibrillation there's no way a wireless implant in the atrium and ventricle will work. The doctors keep quoting figures of how reliable this tech is, but I've had 3 procedures due to device failure in the last 5 years.

You really should not. 60 beats per minute means that in ten years the leads of a pacemaker will be bent *315 million* times. That's an order of magnitude hig

NikolaNovak 4y ago

>>"changes size significantly when you sleep." Wait,what??

fennecfoxen 4y ago
Brain neurons going into sleep mode eject some of the cell contents and shrink, which apparently also helps flush waste because the cerebrospinal fluid can flow better.

R0b0t1 4y ago

> EDIT: oh, and heart disease is the #1 cause of death in the US, while heart surgery is one of the most difficult specialties to get in to. They are absolutely never short on patients, lol. This is still relevant to his concern, but from the other end. They might be making the labor artificially scarce to increase pay.

ampdepolymerase 4y ago
> This is still relevant to his concern, but from the other end. They might be making the labor artificially scarce to increase pay. This is very much true. I find that a lot of people in tech seem to put healthcare on a pedestal and believe that the professionalisation and gatekeeping of the industry create a better outcome than other engineering fields. This is very much untrue, the healthcare field is in need of massive disruption and lobbying to increase labor supply. You are being downvoted because a lot of tech people here hate to imagine that healthcare at the highest level is still subject to market forces like everything else. Medical training is being severely gatekept and hindered via the current apprenticeship/residency system. After all, we call the worst medical student, doctor. If you want to improve healthcare, tie medical school admission to the MCAT score, and only the MCAT score. You are not going to get better doctors just because candidates spend their summers building houses in some impoverished third world country.
- zaroth 4y ago
  I live near Boston which is known for its medical centers, so this might skew things somewhat, but it seems like every graduate I know is going into medicine of some form (surgery, anesthesia, nursing, surgical tech, hospice, etc. etc.) I heard consistently that residency slots are extremely competitive and a lot of qualified candidates get passed over. The more I learn about the process the more insane it seems. From the student perspective you go from paying to work one day and spending most your time working cases with zero relevance to your actual specialty, to raking in several hundred thousand a year. It also seems like hospital systems seem to spend more than half their capacity either dealing with patients that don’t need to be there but there’s literally no place to send them, or patients that are too far gone and untreatable but there’s literally no place to send them. Healthcare is like a Gordian knot of terrible policies cemented into place by trillions of dollars of government spending.

furyofantares 4y ago

It's a weird argument, though, that we should be checking in on the state of the patient & these devices, but we don't do it unless we have the additional problem of needing to replace a battery.

ethbr0 4y ago
I'd think cert expiration would have taught all of us that out of sight and working is out of a busy, multitasking mind.
sgtnoodle 4y ago
Modern devices provide a wealth of telemetry completely autonomously. My pacemaker talks at least daily to a UFO shaped brick on my night stand via BLE. The brick has an integrated cell modem, and was given to me pre-configured. It has a bright green light (that turns off in the dark) to show that it's functional. It has a single button I have never pressed, for if I think something notable enough happened that my doctor's office needs to be sent a report sooner than every 90 days or so.

nousermane 4y ago

> 315 million times. That's an order of magnitude higher than we typically test fatigue resistance Nah, it's not that bad. Decent mechanical keyboard switch is specified for 100 million clicks [1, or google for "switch million actuations"]. Surely good engineering can eek out another order of magnitude. Not to mention - pacemaker leads ("wires"), the only part that bends, have way less stress on them (= larger bend radius) compared to a keyboard switch. Oh, and technology of multi-strand wire for redundancy is a very well established and understood one. [1] https://cdn-shop.adafruit.com/product-files/4974/EN_CHERRY_MX_BROWN.pdf https://cdn-shop.adafruit.com/product-files/4974/EN_CHERRY_M...

insane_dreamer 4y ago
non-comparable operating environments
ceeplusplus 4y ago
I've had Cherry switches fail right as the keyboard's warranty was up. The switch feels soft after wearing out, it gets dust in it and starts double typing, etc. Pacemakers need to be 100% reliable, not 99.9%.
formerly_proven 4y ago
Seen way too many failed Cherry MX (OG, vintage and third-party) switches to believe that.
cududa 4y ago
The absolutely arrogance to assume a keyboard switch and a pace maker are anywhere near the same thing…
- tom_ 4y ago
  Indeed, the keyboard switch people have to produce a device that's manufacturable at scale for pennies per unit, and can be fitted in unforgiving environments by the untrained.
  - deleted 4y ago

sgtnoodle 4y ago

It sounds like you have quite a bit of knowledge on the subject. I had to get a pacemaker a couple years ago, and am an embedded engineer. I hope to live another 50 years at least, so this is an interesting subject for me. Maybe my cardiologist is just trying to make me feel good, but he says my leads will likely last 30-50 years. Intuitively that seems unlikely, but we'll see. It's got to be one of the most engineered cables in existence. The leadless pacemakers are indeed a technical marvel, but they aren't yet nearly as feature packed as shoulder implanted devices. They'll keep your heart from stopping if your nerves are flaky from time to time, but they don't have the energy storage to do much more than that. Mine monitors every single beat my heart takes, and automatically reports issues to my doctor via BLE. (Is bluetooth more or less scary than radioactive isotopes mounted in your body?) For about 8 months, my AV nerves were completely broken, and the pacemaker paced my ventricles 100% of the time. It was a nearly perfect drop-in replacement for the failed nerves. A leadless pacemaker wouldn't have had nearly the same performance. My nerves eventually started mostly working again, and now I'm on track to have a battery life pushing 15 years. It would of course be great for the technology to advance even more over the next decade. Since my nerves mostly healed, a leadless device with a 30+ year battery life would be a nice replacement. With a shorter battery life, I don't really want to be collecting them in my heart (they don't plan to remove leadless pacemakers when they die.) I'm hoping by the time my current device is worn out, it will have logged enough telemetry for me to convince my cardiologist that I don't need a pacemaker at all, though.

samstave 4y ago
- sgtnoodle 4y ago
  Lol. I've certainly already made the joke that embedded systems are dear to my heart. I'd consider working a few years at a place like Medtronic just to see what I can contribute, but on the other hand I hear there's roughly a 2:1 ratio between requirements and lines of code. Going through airport security is fun just because the TSA agents overreact as if the metal detector is going to kill me.

rudididdjdh 4y ago

All of this sounds fine in theory as an explanation but was material fatigue actually why the technology was abandoned? Like you say, those complications are rare and the section that was quoted by the other commenter seems to imply that the opportunity to upgrade the patient's hardware was the real motivator (since obviously the opportunity to swap batteries wasn't a factor for the nuclear variant). It seems more like a question of if regular upgrades produce results significant enough to justify opening the patient up again after implanaing what's currently state of the art. Or is surgery obligatory in either case?

rvba 4y ago

But didnt the poster above wrtite that the older designs can survive those 315 millions of beats?

Perenti 4y ago

I have an ICD, and have had to have two lead revisions, once when the lead failed to implant, and the second when it cracked. My resting pulse is 100bpm, and the device overpaces me if I exceed 140bpm (unless having sex, when it kicks in at 220bpm. Is this so I'll die happy?). So in ten years my leads cop at least 500 million bends. Since my device does cardioversion and defibrillation there's no way a wireless implant in the atrium and ventricle will work. The doctors keep quoting figures of how reliable this tech is, but I've had 3 procedures due to device failure in the last 5 years.