7 ms·

The 50-year quest to build a mechanical heart

58 points by fisherjeff 11y ago

sithadmin 11y ago
I find myself consistently in awe of the accomplishments that engineers working on implantable medical devices manage to yield. This is not only because of the remarkable impact that these devices often have on a patient's quality of life, but also because of the seemingly insurmountable number of hurdles that must be overcome to bring a functional product to market. For moral and regulatory reasons, these engineers cannot depend on large trial groups, the ability to rapidly iterate designs, run A/B trials, or exact much control over the quality and consistency of their sample subjects. And to top it all off, the nuances of human body systems are still very much 'black boxes' (in spite of our considerable and rapid advances in the field). From a business perspective, many of these efforts are viewed as nearly untouchable due to the levels of risk involved. Yet, things like the artificial hearts mentioned in this article still manage to get developed. They're not perfect, but they're damn impressive.
- mmmBacon 11y ago
  I worked on wearable sensing technology over the last couple years. Coming from a pure EE/Physics type background it was a real eye-opener to deal with the variability in human physiology. Even in the simplest sensors, it's nearly impossible to account for all the variability one encounters in the entirety of human population. Basically you always have a percentage of the population that your device just won't work on. I can only imagine the difficulty in building a device like an artificial heart. The fact that these artificial hearts work at all for any length of time is really a marvel of modern engineering and science.
lujim 11y ago
A bit stressful to read but amazing. I can't imagine having to endure surgeries where there is a relatively large risk that you won't wake up. If you do wake up there can be malfunctions in the device that can flip you off like a light switch. One patient remarked "I have never felt so good" then a short time later died due to a motor malfunction.
erobbins 11y ago
I remember watching the first Jarvik 7 transplant on PBS as a kid, thinking that by the time I was an adult it would be a routine procedure and how amazing that was. Reality kicked in of course. It's always surprised me that an artificial heart is so difficult to perfect. The heart is probably the simplest organ in the body, yet the devil is in the details.
- SeanDav 11y ago
  Simple yes, it is just a pump - but it has to be 100% reliable, every time, all the time, no downtime, for 70+ years. Just a few seconds of malfunction in all that time and you are likely dead. Amazing bit of kit - I am quite attached to mine.
  - trhway 11y ago
    >but it has to be 100% reliable, every time, all the time, no downtime, for 70+ years. this is why it looks kind of yesterday to me (like many things in the other highly regulated industry - aviation - too) - why 100% requirement for one device? How about "horizontal scaling" - have 2 of them or 3 smaller and less reliable ones. Once one failed - that is a signal to promptly go in for the "service". Replicating biology is a start, yet machinery has different advantages and disadvantages, so mechanical heart doesn't have to be a mechanical copy of the biological one. For example one can imagine having smaller helper pumps installed on all the big arteries, like near the groin for legs and near armpits for arms - that would improve the circulation and decrease the physical load on central arteries and overall energy consumption compare to the original biological schema of one central pump.
    - Kalium 11y ago
      I should think that emulating biology does the best job of cutting back on extra difficulties introduced by trying to outsmart biology.
    - mikeash 11y ago
      There are a couple of problems with that approach. One is that if you're going to have three-way redundancy, then each one has to be one-third the size to still fit, which adds to the engineering challenge and may well make reliability worse. Another is that not all failures can be fixed with redundancy. If one of your redundant hearts stops pumping, that's fine. But if it fails by, say, dumping all your blood into your chest cavity, then adding redundant hearts increases your chance of death, rather than decreasing it. Since you mentioned airplanes, making sure redundancy reduces rather than increasing risk is a big issue. For example, single-engine airplanes are prone to crashes due to engine failure. The solution is to add a second engine and you're much safer, right? Except that twin-engine planes can be very challenging to fly with a dead engine, and if you're not very careful with design and training, you'll end up with an airplane with two engines that crashes if either engine fails, greatly increasing the probability of a failure rather than decreasing it.
zachrose 11y ago
Would it be possible to temporarily power your own artificial heart with skeletal muscle? For example, by turning a crank attached to an artificial heart?
- sithadmin 11y ago
  Seems like it could be, given proper controls to ensure relatively regular pumping action (gearbox?). Pneumatic systems could probably be operated with a bellows of sorts.
  - ethbro 11y ago
    ... I think I just read the beginning of the best steampunk story ever.
- vacri 11y ago
  One of the problems for this is then how do you mount the heart? The human body isn't great for hardpoints. Yes, you can screw in stiffening devices, but for something that is meant to move, it gets a lot harder. Cranking a box requires that the box be locked in place, or it will move with the crank. The 'heartbox' in such a case can't be easily attached to ribs, as these move relative to each other, or to the spine. And that's the end of hardpoints in the chest. You might be able to put the pump somewhere else (pelvis?) but now you're affecting other organs as well. On top of all this, skeletal muscle tires quickly. A pump bulb arrangement might be better than a crank, but it's still the case that voluntary muscle movement isn't really designed for extended rhythmic use (eg: runners have to train a lot to be able to sustain running for any length of time)
Mz 11y ago
Excerpts: "This doesn’t only take from your body, it takes from your mind, spirit, and soul," De La Cruz says. And: Perhaps the biggest moral conundrum, though, has nothing to do with living with a mechanical heart, but dying with one. Unlike biological hearts, artificial ones can pump blood throughout the body and oxygen to the brain when the rest of the body breaks down. Death is dragged out — and may require the machine be shut off. "I’ve had patients where the liver and kidney failed, the skin turned yellow and died, and the only thing working normally was the brain," Arabia says. I find stuff like this incredibly disturbing. I always find myself wondering why doctors don't spend more time on helping people keep their own organs functioning instead of on this kind of stuff. I find this very scary. "Resistance is futile. You will be assimilated."...because we are only going to offer you something Frankensteinian like this and not offer better options for healing the tissues you were born with. I have a condition that accounts for a high percentage of lung transplants. So this stuff hits rather close to home for me.
- oldmanjay 11y ago
  > I always find myself wondering why doctors don't spend more time on helping people keep their own organs functioning instead of on this kind of stuff They almost certainly do. It's a pure anecdote, of course, but I've had doctors in many states throughout the US and to a one, they communicate information intended to help me maintain better health as a preventative measure. If you mean that doctors should spend effort on better treatments for failing organs, there are a number of projects working in those directions right now. Basically, I'm not sure what is disturbing you.
  - Mz 11y ago
    Basically, I'm not sure what is disturbing you. I hesitated to reply to you at all. You kind of waved off my concerns and didn't really ask a question. So I am concerned that replying is a mistake. But I seem to be damned no matter what I do when it comes to topics like this. I mean, why did you reply? The manner in which you replied seems pretty dismissive, given that I closed with a statement that I have a condition where transplants are common. But assuming you answered in good faith and just honestly don't see how bad your reply could sound to me, here is what disturbs me: If you have certain conditions, doctors don't really try to help you maintain better health. They chalk up bad outcomes to your official diagnosis and kind of wash their hands of trying harder. Then heroic interventions, like transplants, get all kinds of glowing press. When you get listed for transplant, you basically sit around waiting for someone relatively young and healthy to die tragically in an accident so you can have a second shot at life. I can't imagine the toll that takes on your psyche. That isn't a criticism of patients who accept the only option they are really being offered. But I think we can do better than that, and real quality of life is being given short shrift as medical professionals zealously pursue the "Ooh, shiny!" options that will get them impressive headlines. I also understand the pressures on them which lead to that, but it is the patients who suffer horribly because of it. It just makes me think something is very, very broken. And no one cares to even discuss that, much less try to fix it.
brc 11y ago
The article only briefly mentions it, but the future looks like pulse less continuous flow hearts. This one http://bivacor.com http://bivacor.com uses magnetic levitation to eliminate wear surfaces and needs no external air pump like the ones in the article.
- esturk 11y ago
  I'd heard about this a few years back but there's been no progress since about any clinical trials. Since the articles mentions SynCardia as the only artificial heart company approved by the FDA, I'm guessing the BiVACOR is still not ready?

58 points by fisherjeff 11y ago

I find myself consistently in awe of the accomplishments that engineers working on implantable medical devices manage to yield. This is not only because of the remarkable impact that these devices often have on a patient's quality of life, but also because of the seemingly insurmountable number of hurdles that must be overcome to bring a functional product to market. For moral and regulatory reasons, these engineers cannot depend on large trial groups, the ability to rapidly iterate designs, run A/B trials, or exact much control over the quality and consistency of their sample subjects. And to top it all off, the nuances of human body systems are still very much 'black boxes' (in spite of our considerable and rapid advances in the field). From a business perspective, many of these efforts are viewed as nearly untouchable due to the levels of risk involved. Yet, things like the artificial hearts mentioned in this article still manage to get developed. They're not perfect, but they're damn impressive.

mmmBacon 11y ago
I worked on wearable sensing technology over the last couple years. Coming from a pure EE/Physics type background it was a real eye-opener to deal with the variability in human physiology. Even in the simplest sensors, it's nearly impossible to account for all the variability one encounters in the entirety of human population. Basically you always have a percentage of the population that your device just won't work on. I can only imagine the difficulty in building a device like an artificial heart. The fact that these artificial hearts work at all for any length of time is really a marvel of modern engineering and science.

lujim 11y ago

A bit stressful to read but amazing. I can't imagine having to endure surgeries where there is a relatively large risk that you won't wake up. If you do wake up there can be malfunctions in the device that can flip you off like a light switch. One patient remarked "I have never felt so good" then a short time later died due to a motor malfunction.

erobbins 11y ago

I remember watching the first Jarvik 7 transplant on PBS as a kid, thinking that by the time I was an adult it would be a routine procedure and how amazing that was. Reality kicked in of course. It's always surprised me that an artificial heart is so difficult to perfect. The heart is probably the simplest organ in the body, yet the devil is in the details.

SeanDav 11y ago
Simple yes, it is just a pump - but it has to be 100% reliable, every time, all the time, no downtime, for 70+ years. Just a few seconds of malfunction in all that time and you are likely dead. Amazing bit of kit - I am quite attached to mine.
- trhway 11y ago
  >but it has to be 100% reliable, every time, all the time, no downtime, for 70+ years. this is why it looks kind of yesterday to me (like many things in the other highly regulated industry - aviation - too) - why 100% requirement for one device? How about "horizontal scaling" - have 2 of them or 3 smaller and less reliable ones. Once one failed - that is a signal to promptly go in for the "service". Replicating biology is a start, yet machinery has different advantages and disadvantages, so mechanical heart doesn't have to be a mechanical copy of the biological one. For example one can imagine having smaller helper pumps installed on all the big arteries, like near the groin for legs and near armpits for arms - that would improve the circulation and decrease the physical load on central arteries and overall energy consumption compare to the original biological schema of one central pump.
  - Kalium 11y ago
    I should think that emulating biology does the best job of cutting back on extra difficulties introduced by trying to outsmart biology.
  - mikeash 11y ago
    There are a couple of problems with that approach. One is that if you're going to have three-way redundancy, then each one has to be one-third the size to still fit, which adds to the engineering challenge and may well make reliability worse. Another is that not all failures can be fixed with redundancy. If one of your redundant hearts stops pumping, that's fine. But if it fails by, say, dumping all your blood into your chest cavity, then adding redundant hearts increases your chance of death, rather than decreasing it. Since you mentioned airplanes, making sure redundancy reduces rather than increasing risk is a big issue. For example, single-engine airplanes are prone to crashes due to engine failure. The solution is to add a second engine and you're much safer, right? Except that twin-engine planes can be very challenging to fly with a dead engine, and if you're not very careful with design and training, you'll end up with an airplane with two engines that crashes if either engine fails, greatly increasing the probability of a failure rather than decreasing it.

zachrose 11y ago

Would it be possible to temporarily power your own artificial heart with skeletal muscle? For example, by turning a crank attached to an artificial heart?

sithadmin 11y ago
Seems like it could be, given proper controls to ensure relatively regular pumping action (gearbox?). Pneumatic systems could probably be operated with a bellows of sorts.
- ethbro 11y ago
  ... I think I just read the beginning of the best steampunk story ever.
vacri 11y ago
One of the problems for this is then how do you mount the heart? The human body isn't great for hardpoints. Yes, you can screw in stiffening devices, but for something that is meant to move, it gets a lot harder. Cranking a box requires that the box be locked in place, or it will move with the crank. The 'heartbox' in such a case can't be easily attached to ribs, as these move relative to each other, or to the spine. And that's the end of hardpoints in the chest. You might be able to put the pump somewhere else (pelvis?) but now you're affecting other organs as well. On top of all this, skeletal muscle tires quickly. A pump bulb arrangement might be better than a crank, but it's still the case that voluntary muscle movement isn't really designed for extended rhythmic use (eg: runners have to train a lot to be able to sustain running for any length of time)

Mz 11y ago

Excerpts: "This doesn’t only take from your body, it takes from your mind, spirit, and soul," De La Cruz says. And: Perhaps the biggest moral conundrum, though, has nothing to do with living with a mechanical heart, but dying with one. Unlike biological hearts, artificial ones can pump blood throughout the body and oxygen to the brain when the rest of the body breaks down. Death is dragged out — and may require the machine be shut off. "I’ve had patients where the liver and kidney failed, the skin turned yellow and died, and the only thing working normally was the brain," Arabia says. I find stuff like this incredibly disturbing. I always find myself wondering why doctors don't spend more time on helping people keep their own organs functioning instead of on this kind of stuff. I find this very scary. "Resistance is futile. You will be assimilated."...because we are only going to offer you something Frankensteinian like this and not offer better options for healing the tissues you were born with. I have a condition that accounts for a high percentage of lung transplants. So this stuff hits rather close to home for me.

oldmanjay 11y ago
> I always find myself wondering why doctors don't spend more time on helping people keep their own organs functioning instead of on this kind of stuff They almost certainly do. It's a pure anecdote, of course, but I've had doctors in many states throughout the US and to a one, they communicate information intended to help me maintain better health as a preventative measure. If you mean that doctors should spend effort on better treatments for failing organs, there are a number of projects working in those directions right now. Basically, I'm not sure what is disturbing you.
- Mz 11y ago
  Basically, I'm not sure what is disturbing you. I hesitated to reply to you at all. You kind of waved off my concerns and didn't really ask a question. So I am concerned that replying is a mistake. But I seem to be damned no matter what I do when it comes to topics like this. I mean, why did you reply? The manner in which you replied seems pretty dismissive, given that I closed with a statement that I have a condition where transplants are common. But assuming you answered in good faith and just honestly don't see how bad your reply could sound to me, here is what disturbs me: If you have certain conditions, doctors don't really try to help you maintain better health. They chalk up bad outcomes to your official diagnosis and kind of wash their hands of trying harder. Then heroic interventions, like transplants, get all kinds of glowing press. When you get listed for transplant, you basically sit around waiting for someone relatively young and healthy to die tragically in an accident so you can have a second shot at life. I can't imagine the toll that takes on your psyche. That isn't a criticism of patients who accept the only option they are really being offered. But I think we can do better than that, and real quality of life is being given short shrift as medical professionals zealously pursue the "Ooh, shiny!" options that will get them impressive headlines. I also understand the pressures on them which lead to that, but it is the patients who suffer horribly because of it. It just makes me think something is very, very broken. And no one cares to even discuss that, much less try to fix it.

brc 11y ago

The article only briefly mentions it, but the future looks like pulse less continuous flow hearts. This one http://bivacor.com http://bivacor.com uses magnetic levitation to eliminate wear surfaces and needs no external air pump like the ones in the article.

esturk 11y ago
I'd heard about this a few years back but there's been no progress since about any clinical trials. Since the articles mentions SynCardia as the only artificial heart company approved by the FDA, I'm guessing the BiVACOR is still not ready?