Wonder how the join the arteries to it. Any pressure seems likely to kill biological tissue, and while it might grow on, presumably that would take a while. Maybe some kind of glue?
They have what they call sewing cuffs attached to short arterial and venous grafts which you can get already for surgical repair of blood vessels. The sewing cuffs are essentially little cuffs made from polyester velour and silicone and then the surgeon sews through the flanges on the cuffs to anastomose to the blood vessels.
Here is a paper that talks about it for LVADs, which are similar but different
The BiVACOR titanium artificial heart is sutured to the arteries, not glued. Surgeons use biocompatible synthetic graft materials (like Dacron or ePTFE) to connect the arteries to the device.
Sometimes they use bioglue to cover up mistakes in their sewing, they're not supposed to, and you certainly can't do things like put bioglue all around the circumference, but my understanding is that it's used for touch up here and there.
That’s interesting, thank you for the gentle correction and illuminating that caveat. I just shouldn’t make assertions about topics I have no background with when I know I just read about this on Google Scholar right before commenting. I’m basically confidently faking it like ChatGPT.
“ah they stitch it to this neat synthetic graft stuff therefore glue couldn’t/wouldn’t be used”: wrong.
>I’m basically confidently faking it like ChatGPT.
No, this is different. You're reading a scholarly source and regurgitating it without knowing some of the tiny details or exceptions that would only be common knowledge to an actual practitioner in the field.
ChatGPT would be making up completely different things, such as claiming the artificial hearts use subspace fields to work.
ChatGPT says pretty much exactly what the parent comment said, because they both used pretty much exactly the same workflow to generate responses. Both are pulling from scholarly sources (and shared experience such as their knowledge of language) and synthesizing an answer. Neither are experts in the field.
Ironically, the main source of misinformation in this thread appears to be you.
I've read a number of reports about that. Apparently it's a little unnerving at first, but the biggest problem is that they have to make sure that any medical professionals or people they know are aware that they don't have a heartbeat and that's expected and does not mean they need CPR.
Also, there's a long-term question of whether there are any processes within the body are keyed off of the heartbeat, because biological designs are often spaghetti and take full advantage of any random interaction and make it load-bearing.
I have a heart abnormality that shows up as an inverted T-wave on an echo cardiogram. Some physicians will immediately think I'm having some sort of heart attack, though I display no symptoms. It's actually that my heart fills fully and empties fully in a single cycle. I'm not a medical professional, so all I have are laymans explanations, but what it means is that my heart beats less frequently but stronger than the average heart. It was documented thoroughly throughout my time in the Marines and a cardiologist suggested it wasn't a defect. My heart rate remains much lower than other peoples when under stress and my heart rate at rest is only slightly lower than an average persons. When I asked him what all that meant he suggested that I probably won't die of anything heart related, but my body is otherwise normal.
I would guess that, all things remaining the same, you'll have a life a lot longer than most people. I wonder if that behaviour could be induced in a normal heart, as it looks like it's a timing thing.
My guess was the opposite, that it would lead to scarring and eventual heart failure. Many top athletes end up with scarring on their heart from chronically working it so hard. My completely uneducated guess would be that the single power pulse would be a constant source of high impulse strain on the heart muscle, compared to two lower power pulses.
If you don't mind me asking, what is your blood pressure with this abnormality? My gut feeling would be that it you have a much larger gap between your systolic and diastolic numbers than average?
> Also, there's a long-term question of whether there are any processes within the body are keyed off of the heartbeat, because biological designs are often spaghetti and take full advantage of any random interaction and make it load-bearing.
I've heard it suggested that musicians keep time according to their heartbeat; I don't feel like I'm doing that when I'm playing music, but I'd be interested to see what a musician feels like after having this procedure.
The regulation of any individual process in the body is a rube goldbergian nightmare of hormones and neurotransmitters and things that just happen to fire under the right conditions.
I have absolutely no doubt that something in the body relies on a periodic heartbeat in some fashion, but it seems so far to not be anything particularly critical.
Agreed. Hell, it wouldn't surprise me if some part of human neurology used heartbeat as a clock signal (particularly aspects that would benefit from speeding up in same situations the heart does).
>The regulation of any individual process in the body is a rube goldbergian nightmare of hormones and neurotransmitters and things that just happen to fire under the right conditions.
Yeah, it makes me wonder if would be possible to re-engineer some of this stuff to reduce the needless complexity and improve performance and reliability and service life. The problem is that there's so much spaghetti code that any change you make could have unintended consequences.
I mean, with that level of heart failure that an artificial heart is required, there are a bunch of other medical concerns that should be reliably transmitted. As an example, people with diabetes might have tattoos.
Also, CPR is administered primarily when breathing is not sensed. If the patient is already in the hospital, they will surely check basic stuff, like a huge scar on the chest.
Though it would be very interesting if the machine would artificially output a potential vector that makes it very apparent to EKG and similar devices that it is operating, but it is not an ordinary heart (e.g. doing a square wave). It would require minuscule energy.
> Such a pump has no valves, so a patient using the Bivacor heart in its most basic mode would have no pulse. But we recently adapted our device to give it a pulsatile outflow option.
> The pump can run at constant speed, producing continuous blood flow at a constant pressure, and in our early experiments we concentrated on testing this “pulseless” mode. But it’s easy to change its speed, and our later experiments proved that controlled speed changes could produce a wide range of flow and pressure characteristics. Running the pump first at high speed (sending out more blood) and then at low speed (sending out less) creates something resembling a biological heart’s pulse; rapidly alternating these two speeds creates something that looks like a normal heartbeat.
> We’re now working primarily in that pulsatile mode. Within cardiology, there’s an open debate about whether a pulse is necessary for good health… [0]
The ieee.org article has significantly more detail and is a fascinating read.
The lack of pulsatile flow is associated with formation of AV malformations in the colon which can cause GI bleeding which is a more than a little problem when you have a piece of hardware in your chest which requires you take anticoagulants.
As I've understood it, not having a pulse creates all kinds of problems, blood clots and whatnot. It's simply not good for the blood, nor the blood flow. The body isn't made for it.
Pulsatile flow doesn't have such issues, so a Swedish company called Real Heart is making a TAH that pulses like a heart.
So far they've done successful tests with sheep and tons of testing of various blood parameters which look way better than traditional continuous-flow TAHs. Clinical trials on humans should be coming up relatively soon.
I hope they make it, and can improve it and make it smaller to fit children etc. It's pretty interesting technology.
Here's a video where Bivacor is working on making their impeller design simulate a pulse: https://youtu.be/3uV8XZcIBbk?si=I9Gf6pEd9v71Q7JJ. Also has nice interview with the inventor/founder Daniel Timms where he talks about the motivation for doing this companany i.e. when his dad got heart failure.
I’m sure it does cause some problems as the human body is very intricate, but in the capillaries blood flow is often approximated as a steady flow in medical science.
Even more spooky that if they died from, for example, a gunshot wound then their heart would continue to beat. apparently this is a serious issue for coroners when declaring death.m
> the titanium heart is only meant to keep a patient alive while they wait for a heart transplant, which has always been the goal of fully mechanical heart development at this stage of the game.
From the outside, it looks like a race between figuring out the biocompatibility and power issues for total artificial hearts vs. figuring out the immunological issues for xenografts (pig hearts, mostly).
If I had to put money on it, I’d bet that the xenografts win. It doesn’t seem like we’ve made huge strides toward solving the power and durability requirements of total artificial hearts, while immunology advances are happening rapidly. Exciting times, nonetheless.
Would be nice if a pig didn’t have to die to save a human though. This is not something everyone cares about but some people (like me) do care. Hopefully some day we can advance the technology enough with artificial solutions.
This is honestly a pretty niche concern. Even most religions that strictly forbid eating pork make an exception if a human’s life is at stake.
Your best bet would probably be in advocating for the pigs to be engineered to prevent cortical development, ensuring they don’t become anything beyond twitching, unconscious organ bags. In many ways I think people would find this more disturbing, though.
My sincerest hope is that eating animals becomes less popular over the next hundred years such that killing them for medical needs becomes less acceptable.
I’m an atheist and do have concern for the slaughters that are done on behalf on my own life and consumptions. Removing (99%) of consumptions was easy. If a pig heart give me a significant portion of life (+20y) I would maybe take the pig life but not for less. An artificial heart would surely remove the moral dilemma. Despite you good faith, a zombie pig would make it worse.
> That sounds high. Are we talking about India here?
It sounds high even for India. About 40% of Indians are vegetarian, a third if we exclude those who eat eggs [1]. The part of the country where vegetarianism is most rampant, the North, is also the highest dairy-consuming part of the country [2].
In any case, while medical veganism is something to think about, it's not worth prioritising until after we have reliable artificial organs.
>About 40% of Indians are vegetarian, a third if we exclude those who eat eggs
Which you should not, since eating eggs does not make a person a non-vegetarian. The only thing that makes a person a vegetarian is not eating animal flesh. Eggs and dairy are fair game; it's only vegans who push it farther and forbid those. This is basic stuff; has someone been trying to redefine "vegetarianism" recently?
AIUI “vegetarian” in India usually excludes eggs. This likely means that a _majority_ of the world’s vegetarians do not eat eggs.
> This is basic stuff; has someone been trying to redefine "vegetarianism" recently?
Oddly enough, when the word was introduced to popular use in English (though note that similar _concepts_ predated it), it usually meant something closer to what ‘vegan’ does today. The current use of the word is a 20th century thing. Words get redefined, all the time; that’s how languages work. Deal with it. In this case, the word has generally tended to be defined in _more_ permissive terms, not less.
It kind of feels like activists have been trying to erase the concept of vegetarianism/pescatarianism in recent years while pushing full-on veganism.
That's probably not a good move if we want to achieve a pragmatic reduction in meat consumption to help reduce related CO2 emissions. A smaller step is a much easier sell.
tbh I bet plenty of bacon lovers feel bad that a sweet intelligent animal dies to make their meal, and if a perfect copy of bacon could be made without it I bet a good number of them would be happy to switch to it.
This does seem like a more "palatable" alternative and there should be excellent opportunity for the lab-grown pork to have a place on the table. Would seem less cruel to a lot of people I would think.
This bacon lover has seen how pigs are treated in industrial facilities and has lost all appetite. I rarely buy it, from a local place whose pigs are slaughtered not by low wage people in a dark slaughterhouse that must meet quotas and have very disturbing ideas of fun.
I was raised as a pork lover but did stop as a teenager on my own a couple years before I quit beef. I think that did have a positive effect on my young health in the interim, but eventually everything was replaced by more comprehensive plant-based alternatives.
We've been aiming higher explicitly for at 70+ years (https://en.wikipedia.org/wiki/Artificial_heart). I've been following it for 50. Artificial hearts were 5 years away since at least 1972 or so when I first learned about this field. The problems (mechanical, surgical, electrical, biological) are endless and it's an astoundingly hostile environment for machinery. We have enough problems getting pacemakers to work without severe problems.
Because our goal is aligned with our actual problem (survival of individual human beings), as opposed to the merely partially-aligned goal of "statistical survival up to reproduction age"? Natural evolution is an unaligned AI, in a sense: powerful, but not helpful.
Eventually humanity will defeat this problem, and we won't even need computational parity with natural evolution to do that. Most of that computation is wasted.
It's really easy to come up with a better plan than evolution for lots of things.
If our bodies were peak, we wouldn't need to use hundred(s) of hours of exercise per year to force muscular and cardiovascular improvements, it would just happen. Muscles wouldn't shrink away in an aggressive attempt to conserve calories, especially not regardless of BMI.
If our bodies were peak, we wouldn't need to use hundred(s) of hours of exercise per year to force muscular and cardiovascular improvements, it would just happen.
Then what would be the point of living if you had nothing to do but wait for updates? How boring.
Even a self-improving machine is spending time, not exercising but “designing a better version of itself”. Which is an “exercise”.
I hate to say this but I think your comment misunderstands the beauty of life and the challenge behind the struggle to improve. It is a blessed journey.
I personally think being fallable and not having full control of my destiny, while scary, is a feature and not a bug. It seems to make existence exciting.
“Nothing to do” is not the same as not having to exercise. Exercise is quite boring, and you’d have more time to appreciate the beautiful things if you didn’t have to do it for maintenance.
It's boring "for you" that is your opinion, I absolutely love hiking, weight training, football and surfing. I am a physical person. If you find it boring, that's your own preference.
You're arguing against a strawman. I'm not complaining about working for self-improvement, I'm complaining about how muscles shrink away so rapidly when not in use. Look at what happens when people are bedridden for a few weeks, that is not good design!
And I'm not saying people should automatically look like body builders, I'm saying the baseline should be a healthy level.
Each of your muscle fibres contain what is known as myonuclei. These are a structure within the muscle cell that act as the ‘brain’ of the cell – in this manner, they are what tells the muscle fibre to grow in response to strength training.
Interestingly, when you undergo a period of strength training, you see an increase in the number of myonuclei within your muscle fibres.
I had a child, took a year off lifting, or basically doing anything but walking, I didn't lose much mass or strength and it hasn't taken me long to get back where I was, I'm pretty happy with the current design, maybe you should train more so you actually have some muscle in case you do need to spend a few weeks in bed?
I'm pro genetic modifications for these sort of (slight) changes. We live in entirely different environments and our baselines to be healthy makes sense to me. Of course the next step always seems to be "make superhuman soldiers" or "designer babies".
I mean, no, the human heart is absolutely not “peak technology”, not even peak of what is possible in nature (birds have us beaten), but none of these hold a candle to, say, a turbine.
The main issue here is the combination of biological tissue/conditions and artificial ones without either giving out.
You can do plenty of other things good for your heart that is much less damaging to the rest of the body. Running is horrible for joints. Just walking at a brisk pace will get the heart pumping. If we want people to get more active, there are much better things to suggest that go for a run. I ran long distance all through school, and refuse to run for running's sake. Playing soccer is the only running I will do, but at least there's a purpose. Walking, swimming, riding a bike, spin class, whatever are much easier suggestions for couch potatoes to start with
I always wonder about survivorship bias in studies correlating exercise and health. Someone with joint trouble isn't able to run much, for example. It filters those people out. No doubt there are real benefits, but simple correlation will always have that problem.
tell that to my knees and ankles. the equipment is much better today than it was back when Moses and I were kids, but there are plenty of other ways of getting people active than jumping straight to running.
How is running bad for our joints? Maybe if you do it on concrete in a bad shoe, but the human body was literally made to run - which is very apparent from its design (our thighs are basically a spring that can “charge up” slowly in the “up” phase of running for less energy usage + no hair and improved thermodynamics (people can literally run for longer distances than most other animals with very few exceptions)), and you can even feel it yourself, like no other sport has such a short getting up to speed phase. If you start running for a week, you will already feel a huge improvement, unlike in tennis or bodybuilding where it might take months to noticeably get better.
prior to 2020, one of the perks a lot this audience had with their job was in office gyms. for the price of a decent pair of running shoes, you could afford a few months of a gym membership. you could also do jumping jacks, or any other number of at cardio exercises from plenty of places with Apple's offering just an example. i would venture a guess there are youtube channels for it as well. to say that exercise is cost prohibitive is just someone looking for excuses.
Same reason as why we're not developing starships to go to the other side of the Milky way at the moment: We don't know how to and the leap from "what we can do right now" (ie we struggle to get people to the moon permanently) and "other side of the galaxy" is simply too big.
That white hose you see coming off the back of it is the drive line which passes out the chest and connects to an external battery. It's not a normal life with one of these in place, a heart transplant would be vastly preferable.
I know people who worked on that, I've held one in my hand.
It was not designed with long term implantation in mind.
It was designed to get funding and keep the company alive. The device itself was very crude, not statenof the art at the time, and much of it was hand dip-molded with basic materials. It was a hand made research device that in all reality would have never been expected to be reliable and long lasting.
The Bivacor, Heartmate III, these things are in a different class.
Passively-stable magnetic levitation is possible with diamagnetic materials (notably including superconductors), but those probably don't meet the requirements of this project.
- "This positional control system works as follows: Tiny contactless sensors send out magnetic fields that interact with the rotor, determining its exact location many times per second. If the rotor is moving in one direction or another, the control system puts electrical energy into electromagnetic coils within several actuators, causing them to cancel out that movement."
I know these aren't intended for long-term use, and presumably not in ambulatory patients, but still, this passage gave me a tremendous amount of range anxiety:
> Patients will wear a 4-kg external controller pack that contains two rechargeable batteries (providing about 5 hours of operation each), although they can also plug in directly to a power outlet.
Like, the stress of finding a free outlet when I'm on 7% charge is already bad for my heart
This writeup is significantly better than the OP link. Should probably be the article of record.
The section on constant flow vs. variable flow to simulate a heartbeat got me thinking about how weird it would feel to have no pulse, or what it’d be like to experience a moment of excitement/adrenaline without the accompanied pounding in my chest.
Exactly. And systems for commercial aircraft are actually designed (by law) to be dual fault tolerant. This means that all safety critical systems on an airliner need to have 3 filly redundant, independent systems and each needs to be able to function without the other two.
In even class III (implantable and safety critical meaning the patient is harmed or killed if they fail) medical devices are only required to be single fault tolerant.
>And systems for commercial aircraft are actually designed (by law) to be dual fault tolerant.
Not true. Proof: Boeing 737MAX MCAS system, which relies on only one sensor, and when that sensor ices up, causes the aircraft to fly into the ground, killing many hundreds of people in two separate incidents. This design was fully approved by the FAA.
Yeah, that's a famous example of a failure in the process.
The deal there was the MCAS system was originally designed such that it was thought to be not safety critical. It relied on another sensor that was also non safety critical in its other uses. But then over time Boeing made changes that made it safety critical, and rather than upgrade the hardware they put some footnotes in the manual and expected pilots to do things to avert disaster, but then they didnt properly train pilots to those changes to their duties.
Perhaps, but there are a pilot and first officer to take over if the autopilot goes out. You better be in the OR if your titanium heart tries to kill you...
The heart is not necessarily the first organ to give out, the blood vessels themselves, non-dividing cells getting filled up with “junk” that won’t get cleaned up, all the space between cells do also to a degree. There never was evolutionary pressure to fix these issues (and there is none today either - people have children before 40, where these types of “faults” are not common yet).
Maybe this is the first time this technology has been used in an artificial heart, but "maglev" pumps are not new --- they've been around for at least a few decades. It's known as "wet rotor bearingless" in existing literature, and they are found in numerous white goods such as dishwashers, washing machines, HVAC systems, as well as aquariums and computer water cooling. Usually the drive electronics are the failure point.
Yeah the novel part of this is the use of this technology in an artificial heart. We use these in the chemical industry for really harsh services such as a chemical that will destroy any uncoated metal or traditional pump seal.
> That being said, the titanium heart is only meant to keep a patient alive while they wait for a heart transplant, which has always been the goal of fully mechanical heart development at this stage of the game.
Why is this? What are the downsides of just keeping this artificial heart forever? Do the components somehow wear out so fast that it makes more sense to have another surgery with a real heart, or is it something with the recharge requirements, or something else?
All heart pumps damage the blood. So far we've not found a way to pump blood without causing damage due to various factors, sheer, pressure, heat, etc.
Impellers are particularly bad. Alternatives that use flexible membranes are better but still not perfect. Abiomed and Ventriflo both had pumps that use a flexible membrane. Abiomed had the first TAH (total artificial heart) to be implanted.
There are also other problems with blood pumps, such as stasis areas where blood can stagnate causing issues like thrombosis. These can be caused by valves or other issues in the flow path.
People on blood pumps need blood thinners and anticoagulants which can cause their own problems long term.
The problem with an artificial heart is that if it dies, you die; a real heart is (I am confident) more reliable and will have more warning signs and partial functionality before quitting. For now anyway, I'm confident that in our lifetime artificial hearts and whatnot will become more reliable.
I hadn't thought of that, that makes sense! I wonder if we can one day have artificial hearts with a built-in warning system for failure. Maybe they could even flag irregularities _before_ total failure and go into some kind of minimum maintenance mode, giving the user time to get to a hospital in (relative?) comfort.
Edit: sorry, I realized you suggested almost this exact thing above; I just got excited and replied too fast.
It’s hard to say for sure; we don’t have enough people doing it.
But just for one… your arteries contain one-way valves and smaller pumps, to keep blood from pooling in your legs, or from failing to reach your head. These aren’t absolutely critical—children don’t die while standing on their heads—but I can’t imagine they’ll work quite as intended without pulses.
You can’t just swap the main pump on a massive hydraulic system for a different design, and not expect something to go wrong.
It must be an interesting sensation to be alive with no pulse. When I am in complete silence, I can hear the blood coming in waves through my inner ear. With a heart like this, that sensation would be gone, as blood would be continuously pumped.
Does this heart speed up/slow down as the demand for blood in the body changes (like heart rate goes up or down)? If not, will people just pass out if they exert themselves more than the blood flow from the artificial heart can support?
From the article it looks like it does not. Indeed it is hard to imagine a mechanism that could safely accommodate such a feature. maybe an external control knob?
One lung could be replaced with an artificial one which would work together with the artificial heart to regulate oxygen autonomously. The artificial lung could have an oxygen storage so one could hold the breath for hours. One step closer to cyborgs.
re: Steady-state pumping - I wonder if we'll discover that the physiology of body has evolved to prefer (at least in the long term) pulsed blood pumping. That the change state from no velocity to high velocity has some beneficial scavenging effect on the arterial walls or something.
So this is actually something I've worked on for 3ish years. Not this project but a similar BiVAD. Pictured is a dual centrifugal pump. The actual impeller is probably 20mm in diameter. The maglev/ pump portion is most likely a slice motor topology. Which is passively stable axially.
ah. was confused by the timestamping on my end (i.e. 41080654 shows just '2 hours ago' and 41086952 shows '7 hours ago'). must be some other inner-workings. but thanks for pointing out IDs to me for future reference.
this was not intended as a dig - the gradual progression towards "cyborg" via artificial spare parts minor and major is amazing to watch. From ceramic teeth to titanium hips... to entire hearts
