bring that beat back

Man with no pulse considered a medical breakthrough
Dr. Renzo Cecere implanted the "Heartmate II" mechanical heart into Gerard Langevin in an three-hour operation Nov. 23. The device, which is about the size of a flashlight battery, could last up to 10 years.

The new mechanical heart, which is powered by batteries located in pouches on Mr. Langevin's body, provides a continuous flow of blood so the patient has no pulse. "Mr. Langevin happens to be the only individual currently living in Canada without a pulse and without a measurable blood pressure," Dr. Cecere said Wednesday.

Previously, previously.

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28 Responses:

  1. jkonrath says:

    The Jarvik 2000 is similar - I'm not sure what's different about the Heartmate II, except maybe that it was maybe the first done in Canada.

    They started testing the Jarvik 2000 on humans about six or seven years ago. The big advantage is you can stay on the transplant list and have keep your old busted heart intact, so it can be swapped later. With the old Jarvik-7, they had to carve out your old heart, and there was no going back.

    • gryazi says:

      Yeah, both are "ventricular assist devices." [Heartmate II product page.]

      I caught something on PBS about the development of them a while back, and it seems there were a couple problems with the early attempts at continuous-flow designs. First, doing the obvious thing with a plain impeller winds up shredding blood cells, so some thought had to go into that. Once past that hurdle, it turns out the pulse plays an important role in regulating the growth and organization of vascular tissue. (Best I can find is this abstract, which implies the phenomenon -- high pulse pressure caused overgrowth that blood pressure meds reversed. IIRC, going pulseless causes the opposite problem, leading to thin and lumpy? walls.)

      So... having done the R&D to produce a 'heart' that was compact but would kill you eventually, they needed a plan B, and the assist pump (or at least the continuous version thereof) was born. From this it was discovered that if you don't go around chopping out people's hearts they can often recover, at least to the point of introducing enough fluctuation in pulse to prevent the arteries from going haywire.

      Jarvik has a snarky footnote about a lack of pulse-preservation with competing products, but I can't tell if that really holds water, especially since earlier VADs have been pulsatile and the new continuous ones all seem to bolt on in a similar way.

      I can't find anything very detailed about Mr. Langevin's condition, but it sounds like fairly standard heart failure, which is to say that he still had nearly enough of a pulse to keep him alive between heart attacks. I'd wager that you currently can't feel his natural pulse, but that the doctors wouldn't have put this style of device in him if they didn't expect him to maintain or recover some semblence of one within a reasonable period of time.


      Also, I think Medgadget is going to become part of my daily reading now. Behold, uh, this.

  2. omni_ferret says:

    "Mr. Langevin happens to be the only individual currently living in Canada without a pulse and without a measurable blood pressure," Dr. Cecere said Wednesday.

    I was going to ask about vampires & zombies, but then I realized that they're undead, not living, like he said.

  3. nyankolove says:

    Makes me wonder what happened to the guy who got the Heartmate I.

  4. rapier1 says:

    Hurm. He'd still have a blood pressure. Just not the diastolic portion thereof. I always kind of wondered how they'd tune that... do you make the BP match the systolic or diastolic? I also kind of wonder what life would be like without ever having your blood pressure change. Probably better than being dead.

    • lars_larsen says:

      Well, you couldnt measure blood pressure because you couldnt listen with a stethoscope for the pulse, nor could you palpate it.

      • rapier1 says:

        Sure you could measure it. The automatied cuffs use a oscillimetric technique for establishing blood pressure. Essentially looking for the pulse through variations in the pressure sensor in the cuff itself. In this case you'd just have to look for the pressure differential caused by the expansion of the artery.

        You should also be able to listen for bruits on the brachial artery as the flow just starts up again. It should make a sound distinct from empty and full flow.

        Lastly, you could always use a cannula. But thats a bit excessive.

      • jkonrath says:

        All you need to do is splice in a t-connector and run it to an automotive oil pressure gauge. You'd probably want the electronic type with a sender unit that's right on the t-connector and a wire to the gauge, rather than the mechanical sort with a clear tube of blood running into the back of the gauge.

  5. xthread says:

    Shouldn't the tag on this have been 'Our Zombie Future'?

  6. greatbiggary says:

    Amazing stuff, but what happens when he needs more blood flow? Like say he climbs some stairs, or has some wild Canadian-style sex, whatever that is? Does he just pass out? Can the device tell, and ramp itself up?

    Also, what am I looking at in this pic? Handlebars? Some kind of wind instrument? What kind of awesome flashlight that I wish I had takes such an unwieldy battery?

    • malokai says:

      No, it can't. He maintains one level. Somewhat like what most heart attack victims live with I suspect.

      Picture? Inlet, outlet, connection going to batteries?

      • greatbiggary says:

        The sign will say "No exciting Gerard."

        Also, though you may be right, my money is still on some kind of Kohler / faux Calabash love child.

        • malokai says:

          Other artificial hearts out there have self-controlled flow controllers.. maybe this one will have it too.

          I'm more curious what'll happen to his veins with a constant flow of blood vs a pulsing type of flow.

    • jkonrath says:

      what happens when he needs more blood flow?

      Maybe they could wire in one of those "turbo" buttons, like they had on old PCs.

    • gryazi says:

      Thoratec says the Heartmate II has fixed speed and automatic modes; fixed goes from 6K to 15K RPM at 200 RPM increments, so that's 45 steps. Auto can travel a set range within 8K and 15K RPM, also at 200 RPM increments. Sounds like someone didn't RTFM.

      I haven't read far enough to figure out if the end-user gets to play with any of those adjustments.

      Jarvik says their 2000 has 5 levels ("within a safe range") that the user gets to manually dial in his choice of.

      WorldHeart seems to be implying single-speed, naturally regulated operation on their Levacor, but their other products seem to have some reasonably snazzy automatic controls.

    • jwz says:

      I assume his left nipple has been replaced with a volume knob.

      The ones that go to 11 are classified as munitions.

    • sc00ter says:

      Somebody already commented on how it can change speed.. But regardless I would be more curious if other artificial hearts did the same thing.

      In any event a non-variable-speed artificial heart of any kind is probably better then a non-working real heart any day.

  7. saltdawg says:

    I still subscribe to "that which does not kill me, only makes me stronger"

    Seems all this artificial heart BS proves to make folks weaker.

    Give me a grenade to thow myself upon before I need one of these things.

    (though I'd probably change my tune about an artifical liver...)

    • dachte says:

      Note that not even the most bleeding edge technology enthusiasts are heading out to have this done just for the kicks - it's to help people who would otherwise either be dead or hooked into a stationary machine the rest of their lives. OTOH, I do know some crazy transhumanist types I should tease about this...

      • saltdawg says:

        I'm too inebriated to even know how to process this information.

      • edlang says:

        Could these devices be used to create discrete segments to service various parts of the body? It'd be pretty cool to be able to sustain a perforation in one extremity while the rest of the body continues to function as per normal.

        Also, redundant blood supplies.

        • gryazi says:

          You'd have a hell of a time creating partitions that bound against blood loss and infection but still pass nerves through.

          Then, even assuming some sort of self-regulating gas-exchange gills could be made in a self-regulating package, you've got the problem of fueling the partitioned tissue without inducing diabetic neuropathy/necrosis or starving it to death, and performing dialysis since they'd no longer be plumbed through the kidneys.

          If you're expecting a major 'perforation,' chances are what's left of the appendage is disposable at that point, so you might get by with an 'air bag'-style solution of implanted, automatically-deployed tourniquets at major pressure points. They'd still be a ridiculous bitch to install and maintain, and accidental deployment would have severe consequences, but it could probably be done with our current level of technology if anyone really wanted to.

        • gryazi says:

          Now, returning to this subject, it seems like lining body armor with a powder form of this stuff (or existing equivalents), maybe mixed with some form of anaesthetic, would be a good idea, assuming it'd be soluble enough for the medics by the time you get to them. I don't know if it'd be enough to stop a total gusher, but if the projectile itself blows it through the wound it'd probably give you a bit more time.

          Mixing in a systemic painkiller with a slow onset also seems like a good idea -- if you're injured badly enough, remotely enough, or under fire thick enough that you're still lying there after 40 minutes, you'd probably appreciate something like codeine(?) metabolizing into something active around then; if your buddies have already dragged you off the field, it might spare triage personnel some of the load of distributing initial medication. (I suppose they'd need pocket cards or training on the dose delivered per wound_area ratio, but that wouldn't be too rough.)

          Abuse potential might be a problem with that part, since AFAIK the obvious things that metabolize slowly are active orally... or at least codeine is, which is the only thing I know about. It'd be hard to shoot up something mixed with clotting agent, but if you could just chew on it... [No help that a big surplus of 'discarded' material would appear when taking heavy casualties, when morale might be low.]

  8. rasp_utin says:

    Another good track would have been Alec Empire's "heartbeat that isn't there." Heh.