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Biotech Medicine Power Hardware

A Piezoelectric Pacemaker That Is Powered By Your Heartbeat 84

Posted by samzenpus
from the no-batteries-required dept.
MrSeb writes "Engineers at the University of Michigan have created a pacemaker that is powered by the beating of your heart — no batteries required. The technology behind this new infinite-duration pacemaker is piezoelectricity. Piezoelectricity is is literally 'pressure electricity,' and it relates to certain materials that generate tiny amounts of electricity when deformed by an external force — which, in the case of the perpetual pacemaker, the vibrations in your chest as your heart pumps blood around your body. Piezoelectric devices generate very small amounts of power — on the order of tens of milliwatts — but it turns out that pacemakers require very little power. In testing, the researchers' energy harvester generated 10 times the required the power to keep a pacemaker firing. Currently, pacemakers are battery powered — and the battery generally need to be replaced every few years, which requires surgery. According M. Amin Karami, the lead researcher, 'Many of the patients are children who live with pacemakers for many years,' he said. 'You can imagine how many operations they are spared if this new technology is implemented.' This piezoelectric energy harvester is about half the size of a conventional battery, too, which is presumably a good thing."
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A Piezoelectric Pacemaker That Is Powered By Your Heartbeat

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  • No, the device does not violate conservation of energy.

    Anyways, nice technology. I hope this really works; so much awesome technology seems to go out as a puff of vaporware.
    • by Trepidity (597)

      To elaborate, the reason why is basically the same as why a battery-backed UPS charged off mains electricity doesn't violate conservation of energy: it charges off an energy source while that source is still good, in order to use the power in case the energy source cuts off.

      • Re: (Score:3, Informative)

        by msauve (701917)
        No, that's not the reason. A UPS has to be able to replace the full power provided by the main when in use. A pacemaker only needs to provide a small trigger signal, which is much smaller than the output of the heart itself.
        • by bakuun (976228)

          No, that's not the reason. A UPS has to be able to replace the full power provided by the main when in use. A pacemaker only needs to provide a small trigger signal, which is much smaller than the output of the heart itself.

          "... which is much smaller than the output of the heart itself."

          Kind of like a UPS and an electric power plant then, yes?

          • by msauve (701917)
            No. You're confusing inputs and outputs. A server doesn't generate power to charge the UPS.
          • More like a usb watchdog that restarts the server if it dies.

            the UPS analogy is very wrong

            • by nazsco (695026)

              you guy are killing each other over analogies... why not make a car one everyone can agree?

              • by TheLink (130905)
                OK it's like the electronic engine management stuff (ECU etc) that keeps your car engine running well. As long as the car engine runs, it turns the alternator which supplies energy to the electronics and tops up the battery.

                And just like you can restart a car engine using the stored battery charge, in theory you might be able to use this tech to store enough charge to shock the heart to restart it in case it stops (an ICD with a battery that's kept charged by the heartbeat).
            • Re: (Score:3, Funny)

              by ArcadeMan (2766669)

              The UPS analogy is wrong indeed. Let's use FedEx instead.

      • by Anonymous Coward

        Except you aren't capturing electrical energy from your heart. The electrical energy provided by the pacemaker is triggering the heart to make use of energy obtained from nutrients and create kinetic energy. Then it diverts some of that kinetic energy to replace the relatively minor electrical energy that was used to create the signal.

      • by polymeris (902231)

        Seriously? Your comparing this to an UPS the one time a car analogy would actually have made sense?

    • The problem is that it's really great for one set of patients - kids who have had their heart's natural pacemaker disrupted due to abnormalities that arose during development - but not much use in the larger population of patients who need pacemakers (generally elderly adults with bad hearts), because the adults so often get a combined pacemaker/defibrillator. And there's no way it can generate enough power to defibrillate someone.
    • by bondsbw (888959)

      How much harder does it make the heart work?

      If the device uses 5% of power from each heartbeat (and I have no clue what the actual number is), that means the heart needs to beat around 5% harder to have an equal effect. Or, the heart beats the same but the blood only pumps about 95% as hard. That could be taxing over a long period of time on a weaker heart (the kind that tend to need pacemakers).

  • by Anonymous Coward

    That's the first thing I thought of. I'd assume it follows the same basic concept.

  • About that Surgery (Score:5, Interesting)

    by 1967mustangman (883255) on Monday November 05, 2012 @07:51PM (#41888087)
    Just to be clear the replacement surgery on a pacemaker is almost always done on an outpatient basis with local anesthetic.
  • Cool! It can harvest enough energy to at least start the pacemaker signal for the heart cells, but how much standby time would it have in case the heart stops beating for too long? (Remember that rechargeable cells and capacitors slowly decay over time in their charge-keeping ability).

    .

    It's probably not a "defibrillator" type of heart-restarter in case the heart starts fibrillating: defibrillators require too much power in order to be able to "jump start" the heart. (At least I think that's the kind Che

    • by EdZ (755139)
      Defibrillators do not 'jump-start' the heart, they defibrillate (i.e. stop fibrillation [wikipedia.org]). This is often rolled into the function of a pacemaker.
      • even so, the amount of power (voltage \times current) required for defibrillation is quite seriously more than the amount of voltage and current required for the basic sino-atrial node pacemaker replacement which only has to start or pace the cardiac electrical cycle when the pacemaker no longer performs adequately.

        .

        What I questioned was the ability of the piezoelectric energy harvester to cannibalize enough power to be able to do perhaps even one defibrillation attempt. This, of course, depends upon th

        • also, that is why I put the phrase 'jump start' in double quotes as so: "jump start", to indicate that I was making little air-double-quotes around the phrase as I said it, so as to imply "no it's not really jump-starting, it's just resynchronizing the asynchronous non-entrained fibrillation occuring in the myocardiocytes so that once we've jolted them, an entrained signal can propagate in the correct direction and allow the correct temporal propagation of myocardial contractility so as to squeeze the blood
          • It's like using the vibrations of passing four locomotive coal trains to charge the battery that drives the signal lights, and it's a very busy track with a lot of passing large trains but without much signalling going on.
            Just signals to control traffic, no HUGE battery reserve to run a locomotive starter motor.

            So in other words, a pacemaker and not a crashcart defibrilator, and having the constraint that no battery is allowed at all is not reasonable. It could be seen as deliberately adding a constraint
            • I did not "add the constraint that no battery is allowed" (quoting you there). Here's the quote of my GP post (quoting me now): "i don't know the efficiency of the electrochemical battery system that could be used with it,"

              .

              I specifically mentioned electrochemical battery there, and in my original post I mentioned both using a capacitor and/or a rechargeable battery. So whomever you're complaining about adding that constraint, it certainly wasn't me. I got no problems with ze batteries, okay?

              • by dbIII (701233)
                You do seem to be looking for kilowatts instead of microwatts though, and a crash cart defibrilator instead of a pacemaker, which can do the same job with a lot more finesse and vastly less current (it's right where it's needed already under the skin and can get the timing right). A constraint of having a battery that could supply what looks like kilowatts from your description is what I was referring to. Early pacemakers were like that but that was probably before both of us were born.
                • Nope, not looking for kilowatts. Look up implanted cardioversion devices, which are implanted pacemakers with defibrillators circuits built in and fibrillation detectors and algorithms built in along with pacing ability.
                  • by dbIII (701233)
                    Um, haven't you noticed yet that you are getting things wrong and others know a little bit about the subject? If you followed your advice and looked things up you'd find the power requirements are very low (battery life in years). The big deal here is never having to do anything invasive to replace a battery once the device is fitted.
  • So when my heart skips a beat, it will actually skip quite a few? Sounds great, screw testing. Wire me up!
  • As long as your heart keeps beating... your heart will keep beating?
  • Back in 1989 when I was doing my masters one of my classmates had this as her project. No hardware, just some conceptual studies, literature survey and a project report.
  • by Anonymous Coward

    I don't know if straight pacemakers are all that common. My late wife had a pacemaker that was also a defribulater that gives quite a jolt if the heart tries to stop beating. Even thirty minutes after death that thing was still firing away in her chest.

    • by gmhowell (26755)

      I investigated the issue back in September. IIRC, about 1/3 of all pacemakers in the US include a defibrillator function.

  • Sounds kinda optimistic to me.
  • Will this allow for enough power to encrypt the wireless connection these things have?
  • Sounds to me like another cog in the wheels of the zombie apocalypse.

Prediction is very difficult, especially of the future. - Niels Bohr

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