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A Piezoelectric Pacemaker That Is Powered By Your Heartbeat
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."
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.
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Just to be clear the replacement surgery on a pacemaker is almost always done on an outpatient basis with local anesthetic.
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That's right. It comes with a lifetime guarantee.
More like a usb watchdog that restarts the server if it dies.
the UPS analogy is very wrong
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.
I would imagine it must have a rechargeable battery (I'd say large capacitor, but they tout how small it is), or else it would cease to send a signal if your heart skipped a beat, which kind of defeats the purpose of a pacemaker, I should think?
Anyhow, aren't there other and more reliable methods to generate small amounts of electricity inside the body, considering that the patient's heart is confirmed not to be reliable (or else why implant a pacemaker?). Temperature differentials and chemical reactions to name two.
I am also not a doctor, but why do they put pacemakers of this nature (i.e. the kind that only ticks the heart and can't provide shocks) in the chest? Why not where it can be easily accessed and recharged, e.g. by an induction charger - the same methods we use to charge toothbrushes and some phones - without having to do surgery to change batteries every couple of years?
;>)
Anyway, the key point is that the power needs might be great enough that such a mechano-electric harvester might take too long to store enough "juice" to be able to send out multiple defibrillatory stimuli. But I don't know about many of the numbers or parameters/variables involved in this particular system or other systems like it:
-- how much less power you need to apply directly to the heart as opposed to stimulating with an externally defibrillator applied to the chest wall,
-- I don't know what the efficiency of the piezo-electric system per heartbeat or the amount of current and voltage generated by it per heart-beat,
-- i don't know the efficiency of the electrochemical battery system that could be used with it,
but I'm wondering if it could generate enough power to be useful or not. C'est tout.
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).
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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?
The UPS analogy is wrong indeed. Let's use FedEx instead.
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Heartbeat powered pacemaker is as useful as a solar powered flashlight.
In other words, very useful. The typical flashlight will have a charge time of about 6 hours while providing 8 hours of light. They can penetrate up to 50 meters in the dark, and can be visible up to 2 kilometres. The cell life of the solar energy cells can be as long as 20 years! Exactly what you need in an emergency. Similarly, a heartbeat powered pacemaker can trigger heartbeats (note: trigger, not power. The beat itself is still chemically powered, like all other muscles) for a lifetime.
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