Heart stimulators, commonly called pacemakers, are small devices implanted in patients to control abnormal heart rhythms. Such cardiac abnormalities are commonly referred to as heart arrhythmias, and pacemakers emit electrical pulses to prompt the heart to beat at a normal pace to prevent those irregular heartbeats.
The number of these life-saving devices that are implanted each year extends into the millions worldwide. One of the overwhelming issues to overcome with such technology, however, is the limited lifespan of the batteries which power these pacemakers.
Many older implanted devices have batteries that last about seven years. These battery packs, with wire leads connected to the pacemaker nearer to the heart, are implanted and secured in surgical pockets either in a chest, abdomen or some other fleshy area of the body. Repeated surgeries to replace worn out battery packs expose patients to infections and excessive bleeding during the periodic procedures.
Newer devices that are placed directly inside the heart are called leadless devices. These pacemakers send an electrical impulse to the heart whenever it senses that the heartbeat is too slow. These pacemakers do not require insulated wires connected to battery packs placed in the chest or abdomen. They are very small devices, about the size of a pill, and have internal batteries that can last for about 12 years.
These small devices are certainly a technological advance, but they present new issues regarding the dangers of retrieving these devices implanted directly into the heart when the batteries wear out.
For that reason, doctors often leave an old device in the heart muscle while inserting a new device, usually delivered via a catheter threaded through a large vein in the leg up to the heart. The depleted pacemakers, therefore, pile up inside the heart. Due to the small size of these pacemakers, however, the “device trash” is not believed to pose any appreciable danger to the patient.
Despite these tremendous advances in pacemaker technology, however, the bottom line is that pacemakers are limited by the life of their batteries, and patients must be subjected to periodic replacements either of a battery pack or the entire pacemaker that may have an internal battery.
Cutting edge pacemaker technology bypasses the entire dead battery issue with the development of pacemakers that contain no batteries at all. These devices are implanted into the heart like leadless pacemakers, but they contain no internal power source!
So the question is, how do these devices work without an energy source—and more importantly—what does all this have to do with murder?
Let me answer that first question about the technology of these supposedly powerless pacemakers. They are called piezoelectric pacemakers and contain high-performance nanogenerators (ah, a power source). The nanoparticles in these pacemakers create electrical impulses generated from motion in the near vicinity of these devices—a high tech motion detector, if you will.
In most cases, the motion of the last heartbeat of the cardiac muscle stimulates a piezoelectric pacemaker to generate the electric impulse to stimulate the next heartbeat, and so on and so forth. It’s like a good vicious cycle of cause and effect.
Some types of piezoelectric pacemakers even harvest energy from blood pressure variations in the heart’s pump cycle to assure continued regular heartbeats. These “good vibrations” pacemakers basically use the same technology that reproduces sounds picked up by a microphone and sent to a loudspeaker. A simplistic analogy, but basically that’s the idea.
Although these piezoelectric, nanoparticle pacemakers are about ten years away from common use, the technology works flawlessly in animal studies, even those that involve pigs and cows—which are about the size of a human and a human heart.
I was fascinated with these studies when I came across them a couple of years ago in an article I read. That was about the time I needed a specific method to stop the heart of a victim in my Almost Dead murder mystery. Yet, I needed that victim to walk out of the funeral home before anyone realized what was happening.
The real mystery here is not if this technology works as promised. Research shows that it has real potential for becoming common practice within a decade. The real mystery here is how my Detective Rosie Young character figures out how the device stopped working and what caused it to suddenly start up again on a perfectly still “corpse.”
So, these motion-activated pacemakers have everything to do with murder in my murder mystery novel. If you’d like to see just how Detective Rosie Young and her partner Detective Vince Mendez solved the case, check out my murder mystery Almost Dead.
Thoughts? Comments? I’d love to hear them!
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