16 January 2017

Self-winding pacemaker

Doctors from Switzerland have created an autonomous pacemaker

marks, Geektimes

A number of models of mechanical watches are equipped with an automatic winding mechanism. This is a very convenient technology for watch owners, which allows you to forget about the need to wind your chronometers once a day or so. The technology itself is far from new – it is about 250 years old. As it turned out, the principle of self–winding can be used when creating pacemakers (pacemakers) - in this case they become completely autonomous, an external energy source is not needed.

Developers from the Bern University Hospital in Switzerland were able to create a technology that allows a pacemaker to receive energy generated by pulsations of the heart muscle. According to experts, the electricity generated is quite enough to completely abandon the use of an external source of electricity – the pacemaker becomes autonomous. 

In the usual case, cardiac pacemakers are placed next to the pectoral muscle, giving electrical signals to the heart. The main task of a pacemaker is to maintain or impose a heart rate on a patient whose heart is not beating often enough, or there is an electrophysiological disconnection between the atria and ventricles (atrioventricular block). 

In order to supply such a device with electricity, it is equipped with batteries that need to be replaced regularly. This requires additional intrusive intervention. A "self-winding" rhythm driver can remain in the human body for many years without the need for regular operations to remove the stimulator and replace its batteries. The method of obtaining energy developed by scientists can be used in other implantable medical systems that also use batteries. 

So far, the technology has passed only the technical stage of testing, its creators have proved the very possibility of creating an autonomous rhythm driver. In order for the technology to be used in the creation of pacemakers, specialists should conduct a long-term assessment of the impact of such systems on the work of the heart. One of the developers, Andreas Haberlin, claims that liquid will accumulate around the device, while the surrounding areas will, on the contrary, experience a shortage of interstitial fluid. Nevertheless, he is convinced that the human body will be able to cope with this problem on its own, although scars will remain in the place of implantation of the sensor and its "generator". There is also a possibility that the heart tissue at the implant site will shrink slightly worse than the "free" tissues of unused areas. 

Prototype of the mechanism of energy generation during heart pulsation 

Now scientists are going to test the system on animals in order to study the medium- and long-term effect of the autonomous pacemaker on the body of living beings. The results of the work are expected to be received within three years. 

As for the mechanical watches with an auto-winding, they start from the movements of the wrists of the owner. The basis of the mechanism of the automobile plant is the so–called sector - a metal half-disk, the center of gravity of which shifts to the edge. The masters place such a disk on a special support that allows the disk to rotate completely freely in different directions. The support and gears transmit the energy of rotation of the disk to the spring. 

A similar principle is involved in the energy generator for a pacemaker. Here, the vibrations of the heart wall also provide the movement of a special load. With the help of mathematical modeling, scientists have clarified the features of the system and its structural elements. To test the idea, the scientists ordered a watch with a car factory from the company ETA, disassembled them by studying the mechanism itself. After that, they replaced the disk with their own, made of platinum (thanks to this, it can be made smaller in size, but heavier) and added a microgenerator made of quartz watches in order to convert mechanical energy into electrical energy. 

Of course, such a pacemaker cannot work directly, without protective mechanisms. A spare battery is required, which will supply the rhythm driver with energy if something happens to the energy generation mechanism. The scientists presented the results of their work in the article.

There are other ways to generate energy using various systems of the human body. For example, colleagues of this group of scientists, also from Bern, have developed a miniature turbine that generates current when blood moves in blood vessels. There are also developments that make it possible to obtain energy in the inner ear of a person or to collect an "energy harvest" from different organs using piezoelectric materials. 

"There are always alternative ways to achieve an important goal, and I think we all have the same motivation – to replace the batteries in implantable medical devices," Haberlin said.

Portal "Eternal youth" http://vechnayamolodost.ru  16.01.2017

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