Physics merges with Biology to Keep the Heart Beating

by Julia Clark, Anna King, and Taylor Kuter

In today’s world, pacemakers are so commonplace, we hardly give them a second thought. Nearly everyone knows someone whose life depends on this device. Despite a wide variety of pacemaker models, they all have the same basic composition, and consist of the same three core parts: a battery, lead wires, and circuitry (How Pacemakers Are Made). All materials used in these parts are biocompatible, so as to be as non-harmful to the body as possible. These components all must meet a series of specifications. The circuitry of the modern pacemaker, which controls the device’s functions, contains an array of sensors, timers, and voltage regulators to control the heartbeat. All controls are generally externally programmable, allowing doctors to make non-invasive adjustments to the pacemaker’s function, if necessary. The lead wires of the device provide the physical stimulation to the heart. Leads are generally thin, insulated electrical wires with exposed ends directly attached to vital points on the heart. Many modern leads are of a “screw-in” variety, securing them to the heart in much the same way as a common screw. The wires are subjected to constant movement caused by the heart’s continuous beating, and therefore must be resistant to fracture. The battery, which powers the pacemaker, must be able to supply 5 volts of power, which is slightly more than what the heart requires for stimulation. The battery must be able to last for a minimum of four years, and must have a predictable life cycle, making it easy for the doctor to know when a replacement battery is necessary. The battery is integral to the pacemaker’s function, and must be replaced after a certain amount of time, depending on the patient. Currently, the only way of replacing the battery is through an invasive surgical procedure.

The need to undergo an operation every ten years in order to replace a pacemaker demonstrates the need for a new design of the pacemaker and how the pacemaker obtains energy. Instead of being run solely on batteries that need to be replaced, we have designed a Hematologic-Electric Pacemaker with batteries that have a back-up power supply that obtains its energy from the natural movement of blood in the patient. The purpose of our device is not to be the power source of the pacemaker but to produce enough energy from the additive that it will charge the batteries of the pacemaker. The capability of having a device that will produce the energy needed to charge the batteries of the pacemaker will eliminate the need for the replacement surgeries of pacemakers.

Our Hematologic-Electric Pacemaker will have the modern pacemaker itself and an additive that is connected by bio-compatible wire that the electrical current will run through. The additive is where the energy is created by the movement of the blood. The location in which the additive will be placed will be a vein. A section of the vein will be cut and our device added in place of the vein with skin grafts to connect the vein to the ends of the device. Stints may be needed in the vein to help support the added weight from the device. We chose the location for the device to be a vein as the pressure within the vein is low but the volume is high (Desai).

Original artwork provided by authors.

Original artwork provided by authors.

The device itself is made up of three chambers. The first inner chamber is in a shape of a barrel. Inside this barrel are propellers which are in the shape of airplane propellers. They are as if two flat surfaces lying horizontally are slightly twisted. The front propeller is made out of a harder bio-compatible material while the back propeller is made out of a more flexible material to create less turbulence in the blood as it re-enters the actual vein. As the blood from the vein travels through the barrel, the movement of the blood causes the propeller blades to spin. The shape of the propellers makes it so the blood can pass through the device freely without a large obstruction in its path. The propellers are connected to the barrel. The barrel is a magnet in which the top half of the barrel has a positive charge and the bottom half of the barrel has a negative charge. Since the propellers are connected to the barrel, the whole barrel moves as one unit. The barrel itself will be enclosed in a thin, bio-compatible membrane. Tightly wrapped around the membrane will be copper wire. To protect the body from exposed wire, the third bio-compatible casing will enclose the wire.
Our design allows the processes of electromagnetism and hematologic-electricity to occur. Electricity is “simply moving electrons” and “some metals, like copper, have electrons that are loosely held; they are easily pushed from their levels” (Intermediate Energy Infobook). The way in which our device creates electricity is similar to the turbine generators today but instead of using a substance like water to spin the turbine, the Hematologic-Electric Pacemaker uses the blood in the vein. The spinning of the barrel, or the spinning of the magnet, causes a magnetic field where the loose electrons in the copper wire, which is wrapped around the membrane of the barrel, are being pushed and pulled by the magnetic field (Intermediate Energy Infobook). The moving electrons in the wire will flow into a connected transmission line which will eventually lead to the pacemaker. There is an AC/DC converter connected to the transmission line just as the moving electrons enter into the line. Since the electrons are rapidly moving back and forth, they are moving in an alternating current. Before the electricity is able to get to the pacemaker, it needs to be transferred into a direct current. The AC/DC converter solves this issue as it converts the alternating current to a direct current so the flow of electrons is in one direction traveling toward the pacemaker.

Photo credit: Web 1/12/2012 via Creative Commons license

Photo credit: Web 1/12/2012 via Creative Commons license

Once the blood is about the leave the barrel, the spinning motion of the propellers will cause the blood to leave the barrel twisting. In order to straighten out and slow down the blood flow, the membrane and the outer casing of the device is extended after the barrel. This extension of casing is called the turbulence reducing chamber. The turbulence reducing chamber solves the problem of the blood having turbulence as it leaves the device, as it allows the blood to regulate itself before it enters into the normal vein again. Inside the turbulence reducing chamber are backflow prevention valves. These valves are in place because as the blood pulses through the vein, there is an inevitable backward suction of the blood that occurs, and the backflow prevention valves make sure the blood will not re-enter into the barrel. Once the blood straightens back out inside the turbulence reducing chamber, it re-enters the actual vein.

“There are about 3 million people worldwide with pacemakers, and each year 600,000 pacemakers are implanted” (Wood, Mark A. and Kenneth A. Ellenbogen). The duration of pacemaker batteries is about 10 years, so every 10 years pacemaker patients have to undergo another surgery to replace the batteries. Our goal is to eliminate the need for replacement surgeries for the batteries of the pacemaker by our Hematologic-Electric Pacemaker.

References

 Ashesh, Sheetal, Pratik, and Deeba. “History of Pacemakers.” The Physics of a Pacemaker. N.p., n.d. Web. 16 Nov. 2012.

“Benefits and Risks- Pacemakers.” Medtronic. N.p., 22 Sept. 2010. Web. 16 Nov. 2012.

“Benefits of the Advances in Cardiac Pacemaker Technology.” National Center for Biotechnology Information. U.S. National Library of Medicine. 15 Nov. 2012.

Desai, Rishi, M.D. “Arteries vs. Veins – What’s the Difference?” Blood Vessel Diseases. Khan Academy, 2012. Web. 11 Nov. 2012.

Heart Rhythm Society. “Treatment and Devices.” Treatment and Devices. Arrythmia.org, 2011. Web. 07 Dec. 2012.

“How Pacemakers Are Made.” How Products Are Made. 15 Nov. 2012.

Intermediate Energy Infobook. Electricity. Manassas: The NEED Project, 2012. PDF.

Laursen, Lucas. “Swiss Scientists Design a Turbine to Fit in Human Arteries.” IEEE Spectrum. IEEE Spectrum, 16 May 2011. Web. 26 Nov. 2012.

Mittal, Tarun. Pacemakers — A Journey through the Years. New Delhi: All India Institute of Medical Sciences, 10 Sept. 2005. PDF.

Rhoads, Caroline S., and John M. Miller MD. “What are some Recent Advances in Pacemaker Technology?” EMedicineHealth. 18 June 2009. Healthwise Staff. 15 Nov. 2012.

Webster, Andrew. “Scientists Create Blood Powered Turbine To Power Pacemakers.” PCMAG. Gizmodo, 17 May 2011. Web. 16 Nov. 2012.

“Who Invented the Pacemaker?” Rocket City Space Pioneers. N.p., n.d. Web. 15 Nov. 2012.

Wood, Mark A., M.D., and Kenneth A. Ellenbogen, M.D. “Cardiac Pacemakers From the Patient’s Perspective.” AHA Journals. The American Heart Association, 2012. Web. 11 Dec. 2012.

Zax, David. “A Heartbeat-Powered Pacemaker.” MIT Technology Review. 7 Nov. 2012. 16 Nov. 2012.

Quantized Magazine. All Rights Reserved.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s