Students Use 3D Printed Heart to Develop Next-Generation Pacemaker

Several million people rely on pacemakers to regulate their heartbeats. There are different types of pacemakers, although for years the status quo has been a pulse generator that is located in a patient’s chest and connected to the heart via one to three wired stimulus and sensing leads. But recently new options have been appearing on the market – wireless and leadless options that are simpler and less vulnerable to complications. One of these wireless designs was recently presented by a team of students at Rice University, and won the Excellence in Capstone Engineering Design Award and a $1,000 prize at the annual George R. Brown Engineering Design Showcase on April 12th.

The Love and Pace team designed a pacemaker that would place a network of chips, each the size of a grain of rice, in multiple places inside the heart. These chips would communicate with a base station located under the patient’s skin and would charge via radio frequency. Whenever the base station sensed a problem with the heart’s rhythm, it would trigger the embedded chips to release a jolt of energy that would re-establish the heart’s normal rhythm.

Last year, former Rice University faculty member Aydin Babakhani and colleagues at the Texas Medical Center introduced a concept for a more advanced wireless pacemaker that could be embedded in the heart and charged via radio frequency energy harvesting. The students are attempting to build on that technology by establishing an entire network inside the heart.

“The current (commercial) leadless solution is a bullet-sized pacemaker with a battery that is installed inside the heart,” said team member Yoseph Maguire. “It is effective only in pacing a single chamber of the heart.”

Maguire and his fellow team members, computer and electrical engineering students Chris Chivetta, Yixin Chen, Cody Tapscott, Ricky Chen and June Chen, came up with a concept that uses millimeter-scale chips embedded permanently in the heart. They demonstrated the system using a 3D printed heart with light traces triggered by programmed anomalies and sensor-simulator chips that detected the problems and sent data to the base station. The base station then commanded the stimulators to released timed jolts to adjust the heart’s rhythm.

As no wires are involved, the control unit continuously sends power to and gathers data from the embedded chips through radio frequency identification. The chips would deliver 25 nanojoule charges to stimulate heart muscles.

[Photo: Brandon Martin/Rice University]

“It’s a master-slave network,” Maguire said. “Once you have these chips positioned within the heart and covered over by scar tissue, they would communicate with the aggregator — a bigger board that has an RFID reader, takes in all the data, processes it and relays it back to the chips. If things aren’t working out well in the heart, the aggregator would say, ‘Hey, guys, I need you to pace.’ They would continuously pace until the aggregator observed that things are good in all the chambers.”

The project is far from being finished, and will likely be carried on by subsequent teams of students after these students graduate. When Rice University mentors find that a project is too complex to be completed in one year but is important enough to continue researching, they will pass it on to another set of students.

“The heart is a very unique and harsh environment for circuitry,” Maguire said. “Having it all integrated is a huge research task, so for us, just developing a proof-of-concept is enough.”

The team developed its ideas with help from faculty advisors Joseph Cavallaro, a professor of electrical and computer engineering, and Gary Woods, a professor in the practice of computer technology and electrical and computer engineering, along with Texas Heart Institute cardiologists Dr. Mehdi Razavi and Dr. Brian Greet. Contributing to the machine learning and sensing aspects of the project were Behnaam Aazhang, a professor of electrical and computer engineering, and Yingyan Lin, a Texas Instruments visiting research assistant professor of electrical and computer engineering.

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[Source/Images: Rice University]