In 1970, the Journal of Electrocardiology published an article by Ohio researcher Dr. J. William Spickler, who claimed to have designed a pacemaker small enough to fit entirely inside the heart's right ventricle. But the device, implanted in dogs, had too many problems to be viable. Forty-five years later, a team of more than 100 Medtronic PLC scientists and engineers based mainly in Minnesota has designed a tiny investigational pacemaker, the Micra, that fits inside the same heart chamber. It's one of two devices being tested on patients today that have a shot at fulfilling Spickler's vision of an "intracardiac pacemaker." (The other one, called the Nanostim, is made by St. Jude Medical.) The Star Tribune spoke with Medtronic's senior principal scientist on the Micra project, Matthew Bonner, who works in Mounds View. Following is an edited transcript:
Q: What makes you want to design medical devices?
A: Growing up, I've always loved to tinker with things. I tore apart my dad's sports car and rebuilt it in high school. Stuff like that. The medical part I enjoy because I like doing things to help people. It's a real standard answer, but especially in this project, where I've actually been out and seen the patients, and how much better they feel, it's just a great feeling. It makes it worth tinkering in the lab.
Q: How does it feel to hold a real Micra today, after years working with prototypes?
A: It's pretty spectacular. The first one we came up with, six years ago, I actually made it. It was a plastic cylinder, and it had paper clip tines (which affix it to the heart wall). Show-and-tell is half my job. The only way I can get people to understand, really, is to make something.
Q: Where did the idea come from to put a pacemaker into a space the size of a pill?
A: The idea is actually not new. A guy named Spickler published an article in 1970 in which he made a device that was not too different from this. But it didn't last very long, and they didn't have the technology to make it do everything that a pacemaker should do, and last as long as it should last.
So when we started this project, the thought was, we have the technology now to make the pacemaker perform all the same activities and things that a normal pacemaker does, but reduce the size by over 90 percent. That's what you are seeing here.
Q: Traditional pacemakers use wires called leads to deliver the electric current that keeps the heart in proper rhythm. Why don't pacemakers like the Micra have leads?
A: One of the big steps was to make the goal that if we can make it small enough to put inside a heart, the electrode can touch the heart tissue directly and now we have a closed system. That is where a lot of the reduction in complications comes from. That was the primary goal of the project. We want to reduce complications.
Q: It must be a challenge to design a device that has the same safety profile as a traditional pacemaker.
A: That was absolutely the goal. One of the big issues starting out is, current pacemakers are quite reliable. So the bar for maintaining that reliability was pretty high. I think that's why we were given the resources to do all the testing we did, so that when we went to the first human implant, we were pretty confident that it would do what was expected.
Q: Is there potential to create new risks with this new device?
A: With anything novel, certainly there are potential risks. But now, first of all we did a tremendous amount of study on this device before we went to people. It was probably analyzed and tested more than any pacemaker we've put out. And then, the second thing is, we have the results on 140 patients who were implanted with this device. And there were no unanticipated events. From that standpoint, there could have been risks, but we haven't seen any yet. It looks like it is going to achieve our goals of performing the way a normal pacemaker does, but in a much smaller package and with fewer complications.
Q: Big device companies like Medtronic are not often seen as being that innovative. As someone who leads a large innovation team, do you think that's true?
A: I don't think it's tough to innovate. I think it's tough to prove that the devices are as safe as they need to be. And that was one thing here. We spent a lot of the energy proving it was safe, proving it would do what it does. I've been making widgets for twenty-something years now. If I want to innovate, I've got the resources within the company. And then it's kind of incumbent on me to figure out, OK, how do I take this idea that I've developed from the [Medtronic internal] resources and move it through the hierarchy, I guess you could say. That to me is probably where the innovation is a little more difficult. Because you've got this idea, but so does … you know, what do we have? 60 people in CRDM (Cardiac Rhythm Disease Management) research? Well there's 60 people making up ideas and we're all trying to get them up. So how do you decide?