Taking the Plunge
Until a few years ago, anyone in need of a pacemaker had to rely on technology that has been around, mostly unchanged, for 60 years. Doctors implant a pulse generator under the skin of your chest. From there, they run two long, insulated wires called "leads" down through the veins and into the upper- and lower-right chambers of the heart.
Our single-chamber AVEIR VR system, which received FDA approval in 2022, did away with the wires and jump-started our evolution to "leadless" pacemakers. Smaller than a triple-A battery, they can be implanted directly on the wall of the right ventricle in a minimally invasive procedure.
As the AVEIR VR system developed, the team always had the goal of expanding to both chambers, right atrium and right ventricle, said David Ligon, Director of Clinical Engineering, Leadless Applications at Abbott.
But they still needed to figure out a way for the two pacemakers in this theoretical system to "talk" to each other.
It took months and months of thinking to get over each new wave of challenges, said Matthew Fishler, Director of Systems Engineering, Chief Engineer for the Leadless Platform.
- The two pacemakers needed to be able to communicate on every heartbeat, which happens, oh, about 40 million times a year, on average.
- With such a massive amount of information to process and share, the team needed to engineer something sophisticated enough to handle the load.
- They also needed to come up with a communication method that would not only work without wires but operate with as much battery-preserving energy efficiency as possible.
In the face of this monumental undertaking, they forged something brand-new: a concept they named "i2i" for "implant-to-implant" communication.
Which brings us back to the fish tank, and a key early test. For the dual chamber system to actually work, the team needed to determine if i2i could work in an environment that simulated the inside of the heart.
"We built little pacemaker cans — we called them 'submarines' — with the first test computer chip attached," Fishler recalled. "They were then submerged in a fish tank filled with salt water."
The submarines sent out their pings, and then came a rush of excitement: The experiment worked. The pacemakers transmitted back and forth through the saline solution.
Fishler: "The first time we actually saw this thing working was … "
"Eureka!" Ligon exclaimed.
"It was crazy. And a relief," Fishler said. "It was like, 'Wow, I think we actually have something here.' There was a lot more that needed to be done, but just establishing that this implant-to-implant communication could work was fundamental."