The world’s largest medical device manufacturer achieved that milestone about 15 years after one of its engineers, Mark Stewart, coined the term “pulsed field ablation” in a research paper about using electroporation for cardiac ablation.
“Mark continued to optimize and test waveforms,” Tim Laske, VP of research and business development for Medtronic Cardiac Ablation Solutions, said in an interview with Medical Design & Outsourcing. “He had an internal grant from Medtronic under a program called Quest where engineers are given a certain amount of seed money, and Mark went into the lab and designed some experiments, had a lot of waveforms that didn’t work, and then suddenly came across the one that did. He brought the histological results to us and they fell into the too-good-to-be-true category.”
“We thought, ‘OK, if it is true, we really need to understand this,’” Laske continued. “And at that point, we launched a series of tests on selectivity: does it just impact the myocytes, or could you injure the esophagus, phrenic nerve, etc.? We showed that these particular waveforms had very little amount of hemolysis created, that they created predictable fields with this particular catheter, they were not proarrhythmic — on and on, there’s so many different things you need to consider. And so we settled in on that waveform.”
Related: What’s so special about pulsed field ablation? Medtronic EVP Sean Salmon explains
Medtronic is working toward FDA approval for more PFA systems developed by Affera (which Medtronic bought in 2022), but PulseSelect is a very different catheter than the Affera Sphere-9 and Sphere-360.
All of the PFA catheters in Medtronic’s portfolio are designed for both ablation and cardiac mapping, and they all rely on nitinol as a key material. Nitinol (a nickel-titanium alloy with superelastic and shape memory properties) allows the catheter tips to compress for minimally invasive delivery to the heart before expanding to a pre-set shape.
“PulseSelect has nitinol superstructure, which allows it to compress down, and that’s delivered through a 10-Fr catheter, and then it’s deployed in a very predictable shape,” Laske said.
That loop shape allows for single-shot ablation, which is the delivery of energy across multiple parts of the pulmonary vein for a procedure that can be simpler and faster. That tissue-selective energy kills cardiac myocytes to block irregular heart signals that cause AFib, but spares phrenic nerves and nerves in the esophagus.
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