Why Abbott went with a balloon-in-basket design for its Volt PFA catheter

Continuing our series of posts about how Abbott developed and designed its Volt pulsed field ablation (PFA) system, we’ll now look at the cardiac ablation catheter that creates lesions in the heart to treat atrial fibrillation (AFib).

Abbott Electrophysiology Chief Medical Officer Dr. Christopher Piorkowski first discussed this unique design with Medical Design & Outsourcing in January 2024, shortly after Medtronic’s PFA system won the first FDA approval for treating AFib.

After Abbott secured a CE mark for Volt in March 2025, we reconnected with Piorkowski to learn how Abbott dialed in the system’s waveform. In that same interview, he discussed how first-generation PFA lessons led Abbott to take a different approach with the Volt catheter’s design.

“We’ve made great progress,” he said. “… What is unique is the balloon-in-basket design, and that was a deliberate decision. We are the only one that has such a design, and it has very favorable aspects from the perspective of handling, maneuverability and gaining access into the pulmonary veins.”

It’s a familiar approach for physicians who are used to manipulating cryoballoons in the left atrium for cardiac ablation to treat AFib.

“But the benefits go way beyond that,” Piorkowski said.

Abbott designed the balloon — filled with saline and contrast for fluoroscopy visualization — to stabilize the basket, maintain predictable electrode spacing, and maximize energy delivered to the heart tissue for ablation while minimizing waste energy into the blood in the heart’s chamber.

“When you think about an electrical field that is intended to create an ablation, the entire effect of the electrical field depends on the geometry of this field, and the geometry of this field depends on the distance of the electrodes,” Piorkowski said. “[If] the distance of the electrodes is unpredictable and changes by maneuvering the catheter and by having a restless patient and by different anatomical sites, that means you cannot predict the effect of the field, you cannot predict efficacy and safety of a lesion. Now, the balloon prevents all that.”

“The balloon stabilizes the electrodes,” he continued. “The electrodes have very predictable distances. The energy delivery, the lesion development and safety aspect become very controllable, and it’s a big advantage of the balloon-in-basket design.”

The balloon also shields the blood pool from the energy, which has implications both for ablation efficacy and safety.

“Energy that shunts back into the blood pool is wasted,” Piorkowski said. “It doesn’t create a lesion and it is potentially harmful because it can create hemolysis. The balloon prevents all of that. And that is something which in our modeling, our preclinical cases and our clinical cases has consistently held true. … It’s a factor that helps us to reduce actual voltages for the lesion that we create — and we still have superior lesion deaths — and that helps with skeletal muscle recruitment.”

Another Abbott Volt PFA catheter design feature that Piorkowski pointed out is its flat electrodes.

“When you have a round electrode, even if the electrode has tissue contact about half or three quarters of that electrode is still hanging into the blood pool and shooting into the blood pool,” he said. “That’s why our electrodes on Volt are flat. They are flat on the splines, only pointing to the tissue, and the balloon isolates the back end even more.”

Related: Is nanosecond pulsed field ablation the next big step for PFA?