Exploring the latest data in PFA and leadless conduction system pacing

The first-generation human study enrolled 19 patients. Reddy said investigators were pleased with the maneuverability and pacing performance of the system.

“We were very happy that with the deflectible sheath," he said. "We could position it everywhere we wanted."

However, the study also revealed an important mechanical issue. Three device dislodgements occurred during follow-up, including two identified before hospital discharge and one occurring within the first month after implantation. In all cases, the devices were removed and replaced with conventional leadless pacemakers. He said this might be corrected with a redesign of the anchor system to prevent the device from unscrewing from the myocardium.

“We really do believe that it's an issue of having some anti-rotation capabilities,” Reddy said, noting that Abbott has already modified the design to address the issue.

Despite the setbacks, Reddy said this may be future of leadless conduction system pacing.

“I’m actually very optimistic about it,” he said, adding that an early feasibility study in the United States could begin before the end of the year after further testing.

Emerging PFA technologies

Reddy also presented data from three emerging PFA technologies aimed at improving lesion durability, procedural efficiency and visualization during atrial fibrillation ablation.

One study evaluated the Boston Scientific Faraflex focal PFA catheter, a nine-millimeter basket-shaped device used for pulmonary vein isolation (PVI) and additional linear lesions. Conducted at three European centers, the study enrolled approximately 105 patients.

Reddy said a key strength of the study was the inclusion of repeat remapping procedures to directly assess long-term pulmonary vein durability in the study

“The majority of patients came back, so we're able to get very high-quality data and say, ‘Yes, this is working pretty well,'” he said.

The favorable results have supported plans for a U.S. pivotal trial expected to begin within months.

A second study, the Vision AF trial, evaluated the CardioFocus OptiShot balloon-based PFA catheter featuring an integrated endoscope that allows physicians to directly visualize tissue contact during ablation.

As the balloon contacts the pulmonary vein, operators can visually distinguish tissue contact from circulating blood, potentially improving lesion consistency, and avoiding hemolysis caused by PFA energy being delivered into the blood pool.

“Literally it's red vs. white, so it's about as simple as you can imagine,” Reddy said.

The 50-patient study demonstrated what Reddy described as “excellent durability,” with the final ablation strategy achieving 100% PVI durability during remapping procedures. Six-month follow-up showed arrhythmia-free survival approaching 90%.

Reddy said the direct visual guidance capability may represent an important advance over traditional surrogate markers of tissue contact.

The third study examined the the Pulse Biosciences nanosecond pulsed field ablation (nsPFA) system in the U.S. NANOPULSE‑AF study. It is designed to deliver shorter-duration energy pulses than conventional microsecond systems. The concept behind nanosecond technology is that compressing the waveform allows delivery of higher voltages, while minimizing near-field heating. This can help speed up procedures while maintaining safety.

The first-in-human study enrolled 177 patients across three European centers and demonstrated more than 90% pulmonary vein durability, along with the ability to create posterior wall and linear lesions. Clinical success rates approached 90% at one year, according to Reddy.

However, the study did identify two notable complications, including one stroke and one case of hemolysis-associated renal failure requiring temporary dialysis. Reddy said the renal complication occurred early in the learning curve before operators adopted routine post-procedure fluid administration to combat hemolysis.

“After that patient, we obviously learned and we started giving fluids to patients after the procedure. After that, we did not have any such renal failure,” Reddy explained.

He also emphasized the procedural efficiency achieved with the nanosecond PFA platform, particularly through integration with advanced mapping systems.

“The isolation takes five to seven minutes, which is quite remarkable,” he said.

While shaving a few minutes off PVI may seem incremental, Reddy said efficiency gains could ultimately enable physicians to perform more comprehensive ablation strategies during a single procedure.

“When you can do that part really quickly, then it makes sense to spend more time looking for other things,” he said.

He said these advances in PFA technology, combined with a flood of new FDA-cleared PFA technology in recent years, may require new head-to-head comparison studies to see which systems have the best outcomes.

“One of the things we need in our field is some real randomized studies comparing technologies. Now the technologies are getting mature enough, it makes sense to start doing that,” Reddy said.