by Jane Ehrhardt

In December, Medtronic landed the first FDA approval for a catheter system that delivers a new form of ablation treatment for atrial fibrillation (AFib). “It allows for the energy delivery to be faster which can help reduce complications, and there are signals that it is more effective,” says Macy Smith, MD, cardiac electrophysiologist with Alabama Cardiovascular Group at Grandview Medical Center, which has been part of the clinical trials on the new approach since its early stages.

To date, the most common type of ablative procedure for AFib is a form of thermal ablation where Radiofrequency (RFA) energy produces heat to form scar tissue on the areas of atrial heart tissue that are out of sync with the heart’s rhythm. The new approach, called pulsed field ablation (PFA) offer a non-thermal (not caused by changes in heat) approach. PFA uses microsecond pulses of high-voltage electrical fields to create small holes in the cells and selectivity deactivates them.

Most of the three to six million AFib patients in the U.S. treat their condition with oral medications, but approximately four percent require interventional techniques, including catheter ablation and surgical ablation. “Ablation has become a cornerstone for the treatment of AFib because the medicines don’t work that well long-term,” Smith says. With the aging U.S. population, the number of AFib patients is projected to reach 16 million by 2050.

With at least four PFA catheter systems having now passed through pivotal trials in the U.S., more PFA devices will likely be hitting the market soon. Boston Scientific already received the FDA nod for their system in January, and Johnson & Johnson is expected to not be far behind.

In Europe, PFA has been approved for several years. “They’ve done tens of thousands of cases, and it appears to be safer and at least as effective, potentially more effective, than traditional catheter ablation” Smith says. “We’ll know more in the coming years once we do more cases.

“With the PFA system the risk to surrounding tissues is lower than with traditional catheter ablation. When you use thermal energy, there’s a small, but real risk of collateral damage to nearby tissues.”

One of the primary but minimal risks with ablation is damaging the esophagus, which sits right behind the left atrium, a primary spot for AFib problem tissue. “However, with PFA you can ablate in close proximity with other structures with a very low chance of any damage there,” Smith says. European PFA outcomes have reported zero esophageal injuries.

“The energy delivery is fast and easily reproducible so you can shorten steps, making it faster. And usually faster is safer,” Smith says. “A conventional catheter procedure takes me around 90 minutes, whereas a PFA takes less than an hour, and that’s with a learning curve on board. Once you get beyond that, it’s a significant change.”

The shortened time between the two ablation processes derives from the faster delivery of energy over a potentially wider area with PFA which means less ablation lesions have to be performed.

The size of the ablation area generated by the PFA depends on the platform used. There are variable basket and flower shapes generating the fields which allow the device to adapt to individual patient anatomies. “With the wider fields, they can potentially ablate around an entire pulmonary vein with one application,” Smith says. “That’s not possible with the thermal catheter, which limits the surgeon to touching the tissue in small spots.

“PFA has fewer steps and is easier to perform so there is less of a learning curve, making training for the new technique less of a time commitment for surgeons.”

The shorter PFA procedure time means less time under anesthesia, which can lessen the drug’s post-operative effects. PFA patients are also spared the common chest pains caused by the irritated tissue from the thermal procedure.

With multiple devices having attained FDA approval, PFA systems are now breaking onto the market. Grandview expects to begin performing pulsed field ablations this month. “Over time, I think PFA will phase out catheter ablation,” Smith says. “Real world data will tell us in the coming years. But I expect it to completely change the landscape of ablation for atrial fibrillation.”