February 06, 2020
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Trial to evaluate pulsed field ablation for AF

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Atul Verma

Medtronic announced that the FDA has approved an investigational device exemption trial to assess the safety and effectiveness of a pulsed field ablation system for the treatment of patients with atrial fibrillation.

The pulsed field ablation system (PulseSelect, Medtronic) is a nonthermal option for ablation and may be an alternative to traditional methods like cryoablation and radiofrequency ablation, according to a press release from the company.

Healio spoke with Atul Verma, MD, director of the heart rhythm program at Southlake Regional Health Centre in Newmarket, Ontario, Canada, and principal investigator of the PULSED AF trial, to learn more about the technology and details about the trial.

Question: How does this technology work?

Answer: Irreversible electroporation, or pulsed field ablation, is completely different from the traditional heating or freezing energy sources that we use. It delivers electricity into the heart cells in a pulsed fashion; several very small pulses of electricity are delivered into the tissue and cause the tissue to selectively be destroyed in the areas that we want to destroy it without causing any heating or cooling. It’s what we call a nonthermal energy source.

Q: What are the potential advantages for patients?

A: The biggest advantages are that, No. 1, the safety profile of pulsed field ablation seems to be better than that of traditional thermal sources of energy. When you heat or freeze tissue, there’s also the potential to heat or freeze other structures in the chest like the esophagus, the lung or the nerves. That can potentially cause collateral damage. Fortunately, the incidence of that is really low, but it is always a potential. Pulsed field ablation seems to be very selective just for cardiac tissue and does not seem to affect esophageal tissue, nerve tissue or lung tissue in the same way. We can deliver the energy that we want to the cells that we want without the potential of causing collateral damage.

The other big advantage is in the speed of delivery. When you’re either heating or freezing tissue, you have to leave the catheter there for a period of time until the tissue is completely cooked, so to speak, or frozen. With electrical fields, the effect on the cells is nearly instantaneous, so you can deliver the energy, eliminate the targets that you want to eliminate within a second or two and then you can move on to do your further deliveries.

The safety and the efficiency of delivery are the two biggest advantages.

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Q: Can you tell us about the PULSED AF trial?

A: The purpose of the trial is to evaluate pulsed field ablation in a variety of different patients with AF. There will be patients with paroxysmal AF and persistent AF.

We will be starting off with the first-in-human early evaluation of the technology, which will be done at four centers in 20 patients. From there, there are plans certainly to launch into a much larger study, which would look for approval of the technology in the United States and other jurisdictions.

Q: What do you hope to learn from the trial?

A: We’re hoping to learn lots of things. First and foremost is the energy source as effective as the traditional thermal energy sources. From what we’ve seen in the preclinical work — and Medtronic has certainly done a lot of preclinical work leading into this trial — we have every reason to believe that the therapy is going to be just as effective as any of the thermal sources of energy.

We want to prove the safety profile. Again, even though we’ve done a lot of preclinical work to prove that it is safer, we obviously want to see that in a larger clinical trial.

Finally, we also want to look at the efficiency of the technique. If we can demonstrate that this is much more efficient, safe and efficacious than other energy sources, then this can be a real game changer.

Q: How many patients are you hoping to enroll?

A: The full sample size has not yet been decided upon, but we hope to enroll another four patients for a total of five for the pilot. Right now, Australia and Canada have been the first two countries to enroll in early feasibility. We have performed procedures on six patients so far, and there are another four cases coming up in the next 2 weeks.

Q: Although it’s still in its early stages, when you do anticipate completing the PULSED AF trial?

A: If we launch into the larger trial, you can anticipate that it’s going to take some period of time to enroll the patients and then follow them up for a year afterward. I have a feeling that enrollment is going to go fast because if the experience from the first six patients says anything, it’s that the investigators are really excited about this. Investigators are going to fight to get into this study and are going to be happy to enroll their patients.

Patients are also going to be happy to receive their therapy using this technology. In fact, my first patient that I enrolled is an electrical engineer, and he told me he absolutely refuses to get his ablation done by anything except pulsed field ablation. He was convinced in the safety and efficacy of this technology.

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Q: If the trial is positive, what type of implications do you think it will have on clinical practice?

A: This is going to be a revolutionary technology. It is definitely going to change how this field operates in the future. It’s great that Medtronic and their team are very much the first company to be leading their way to this kind of a trial. – by Darlene Dobkowski

For more information:

Atul Verma, MD, can be reached at atul.verma@utoronto.ca; Twitter: @atulverma_md.

Disclosures: The PULSED AF trial is sponsored by Medtronic. Verma reports he received consultant fees from Biosense Webster, Boston Scientific and Medtronic.