2022 AF Symposium

Pulsed Field Ablation Using a Focal Electrode Catheter by Dr. Atul Verma

Note: Pulsed Field Ablation (PFA) is not yet approved by the FDA; Clinical trials are underway.

Dr. Atul Verma of Southlake Regional Health Center in Toronto, Canada presented his talk in a somewhat unusual format. He showed a pre-recorded case of him performing a Pulsed Field Ablation (PFA). Then while the video was playing, he would lower the volume and comment live to the audience. Several panelists and audience members also joined in offering comments during his presentation.

PFA with the Galaxy Centauri System

Dr Atul Verma

Dr. Verma performed an ablation of a patient using the Galaxy Centauri system. The Galaxy system allows EPs to use the same focal catheters and mapping systems they now use when they ablate using point-by-point Radio Frequency (RF) energy However, the Centauri generator produces PFA pulses instead of RF.

The Patient: Was in early persistent A-Fib, with a normal heart and normal-sized atrium.

Dr. Verma’s goal was to isolate the patient’s Pulmonary Veins (PVs) and posterior wall using Pulsed Field Ablation (PFA).

Equipment: He used a standard Carto system and a SMARTTOUCH irrigated catheter to apply the PFA pulses. He also used an irrigated tip catheter (though as he and other panelists acknowledged, Pulsed Field Ablation may not need irrigated catheters). He also used atrial pacing to make sure the patient’s heart rate stayed over 50.

Video of the PFA

On the video, when Dr. Verma would make a point-by-point dot lesion using PFA, the catheter would disappear from the screen but would come back later. He explained that his current Carto system wasn’t designed to handle very large PFA pulses going through the catheter creating an error.

As with RF lesions, dots would appear where a PFA pulse was applied. Dr. Verma stated that, as with RF, the dots do need to be contiguous to avoid gaps.

Dosage: The Galaxy Centauri system can adjust the dose based on patient response (titrate). Medium dosage was 22 amps, high 25 amps. Dr. Verma used the medium dosage on the posterior wall which is thinner. Commenting from the panel, Dr. Vivek Reddy thought the high PFA dosage could be used all the time.

Esophagus Temperature: We watched the video as Dr. Verma positioned the PFA catheter directly over the esophagus and applied high power PFA signals. The temperature in the esophagus before the ablation was 34.7°C and was the exact same temperature after the PFA pulses were applied―demonstrating how safe PFA ablation is.

The PFA pulses obviously didn’t create thermal damage to the esophagus, thereby eliminating the danger of the dreaded atrial esophageal fistula. He also showed ablating the carina ridge area where he used greater contact force and more power.

Dr. Verma then used a Lasso catheter to make sure the Pulmonary Veins (PVs) were isolated. Then he disconnected the Lasso catheter to prevent what he called possible “arcing”.

Procedure Duration: Dr. Verma completed the PFA ablation in 1½ hours which included a 20-minute waiting period.

Experts Panel Discussion

Barium Paste in Esophagus: Dr. Verma raised eyebrows among the panelists when he stated that he used barium paste in the esophagus to better locate and map it.

Dr. Hugh Calkins pointed out that in the past barium paste was aspirated into the lungs and now isn’t used much today. However, Dr. Verma mentioned that he was only using 5 cc of barium, and that this does not affect the lungs at all. Other panelists said that one of the big advantages of PFA is it is unlikely to damage the esophagus, thereby rendering Barium paste unnecessary.

Skeletal Muscle Stimulation: Dr. Verma expressed concern about stimulating skeletal muscle (the vertebrate muscle system) which he avoided by using bi-phasic PFA delivery, breaking PFA pulses into different packets, using a narrower PFA pulse width, and optimizing the PFA wave form. This also avoided generating microbubbles and prevented thermal reaction (heat damage).  

PFA and Coughing: Dr. Verma also described another occurrence which other panelists have noticed as well―patient coughing. Does PFA generate coughing? He asked the panel and attendees if this coughing during PFA comes from J receptors in the PVs or from the bronchi? Can or should this coughing be eliminated by more sedation or by pulling the catheter back? Dr. Andrea Natale suggested that, with PFA, general anesthesia isn’t needed.

Editor’s Comments

The Galaxy Centauri ablation system is probably not ready for prime time yet. Who would want to go back to having to use point-by-point ablation?

Most of the other PFA systems in development don’t need to use point-by-point ablation. They are faster, easier to use, more efficient and safer. However, the Galaxy system is undergoing further refinement, and this is an early concept.

Most labs and EPs would want to use the new catheters with an ablation system designed for PFA, not their traditional catheters. But there are some labs where minimal investment in new systems to get PFA may be an advantage, particularly outside the U.S. to get PFA may be an advantage, particularly outside the U.S.

One approved by the FDA, I expect PFA will change the way catheter ablations are done and will become an innovative and most effective treatment option for A-Fib patients.

We are grateful to both Dr. Verma and to all the other doctors for their creativity and hard work toward development of Pulsed Field Ablation systems.

For the background, concepts and treatment strategies associated with the evolving technology of Pulsed Field Ablation, see my 2020 AF Symposium report: Pulsed Field Ablation—Emerging Tech for Atrial Fibrillation.

If you find any errors on this page, email us. Y Last updated: Tuesday, February 22, 2022

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