Dr. John Day, Cardiologist

Pulsed Field Ablation for Atrial Fibrillation: A Game-Changer in AFib Treatment

Atrial Fibrillation (AF) is a common cardiac arrhythmia that affects millions of people worldwide. For years, radiofrequency and cryoballoon ablation have been the standard treatments for AF, but a new player has emerged on the scene – Pulsed Field Ablation (PFA). In this article, we’ll explore the mechanisms, pros, and cons of PFA in comparison to the traditional methods, and dive into the recent ADVENT Study, shedding light on its implications for the future of AF ablation.

Comparing Radiofrequency, Cryoballoon, and PFA Ablations

Radiofrequency ablation employs heat energy to create scars in the heart tissue that disrupt AF triggers. Cryoballoon ablation, on the other hand, uses freezing temperatures to achieve the same goal. PFA, however, takes a different approach. It uses precisely controlled electrical fields to ablate heart tissue, making it a non-thermal option. Pros of PFA include shorter procedure times, faster recovery, and reduced risks of complications like esophageal injury, phrenic nerve injury, and pulmonary vein stenosis. However, PFA is still relatively new, and long-term data is limited. Radiofrequency and cryoballoon have a longer track record, and some operators may prefer these methods due to their experience.

The ADVENT Study: PFA vs Radiofrequency or the Cryoballoon

The groundbreaking ADVENT Study randomized patients with paroxysmal AF to receive either PFA or thermal ablation (using radiofrequency or cryoballoon). Paroxysmal Afib is when Afib begins and ends spontaneously. It’s typically an earlier, more manageable stage of Afib. On the other hand, persistent Afib is when Afib doesn’t stop on its own, indicating a more advanced and challenging form of Afib to treat.

The ADVENT Study involved some 65 of the most skilled operators in the U.S. from 30 centers, who were mostly unfamiliar with PFA. The primary endpoint was 1-year freedom from AF without antiarrhythmic drugs and only one ablation procedure. The PFA device used was a first-generation technology. In comparison, radiofrequency and cryoballoon technologies belong to the second, third, or even fourth generation of devices.

I had the privilege of serving on the Data Safety Monitoring Committee for the ADVENT Study, essentially acting as its overseer. This role granted me the opportunity to assess all the data in real-time throughout the study, giving me an early glimpse into the findings well before they were made accessible to the public. To provide full transparency, it’s important to note that I received compensation in the form of an hourly wage for my dedicated hours spent working on the ADVENT Study. This compensation may potentially influence my evaluation of this emerging technology.

Safety: PFA vs  Radiofrequency or Cryoballoon

From a safety perspective, there was no statistical difference in the primary endpoint in the ADVENT Study. This is quite remarkable considering PFA was a brand new device and cardiac EP’s usually need hundreds of cases before their skills are honed with a new technology. And as might be expected, there were some early “learning curve” complications with PFA (cardiac tamponade) that should go away with time and experience. However, the secondary safety endpoint, which was freedom from pulmonary vein stenosis, clearly favored PFA in this study.

Efficacy: PFA vs Radiofrequency or Cryoballoon

Efficacy-wise, both PFA and thermal ablation showed similar results, but PFA procedures were notably quicker. The single procedure success rate was 73% for PFA and 71% in the thermal ablation group (radiofrequency or cryoballoon). There was no statistical difference in these success rates. It’s important to mention that this impressive outcome refers to the percentage of patients who remained free from Afib for one year after a single treatment, and they didn’t require any additional heart rhythm medications.

Durability: PFA vs Radiofrequency or Cryoballoon

When considering long-term effectiveness, it’s crucial to opt for an ablation method that maintains its efficacy. In the ADVENT Study, the rate of needing a repeat Afib ablation within one year was 4.6% in the PFA group, whereas in the thermal group (radiofrequency or cryoballoon), it was 6.6%. Clearly, from a patient standpoint, you want the risk of having to have a repeat ablation as low as possible.

Recovery: PFA vs Radiofrequency or Cryoballoon

One remarkable difference between PFA and thermal ablation (radiofrequency or cryoballoon) was that the procedure times with PFA were much shorter. And in my experience, shorter procedure times often result in faster recoveries.

The Future of AF Ablation with PFA

1. Improved Success Rates: As operators gain experience with PFA and as the technology evolves (the ADVENT Study used a first-generation device), success rates for paroxysmal Afib are expected to increase. For persistent Afib, PFA may offer an advantage in treating the posterior wall of the left atrium, which is often a contributor to ongoing Afib. Thus, I expect success rates for both paroxysmal and persistent Afib to increase over the next 5 years as cardiac EPs gain experience and the technology improves.

2. Safer Procedures: PFA’s shorter procedure times and avoidance of the certain dreaded complications of Afib ablation, like esophageal injury, phrenic nerve injury, and pulmonary vein stenosis, definitely make it a much safer option in my opinion. Also, in addition to much shorter anesthesia times, PFA ablation should help to decrease the risk of post-procedure chest discomfort and fluid overload. This safety profile could encourage more complex Afib cases to be treated with ablation instead of antiarrhythmic drugs.

Should You Wait for PFA?

Not all PFA technologies are equal, and every device company in the Afib space is developing their own PFA device. The PFA device used in the ADVENT Study, from Boston Scientific, is expected to be commercially available in the U.S. by the summer of 2024. Of note, this PFA technology is currently available in Europe.

However, if you need an ablation now, radiofrequency or cryoballoon are well-established and safe options. Waiting for PFA may be an option if your AF is under control and your cardiac EP physician agrees it’s safe to wait.

In Summary

PFA is a promising addition to the arsenal of Afib treatment options. While it currently offers similar success rates for paroxysmal Afib as radiofrequency and cryoballoon, its advantages in safety and procedural efficiency make it a compelling choice. As cardiac EPs gain more experience and technology advances, success rates for Afib ablation should steadily improve. Thus, PFA’s role in treating Afib is expected to grow rapidly, potentially totally reshaping the landscape of Afib ablation in the coming years.

Disclaimer

The information provided in this article is intended for general informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

About the Blog Image

The accompanying blog image for this article is a captivating representation of a catheter ablation procedure for atrial fibrillation, created using AI technology known as DALL-E. This AI-generated image offers an artistic interpretation of what the procedure might entail, adding a unique visual dimension to the discussion.