Dr. John Day, Cardiologist

New Research in Atrial Fibrillation: Further Evidence of Why Pulsed Field Ablation Is a Game Changer

Atrial fibrillation (AFib) is a common heart condition where the heart beats irregularly and often too fast. It can lead to serious health problems like stroke, dementia, and heart failure. To treat AFib, doctors sometimes use a procedure called ablation, which targets the malfunctioning heart tissue to stop the irregular beats. There are different ways to perform ablation: pulsed field ablation (PFA), radiofrequency ablation (RF), and cryoablation (cryo). All of these ablation types are minimally invasive outpatient procedures done through an IV in the femoral vein, allowing the patient to go home the same day without any incisions or stitches. Let’s explore these methods and find out which one might be the best.

The Basics of Ablation

1. Radiofrequency Ablation (RF): This method uses heat to treat the defective heart tissue causing the irregular beats. The heat is generated by high-frequency electrical currents.

2. Cryoablation (Cryo): This technique uses extreme cold to freeze the problematic heart tissue. It effectively stops the irregular signals by creating a scar.

3. Pulsed Field Ablation (PFA): PFA is a newer method that uses electric fields to treat the faulty heart tissue causing AFib. Unlike RF and Cryo, which rely on thermal (heat or cold) energy, PFA uses non-thermal energy.

Comparing the Methods

Recent studies have compared these three methods to see which is the most effective and safest. The most important study in the field, the ADVENT Study, randomized patients to either PFA or thermal ablation with RF or cryo. Of note, I served on the data safety monitoring board for the ADVENT Study which means I was one of the three “referees” for the study to make sure PFA met all of the safety criteria with this study. Here’s what we found:

Methods

In the ADVENT study, patients with symptomatic paroxysmal AF (PAF) that did not respond well to medications were randomly assigned to undergo either PFA or thermal ablation with RF or cryo. Here’s how the study was conducted:

1. Monitoring: After the ablation procedure, patients had their heart rhythms monitored with ECG recordings every week or whenever they had symptoms. They also wore 72-hour Holter monitors at 6 and 12 months after the procedure to check for any AFib recurrences.

2. Atrial Arrhythmia Burden Calculation: The percentage of time patients experienced atrial arrhythmias (AA) was calculated from the data collected from the ECGs and Holter monitors.

3. Quality-of-Life Assessments: Patients’ quality of life was assessed at the beginning of the study and again at 12 months.

Results

1. Participants: The study included 593 patients, with 299 randomized to PFA and 294 receiving thermal ablation with either RF or cryo based on physician choice.

2. Atrial Arrhythmia (AA) Burden and Quality of Life: It was found that having an AA burden exceeding 0.1% was linked to a significantly lower quality of life and more clinical interventions, such as redo ablations, cardioversions (procedures to restore normal heart rhythm), and hospitalizations.

3. Effectiveness of PFA: More patients who underwent PFA had a residual AA burden of less than 0.1% compared to those who had thermal ablation. This indicates that PFA was more effective in keeping patients in normal rhythm. The odds ratio (OR) for this was 1.5, meaning PFA patients were 1.5 times more likely to have a low AA burden (meaning a successful procedure) than those who had thermal ablation with RF or cryo.

Key Takeaways from the ADVENT Study

1. Lower AF Burden with PFA: PFA was linked to a lower AF burden compared with thermal ablation at 1 year.

2. Quality of Life: Atrial arrhythmia burden less than 0.1% was linked to maximal quality of life and fewer returns to the hospital.

3. Superiority of PFA: PFA lowered the odds of high residual atrial arrhythmia burden compared with thermal ablation for patients with atrial fibrillation at 1 year. This means patients were 1.5 times more likely to have had a successful ablation with PFA, achieving an AA burden of less than 0.1%. In other words, their hearts were in rhythm more than 99.9% of the time.

As presented at the annual scientific sessions of the Heart Rhythm Society (Heart Rhythm 2024), the results showed that PFA not only matched but exceeded thermal ablation (RF or cryo) in both effectiveness and safety. PFA procedures were faster and had fewer complications, leading to an overall better outcome for patients.

Dr. Day’s Views on this Study

Having served as one of the three physicians on the data safety monitoring board of the ADVENT Study, I reviewed the data submitted by every hospital involved. While I was impressed with the safety, effectiveness, and speed at which atrial fibrillation ablation procedures were performed using PFA in the study, it does not compare to the results we are currently seeing in our practice at St. Mark’s Hospital in Salt Lake City, Utah.

With further modifications to the PFA technology used in the ADVENT Study (the specific type of PFA we are using at St. Mark’s Hospital), we are seeing an even safer procedure with improved success rates compared to those reported in the study. Although there is still a risk of bleeding from the catheter entry at the femoral vein or the heart, and a stroke risk, many of the complications we previously worried about—such as pulmonary vein stenosis, esophageal injury, permanent phrenic nerve injury, stiff left atrial syndrome, pericarditis, and acute congestive heart failure—seem to have disappeared with PFA. Even our most challenging cases, which couldn’t be treated successfully with older technologies like RF, can usually be effectively treated with PFA.

In my 25 years of performing AFib ablations, I have never seen a technology perform as well as the PFA we are now using. Indeed, this PFA works so well that I now use it for every AFib ablation procedure.

Conclusion

Ablation is a crucial treatment for atrial fibrillation, and choosing the right method can make a big difference. Pulsed field ablation (PFA) stands out as a faster, safer, and more effective option compared to traditional thermal methods like RF and Cryo. If you or a loved one is considering ablation for AF, it’s worth discussing PFA with your doctor to see if it’s the right choice for you.

Disclosure

The information provided in this blog is intended for educational purposes only and should not be considered medical advice. Always consult with your healthcare provider or a qualified medical professional before making any decisions regarding medical treatments or procedures. The results and findings discussed, including those from the ADVENT study, reflect current research and clinical practices as of the date of publication. Individual patient outcomes may vary, and the choice of treatment should be tailored to each patient’s specific condition and needs. The author of this blog receives an hourly reimbursement for time spent from three different manufacturers of pulsed field ablation (PFA) devices to assist with PFA studies, consulting, and educating physicians on this new technology.

About the Photo

The photo attached to this article was taken today from the Salt Lake City lookout portion of the Desolation Trail in Millcreek Canyon. The weather was perfect this morning, and my 16-year-old daughter and I thoroughly enjoyed our 4.8-mile hike/run with a 1,237-foot vertical gain.