Pulsed field ablation system as good as standard-of-care ablation for paroxysmal AF

In the treatment of patients with paroxysmal atrial fibrillation (AF), pulse field ablation (PFA) system appears to yield safety and efficacy outcomes that are noninferior to those of conventional thermal ablation, according to data from the ADVENT trial.

PFA therapy isolates and targets specific characteristics of cardiac tissue by delivering high-energy electrical pulses, according to lead investigator Prof Vivek Reddy of Icahn School of Medicine at Mount Sinai, New York, US.

Reddy, who presented their results at ESC 2023, pointed out that the process addresses the risk of collateral injury to adjacent structures, which is an issue with conventional thermal ablation.

Safety

In ADVENT, the primary safety endpoint of a composite of acute and chronic device- and procedure-related serious adverse events (SAEs) did not differ between the group of patients who underwent PFA (n=305, mean age 62.4 years, 33.8 percent women) and the group of those who underwent thermal ablation (either forced-sensing radiofrequency or cryoballoon ablation; n=302, mean age 62.5 years, 35.4 percent women). The corresponding estimated incidence rates were 2.1 percent and 1.5 percent, with the between-group difference of 0.6 percentage points meeting the criteria for noninferiority. [New Engl J Med 2023;doi:10.1056/NEJMoa2307291]

Of note, the PFA group had one death that was related to mechanical trauma and puncture of the appendage with the ablation catheter, as well as one additional pericardial effusion that was treated with pericardiocentesis. The thermal ablation group, on the other hand, had one case of stroke.

Reddy stated that the death was more likely spurious and not specific to PFA, pointing to the European data collected after the approval and use of PFA (involving 24 centres with 77 operators) wherein mortality was only 1 in 1,568 patients (0.06 percent).

Furthermore, secondary safety endpoint data showed differentially favourable healing with PFA, with significantly less cross-sectional narrowing of the pulmonary valve over 3 months (–0.18 vs –1.18 cm²).

Efficacy

In terms of efficacy, PFA demonstrated acute procedural success (acute procedural vein isolation) and chronic success and was noninferior to thermal ablation. More than 70 percent of patients in either group met the primary efficacy endpoint of freedom from a composite of initial procedural failure, documented atrial tachyarrhythmia after a 3-month blanking period, antiarrhythmic drug use, cardioversion, or repeat ablation through 12 months of follow-up (73.3 percent with PFA vs 71.3 percent with thermal ablation).

When antiarrhythmic drugs were allowed postblanking, the 12-month success probabilities were 78.5 percent with PFA and 76.3 percent with thermal ablation.

The acute pulmonary vein isolation rates were 99.6 percent with PFA and 99.8 percent with thermal ablation.

“It is important to note that procedure performance was better with PFA, with reduced total procedure time, left atrial dwell time of the PFA catheter, and ablation time,” Reddy stated. “This is particularly striking considering that most operators had never used this PFA catheter [but] had performed multiple thousands of thermal ablation procedures.”

Repeat ablation was performed in 4.6 percent of patients in the PFA group and in 6.6 percent of those in the thermal ablation group. The pulmonary vein durability in these re-ablated patients was 64.8 percent and 64.9 percent per vein, respectively.

“Excellent overall clinical performance of the PFA system was seen in this study … which is impressive given the rigor of the trial design and monitoring protocols utilized,” said Reddy. “These highly anticipated findings, together with extensive prior data from Europe, solidify PFA therapy with this system as a preferred ablative treatment modality.”

ADVENT had several limitations, including the lack of study power for superiority analysis, as well as the inability to rule out undetected asymptomatic recurrences of AF or atrial flutter.