In the single-arm inspIRE study conducted by Mattias Duytschaever and team, a novel pulsed-field ablation system using the Varipulse catheter and the Trupulse generator (Biosense Webster) appeared to effectively treat patients with drug-refractory paroxysmal atrial fibrillation (AF). The findings of this study were published in the Circulation: Arrhythmia and Electrophysiology.
The PFA system was used to perform pulmonary vein isolation (PVI) on the research participants, using at least 12 applications per vein. Adenosine/isoproterenol was also given to ensure that the entry block had been achieved. Wave I evaluated early safety, taking into account PV stenosis, silent cerebral lesions (SCLs), and esophageal lesions. Wave II (pivotal phase) examined the primary efficacy of the verified PVI with independence from recorded atrial arrhythmia at 12 months, as well as the primary safety of the incidence of early onset primary adverse events (PAEs) (12M). When 30 patients completed 12M follow-up (FU) and all subjects reached 3M FU, the study's design called for an interim analysis to identify early success.

The key findings of this study were:
226 participants were enrolled across 13 facilities in Europe and Canada, completed the requirements for safety and efficacy assessments, and were given PFA.
Wave I didn't show any PV stenosis or heat lesions in the esophagus.
With the implementation of process improvements, such as a 10-second delay between PFA applications, only 4 of the 39 participants with cerebral MRI who initially showed SCLs were found to have them.
There were no PAE reports during the Wave II phase. Early success was declared when 83 patients attained 12M FU.
PVI without acute reconnection was accomplished in 97.1% of the targeted veins with 100% entry block.
At the time of interim analysis, the primary efficacy goal for Wave II was 70.9% according to Kaplan Meier; 12M independence from symptomatic AF/atrial flutter/atrial tachycardia recurrent and repeat ablation were both 78.9% and 92.3%.
The durations of the whole operation and the actual PFA were 70.1 ± 27.7 min and 26.7 ± 14.0 min, respectively.
Reference:
Duytschaever, M., De Potter, T., Grimaldi, M., Anic, A., Vijgen, J., Neuzil, P., Van Herendael, H., Verma, A., Skanes, A., Scherr, D., Pürerfellner, H., Rackauskas, G., Jaïs, P., & Reddy, V. Y. (2023). Paroxysmal AF Ablation Using a Novel Variable-Loop Biphasic Pulsed Field Ablation Catheter Integrated With a 3D Mapping System: 1-Year Outcomes of the Multicenter inspIRE Study. In Circulation: Arrhythmia and Electrophysiology. Ovid Technologies (Wolters Kluwer Health). https://doi.org/10.1161/circep.122.011780