High-Voltage Nanosecond Pulse Field Ablation Using a Compliant Circular Catheter to Treat Atrial Fibrillation

BACKGROUND: Most pulsed field ablation (PFA) technologies for atrial fibrillation use microsecond-scale pulses. Nanosecond pulses, by virtue of their short duration, enable larger pulse amplitudes to project lesion depth, without near-field thermal effects. OBJECTIVES: The goal of this study was to determine the outcomes of treating paroxysmal atrial fibrillation using a novel circular nanosecond PFA (nsPFA) catheter. METHODS: In a first-in-human study of patients with symptomatic paroxysmal atrial fibrillation, the nsPFA catheter was used to deliver 2.5-second or 5-second applications. Invasive remapping assessed lesion durability at 2 to 3 months, with additional nsPFA for incomplete lesions. Follow-up included transtelephonic monitoring and Holter monitoring at 6 and 12 months. RESULTS: At 3 centers, 177 patients (mean age 61 ± 10 years; 36% female; left atrial diameter 41 ± 5 mm) underwent pulmonary vein isolation (PVI) using 2.5-second (n = 36 patients) or 5-second (n = 141) applications. Additional ablation was at the posterior wall (n = 87), cavotricuspid isthmus (n = 11), or mitral isthmus (n = 29). All (100%) lesions were acutely successful, with transpired PVI time of 12 ± 5 minutes, and total left atrial dwell time for the nsPFA catheter of 19 ± 13 minutes. Total procedure and fluoroscopy times were 61 ± 27 minutes and 9 ± 6 minutes, respectively. Three (of 177 [1.7%]) primary serious adverse events occurred: inflammatory pericardial effusion, hemolysis with acute kidney injury, and stroke. Post procedure brain magnetic resonance imaging (35 patients) revealed 11.4% silent cerebral events (DWI+ / ADC-reduced) and 11.4% silent cerebral lesions (SCE plus FLAIR+). PVI durability with the 5-second applications was 91%. The 1-year estimate for freedom from atrial arrhythmia was 89.7% (95% CI: 80.5%-94.6%). CONCLUSIONS: nsPFA demonstrated reasonable safety, good lesion durability, and favorable 1-year clinical effectiveness. (Evaluation of the CellFX® Nano-Pulsed Field Ablation [PFA] 360 Catheter Endocardial Ablation System for the Treatment of Atrial Fibrillation. NCT06696170).