Nanosecond and microsecond pulse field ablation for paroxysmal atrial fibrillation: Muscle response, procedural safety, and 6-month outcomes.

BACKGROUND

Nanosecond pulse field ablation (nanoPFA) is an emerging non-thermal modality that may reduce muscle contractions and enable atrial fibrillation (AF) ablation under conscious sedation.

OBJECTIVE

This study aimed to compare the muscle response, safety, and 6-month outcomes between nanoPFA and microsecond PFA (microPFA).

METHODS

Patients with symptomatic paroxysmal AF underwent nanoPFA under conscious sedation or microPFA under general anesthesia. In the nanoPFA group, muscle contraction, pain (Visual Analogue Scale [VAS]), and patient experience (Likert scale questionnaire) were assessed. Outcomes were evaluated at 3 and 6 months. Propensity score matching (PSM) was performed as sensitivity analysis.

RESULTS

Among 151 patients (60.2 ± 11.4 years, 32.5% female), 57 received nanoPFA and 94 underwent microPFA. Pulmonary vein and superior vena cava isolation was completed in all, with no device-related complications. During nanoPFA, muscle contraction was absent in 43.9%, slight in 47.4%, and severe in 8.8%, most frequently at the right superior pulmonary vein. Most patients reported mild/no discomfort (VAS 0-4: 71.9% [41/57]); none reported severe pain, and 87.7% preferred conscious sedation. Six-month Kaplan-Meier freedom from any atrial tachyarrhythmia was 91.8% with nanoPFA and 83.9% with microPFA (log-rank P = .57); after PSM, 6-month freedom remained similar between groups (90.0% vs 88.9%, log-rank P = .56).

CONCLUSION

NanoPFA performed under conscious sedation provides comparable safety and similar 6-month arrhythmia outcomes to microPFA under general anesthesia, with minimal pain and muscle responses, supporting the feasibility of a conscious-sedation workflow in our center.