Nanosecond Pulsed-Field Ablation Reduces Neuromuscular Stimulation and Widens the Safety Window.

BACKGROUND

Microsecond pulsed field ablation (PFA) is limited by severe neuromuscular stimulation (NMS). Nanosecond PFA (nsPFA) is a promising alternative, but quantitative comparisons of NMS under matched energy conditions are lacking.

OBJECTIVES

This study sought to quantitatively compare NMS intensity between energy-matched microsecond PFA (μsPFA) and nsPFA, and to evaluate the dose-response of NMS for both modalities.

METHODS

A total of 6 dogs underwent randomized pulmonary vein isolation (PVI) and atrial ablation with μsPFA or nsPFA at matched high (358.2 J) and low (108.9 J) energy. NMS was precisely quantified using inertial measurement units to measure acceleration, angular velocity, and contraction energy. Ablation effectiveness was assessed via acute PVI and 14-day histology.

RESULTS

All high-dose protocols for both modalities achieved 100% acute PVI and transmural lesions. NMS, however, differed profoundly. μsPFA induced contractions in 100% of applications, whereas nsPFA induced 0% at low doses and 61.5% at high doses. At high doses, μsPFA produced 1.89-fold greater peak acceleration (P < 0.001) than nsPFA. μsPFA also produced approximately twice as many contraction events as nsPFA (P = 0.006). Although peak NMS metrics increased with dose for both modalities, the absolute NMS intensity of high-dose nsPFA remained lower than even low-dose μsPFA. Notably, nsPFA contraction energy did not reach statistical significance despite higher energy delivery (P = 0.145), whereas μsPFA showed a significant surge (P = 0.001).

CONCLUSIONS

nsPFA effectively achieves acute PVI and transmural lesions while markedly reducing NMS compared with μsPFA. Its attenuated dose-response and lower absolute stimulation magnitude provide a wider safety window, potentially allowing for higher-energy delivery to optimize therapeutic effectiveness without compromising patient tolerance.