IEEE Trans Biomed Eng. 2021 Jun;68(6):1999-2010. doi: 10.1109/TBME.2021.3049221. Epub 2021 May 21.
High-frequency irreversible electroporation (H-FIRE) is a tissue ablation modality employing bursts of electrical pulses in a positive phase-interphase delay (d)-negative phase-interpulse delay (d) pattern. Despite accumulating evidence suggesting the significance of these delays, their effects on therapeutic outcomes from clinically-relevant H-FIRE waveforms have not been studied extensively.
We sought to determine whether modifications to the delays within H-FIRE bursts could yield a more desirable clinical outcome in terms of ablation volume versus extent of tissue excitation.
We used a modified spatially extended nonlinear node (SENN) nerve fiber model to evaluate excitation thresholds for H-FIRE bursts with varying delays. We then calculated non-thermal tissue ablation, thermal damage, and excitation in a clinically relevant numerical model.
Excitation thresholds were maximized by shortening d, and extension of d up to 1,000 μs increased excitation thresholds by at least 60% versus symmetric bursts. In the ablation model, long interpulse delays lowered the effective frequency of burst waveforms, modulating field redistribution and reducing heat production. Finally, we demonstrate mathematically that variable delays allow for increased voltages and larger ablations with similar extents of excitation as symmetric waveforms.
Interphase and interpulse delays play a significant role in outcomes resulting from H-FIRE treatment.
Waveforms with short interphase delays (d) and extended interpulse delays (d) may improve therapeutic efficacy of H-FIRE as it emerges as a clinical tissue ablation modality.
高频不可逆电穿孔（H-FIRE）是一种组织消融方式，采用正相间延迟（d）-负相间脉冲延迟（d）模式的电脉冲爆发。尽管有越来越多的证据表明这些延迟的重要性，但它们对临床相关 H-FIRE 波形治疗效果的影响尚未得到广泛研究。
我们旨在确定 H-FIRE 爆发中的延迟变化是否可以在消融体积与组织激发程度方面产生更理想的临床结果。
我们使用改进的空间扩展非线性节点（SENN）神经纤维模型来评估具有不同延迟的 H-FIRE 爆发的激发阈值。然后，我们在临床相关的数值模型中计算了非热组织消融、热损伤和激发。
通过缩短 d，激发阈值最大化，而将 d 延长至 1000μs 会使激发阈值至少增加 60%，与对称爆发相比。在消融模型中，长的脉冲间延迟降低了爆发波形的有效频率，调节了场重新分布并减少了热产生。最后，我们从数学上证明，可变延迟允许增加电压和更大的消融，同时保持与对称波形相似的激发程度。
相间和脉冲间延迟在 H-FIRE 治疗结果中起着重要作用。
具有短相间延迟（d）和延长脉冲间延迟（d）的波形可能会提高 H-FIRE 的治疗效果，因为它作为一种临床组织消融方式出现。
