Department of Information and Communication Technologies, Universitat Pompeu Fabra' Barcelona' Spain (T.G.-S.' A.I.).
Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomèdica-Sant Pau, CIBERCV, Universitat Autònoma de Barcelona, Spain (G.A.-F., E.J., J.M.G.).
Circ Arrhythm Electrophysiol. 2022 Oct;15(10):e010992. doi: 10.1161/CIRCEP.122.010992. Epub 2022 Sep 30.
Pulsed field ablation (PFA) is a novel nonthermal cardiac ablation technology based on irreversible electroporation. Unfortunately, the characteristics of the electric field waveforms used in clinical and experimental PFA are not typically reported. This study examines the effect of the frequency of biphasic waveforms and compares biphasic to monophasic waveforms.
A total of 29 Sprague-Dawley rats were treated with PFA using an epicardial monopolar electrode. Biphasic waveforms with three different frequencies, 90, 260, and 450 kHz (10 bursts of 100 µs duration at 500 V or 800 V) and monophasic waveforms (10 pulses of 100 µs duration at 500 V) were studied. Collateral neuromuscular stimulation and temperature increase in the point of application were directly measured. Lesion formation was assessed 3 weeks after treatment by histopathologic analysis. Computer simulations were used to estimate the electric field lethal threshold for each condition. A previous in vitro study was performed to draw a complete characterization of the studied dependencies.
Morphometric analysis demonstrated a significant association between chronic lesion size and waveform characteristics. For the same voltage level, monophasic waveforms yielded the largest lesions compared with any of the biphasic protocols (<0.05). Increasing PFA frequency was associated with reduced neuromuscular stimulation but also with reduced ablation efficacy. Maximum absolute temperature increase recorded along a complete treatment was 3 °C. Vascular structures inside the lesions were preserved for all conditions. Computer simulation-based analysis showed that waveform frequency had a graded effect on the lethal electric field threshold, with threshold of 600 V/cm for monophasic waveforms versus 2000 V/cm for biphasic waveforms with a frequency of 450 kHz.
Frequency is a major determinant of efficacy in biphasic PFA. Our results highlight the critical need of disclosing waveform characteristics when reporting the results of different PFA systems.
脉冲场消融（PFA）是一种基于不可逆电穿孔的新型非热心脏消融技术。不幸的是，临床和实验中使用的电场波形的特征通常没有报道。本研究检查了双相波形频率的影响，并比较了双相和单相波形。
总共 29 只 Sprague-Dawley 大鼠使用心外膜单极电极进行 PFA 治疗。研究了三种不同频率的双相波形，90、260 和 450 kHz（在 500 V 或 800 V 时 10 个 100 μs 脉冲）和单相波形（在 500 V 时 10 个 100 μs 脉冲）。直接测量应用点的旁神经肌肉刺激和温度升高。通过组织病理学分析在治疗后 3 周评估病变形成。使用计算机模拟来估计每种情况下的电场致死阈值。之前进行了一项体外研究，以全面描述所研究的依赖性。
形态计量学分析表明慢性病变大小与波形特征之间存在显著关联。在相同的电压水平下，与任何双相方案相比，单相波形产生的病变最大（<0.05）。增加 PFA 频率与减少神经肌肉刺激有关，但也与减少消融效果有关。记录的整个治疗过程中最大绝对温度升高为 3°C。所有条件下的病变内血管结构均得到保留。基于计算机模拟的分析表明，波形频率对致死电场阈值有分级影响，单相波形的阈值为 600 V/cm，而频率为 450 kHz 的双相波形的阈值为 2000 V/cm。
频率是双相 PFA 疗效的主要决定因素。我们的结果强调了当报告不同 PFA 系统的结果时，披露波形特征的重要性。
