IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France.
IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, U1045, Bordeaux, France; INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France.
Heart Rhythm. 2022 Feb;19(2):308-317. doi: 10.1016/j.hrthm.2021.10.006. Epub 2021 Oct 12.
Strong electric shocks are the gold standard for ventricular defibrillation but are associated with pain and tissue damage. We hypothesized that targeting the excitable gap (EG) of reentry with low-energy surface stimulation is a less damaging and painless alternative for ventricular defibrillation.
The purpose of this study was to determine the conditions under which low-energy surface stimulation defibrillates large mammalian ventricles.
Low-energy surface stimulation was delivered with five electrodes that were 7 cm long and placed 1-2 cm apart on the endocardial and epicardial surfaces of perfused pig left ventricle (LV). Rapid pacing (>4 Hz) was used to induce reentry from a single electrode. A 2 ms defibrillation pulse ≤0.5 A was delivered from all electrodes with a varied time delay from the end of the induction protocol (0.1-5 seconds). Optical mapping was performed and arrhythmia dynamics analyzed. For mechanistic insight, simulations of the VF induction and defibrillation protocols were performed in silico with an LV model emulating the experimental conditions and electrodes placed 0.25-2 cm apart.
In living LV, reentry was induced with varying complexity and dominant frequencies ranging between 3.5 to 6.2 Hz over 8 seconds postinitiation. Low-energy defibrillation was achieved with energy <60 mJ and electrode separations up to 2 cm for less complex arrhythmia. In simulations, defibrillation consistently occurred when stimulation captured >75% of the EG, which blocked reentry <2.9 mm in front of the leading reentrant wavefront.
Defibrillation with low-energy, single-pulse surface stimulation is feasible with energies below the human pain threshold (100 mJ). Optimal defibrillation occurs when arrhythmia complexity is minimal and electrodes capture >75% of the EG.
强电击是心室除颤的金标准，但会引起疼痛和组织损伤。我们假设，用低能量表面刺激靶向折返的可兴奋间隙（EG）是一种对心室除颤损伤较小且无痛的替代方法。
本研究旨在确定低能量表面刺激除颤大型哺乳动物心室的条件。
用 5 个长 7 厘米、间隔 1-2 厘米的电极为心内膜和心外膜表面的灌注猪左心室（LV）提供低能量表面刺激。快速起搏（>4 Hz）用于从单个电极诱导折返。从所有电极发送一个 2 ms 的除颤脉冲，<0.5 A，其延迟时间从诱导方案结束开始变化（0.1-5 秒）。进行光学映射并分析心律失常动力学。为了深入了解机制，在 LV 模型中模拟 VF 诱导和除颤方案，并在与实验条件和电极放置间隔 0.25-2 cm 的情况下进行了模拟。
在活 LV 中，诱导折返的复杂性不同，主导频率在诱导后 8 秒内从 3.5 到 6.2 Hz 变化。低能量除颤可在<60 mJ 的能量和电极间隔长达 2 cm 时实现，对于较简单的心律失常。在模拟中，当刺激捕获>75%的 EG 时，除颤始终发生，EG 阻止折返的距离<2.9 mm，位于领先折返波阵面的前面。
用低能量、单次脉冲表面刺激进行除颤是可行的，能量低于人类疼痛阈值（100 mJ）。当心律失常复杂性最小且电极捕获>75%的 EG 时，最佳除颤发生。
