Low-energy surface stimulation achieved defibrillation with energy <60 mJ when arrhythmia complexity was minimal and electrodes captured >75% of the excitable gap.
Low-energy, single-pulse surface stimulation can defibrillate large mammalian ventricles with energies below the human pain threshold (<100 mJ) by targeting the excitable gap.
BackgroundStrong 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.ObjectiveThe purpose of this study was to determine the conditions under which low-energy surface stimulation defibrillates large mammalian ventricles.MethodsLow-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.ResultsIn 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 75% of the EG, which blocked reentry 75% of the EG. 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 75% of the EG, which blocked reentry 75% of the EG.
Moreno et al. (Wed,) conducted a other in Ventricular fibrillation. Low-energy, single-pulse surface stimulation was evaluated on Defibrillation success. Low-energy surface stimulation achieved defibrillation with energy <60 mJ when arrhythmia complexity was minimal and electrodes captured >75% of the excitable gap.