Abstract
AimsRecently, a new defibrillation modality using nanosecond pulses was shown to be effective at much lower energies than conventional 10 millisecond monophasic shocks in ex vivo experiments. Here we compare the safety factors of 300 nanosecond and 10 millisecond shocks to assess the safety of nanosecond defibrillation.Methods and resultsThe safety factor, i.e. the ratio of median effective doses (ED50) for electroporative damage and defibrillation, was assessed for nanosecond and conventional (millisecond) defibrillation shocks in Langendorff-perfused New Zealand white rabbit hearts. In order to allow for multiple shock applications in a single heart, a pair of needle electrodes was used to apply shocks of varying voltage. Propidium iodide (PI) staining at the surface of the heart showed that nanosecond shocks had a slightly lower safety factor (6.50) than millisecond shocks (8.69), p = 0.02; while PI staining cross-sections in the electrode plane showed no significant difference (5.38 for 300 ns shocks and 6.29 for 10 ms shocks, p = 0.22).ConclusionsIn Langendorff-perfused rabbit hearts, nanosecond defibrillation has a similar safety factor as millisecond defibrillation, between 5 and 9, suggesting that nanosecond defibrillation can be performed safely.
Highlights
The delivery of intense electric shocks has for decades been the principal life-saving intervention to terminate ventricular fibrillation
Propidium iodide (PI) staining at the surface of the heart showed that nanosecond shocks had a slightly lower safety factor (6.50) than millisecond shocks (8.69), p = 0.02; while PI staining cross-sections in the electrode plane showed no significant difference (5.38 for 300 ns shocks and 6.29 for 10 ms shocks, p = 0.22)
We showed that single defibrillation-strength shocks caused neither PI uptake nor tissue death and that the only immediate electrophysiological effect was a prolongation of the diastolic interval directly following the shock
Summary
The delivery of intense electric shocks has for decades been the principal life-saving intervention to terminate ventricular fibrillation. Adverse effects of defibrillation may include increased morbidity and mortality, anxiety, pain, and cell damage [1,2,3]. Safety of nanosecond defibrillation they authored a patent for nanosecond defibrillation (US10603503B2/EP3265171A4/ WO2016141096A1), which has been granted in the US and is under consideration at the EP and WIPO. This does not alter our adherence to PLOS ONE policies on sharing data and materials. The search for more efficient yet safer defibrillation has brought the transition from monophasic to biphasic waveforms [4,5,6] and motivates the ongoing research into low-energy defibrillation strategies [7,8,9]
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