The aim of this study is to compare the areas of effectiveness of half-sine monophasic and biphasic depolarizing defibrillation pulses in the diagram of energy / phase of fibrillation cycle. The study was carried out on the ten Tusscher-Panfilov 2006 model of the human ventricular myocyte under the influence of simulated fibrillation in the BeatBox simulation environment under the Fedora operating system. The simulation was carried out on a computer under the Windows 10 operating system, the Fedora operating system was implemented in the Oracle VM VirtualBox virtualization environment. The results of computer simulations have shown that the areas of effectiveness for monophasic and biphasic defibrillation pulses are significantly different. In a biphasic pulse, the fraction of a fibrillation cycle at which refractoriness is extended is significantly higher than that of a monophasic pulse at low defibrillation pulse energies. It can be assumed that this provides the energy advantage of a biphasic defibrillation pulse over a monophasic one.

No abstract

The aim of this study is to compare, on the basis of the guaranteed defibrillation hypothesis, the energy efficiency of a trapezoidal defibrillation pulse with fixed rise and fall times with the main types of defibrillation pulses: truncated exponential with the tilt of 50%, rectangular and half-sine. The study was carried out using the ten Tusscher–Panfilov 2006 human ventricular myocyte model subjected to simulated fibrillation in the BeatBox simulation environment. Depolarizing excitation stimuli with a high frequency were used to simulate fibrillation. The results of computer simulation based on the hypothesis of the guaranteed defibrillation showed that defibrillation pulses are energetically efficient (have low values of threshold energy of defibrillation) in a rather narrow range of phase duration values, beyond which a rapid increase in the threshold energy is observed. In terms of energy efficiency, the trapezoidal pulse with the sloping rise and fall is very close to the half-sine one, and at the same time it has a wider range of energetically effective durations. Significantly higher minimum threshold energy of guaranteed defibrillation is a characteristic of rectangular and truncated exponential pulses, while the truncated exponential pulse has a more uniform characteristic in the area of energetically effective durations. From the results obtained, it can be assumed that the maximum duration of the phases of the defibrillation pulse should be limited to the value of no more than 9ms. In this case, the nominal delivered energy at the load impedance of 175Ω should be at least 140J. The possibility of increasing the pulse duration without a significant drop in its energy efficiency will ensure the delivery of more energy in patients with high transthoracic impedance and, accordingly, a greater probability of successful defibrillation. The above will also increase the probability of successful defibrillation in patients with defibrillation electrodes placement errors.