Key result
Asymmetric biphasic shocks decreased the energy required for 90% successful defibrillation by approximately 26% compared to monophasic shocks, primarily due to a higher proportion of newly excited tissue through direct activation.
Why the study?
Do biphasic shocks improve the efficiency of terminating reentrant cardiac arrhythmias compared to monophasic shocks in a computational model?
Do biphasic shocks improve the efficiency of terminating reentrant cardiac arrhythmias compared to monophasic shocks in a computational model?
Computational modeling demonstrates that biphasic shocks are approximately 25% more efficient than monophasic shocks for terminating reentrant arrhythmias due to increased direct activation of tissue.
Biphasic shocks may outperform monophasic in tissue models; leaves open clinical translation and optimal waveform selection.
In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one-dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 10(6) simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation.
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Bragard et al. (2013) studied Ventricular fibrillation / Reentrant cardiac arrhythmias (n=4,800,000). Biphasic shocks (symmetric and asymmetric) vs. Monophasic shocks was evaluated on Energy required for 90% probability of successful reentrant dynamics removal (26% decrease in energy). Asymmetric biphasic shocks decreased the energy required for 90% successful defibrillation by approximately 26% compared to monophasic shocks, primarily due to a higher proportion of newly excited tissue through direct activation.
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