Construction of Energy-Optimal Smooth Monophasic Defibrillation Pulse Waveforms Using Cardiomyocyte Membrane Model

Abstract

The goal is to help create smooth energy-optimal monophasic pulse waveforms for defibrillation using the Luo-Rudy cardiomyocyte membrane computer model. The waveforms were described with the help of the piecewise linear function. Each line segment provides a transition from one present level of the transmembrane potential to the next with a minimal energy value. The duration of the last segment was defined as a minimum duration at which an action potential occurs. Monophasic waveforms of segments 3, 10 and 29 were built using different increments of the transmembrane potential. The pulse energy efficiency was evaluated according to their threshold energy ratios in mA 2 •ms/cm 4 . There was virtually no difference between the threshold energy ratios of the three waveforms constructed and those of the previously studied energy-optimal halfsine waveform: 241 -242 and 243 mA 2 •ms/cm 4 . The pulse waveform constructed is characterized by a low rise and fall as the duration of the rise is ~1.5 times longer than that of the fall. Conclusion: Energy-optimal smooth monophasic pulse waveforms have the same threshold energy ratio as the optimal half-sine one which was studied before. The latter is equivalent to the first phase of biphasic quasi-sinusoidal Gurvich-Venin pulse which has been used in Russia since 1972. Thus, the use of the Luo-Rudy cardiomyocyte membrane model appears to offer no possibilities for a substantial increase in the energy efficiency (threshold energy ratio reduction) of the classical monophasic defibrillation pulse waveforms.

Study of the Impact of Rectangular Current Pulses on the Ten Tusscher-Panfilov Model of Human Ventricular Myocyte

“…The simulation environment was set up in the Fedora operating system which was installed in the Oracle VM VirtualBox virtualization system on a PC using the Windows 7 operating system. We presented above the rationale for the use of the energy ratio as a parameter indicative of pulse energy efficiency [8]. A rectangular pulse waveform was chosen for the study as it had been described in the BeatBox scripts in elementary terms.…”

“…A number of previous theoretical studies have studied the effect on the cardiomyocyte membrane model of a single excitation pulse [1][2][3][4][5][6][7][8]. However, a study of the impact of an electrical defibrillation pulse on cardiomyocytes should consider the fact that during fibrillation a cardiomyocyte is not in a resting state and is subject to the impact of an abnormally frequent parasitic excitation wave while myocardial cardiomyocytes are in different phases of the excitation cycle.…”