The effect of defibrillation pulses of different waveforms on the Luo–Rudy cardiomyocyte model in the Cell Electrophysiology Simulation Environment (CESE) was comparatively tested. It was established that a half-sine pulse has the minimum threshold of cell excitation energy, while an exponential pulse exhibits the maximum threshold (22% increase in comparison with the half-sine pulse). The threshold energy of the trapezoidal pulse with sloped rising and falling (waveform of the first phase of bipolar pulse in imPulse AND-P automated external defibrillators at energy levels of 150 and 180 J) was only slightly (4%) higher than the threshold energy of the half-sine pulse. The threshold energy of truncated exponential pulses, which are widely used in modern defibrillators, exceeded the threshold energy of the half-sine pulse by 10-14% (depending on the decline value). These results obtained with the Luo–Rudy model differ significantly from the results obtained using the characteristic energy method with the Blair model.