Studies of the effects of a quadriphasic truncated exponential defibrillation pulse in a cardiomyocyte model

Data from simulation the responses of cardiomyocytes in a state of simulated fibrillation to a depolarizing and hyperpolarizing four-phase truncated exponential defibrillation pulse were used to make a comparison with an energetically optimal biphasic truncated exponential pulse. The modeling results showed that a four-phase defibrillation pulse with a first phase of duration 6 msec, the remaining phases of duration 4 msec, between-phase pause durations of 2 msec, and a second-phase amplitude coefficient of 0.5 has significantly higher energy efficiency than a biphasic pulse in which the first two phases have the same shape. As compared with the formation of a biphasic truncated exponential pulse, the formation of a four-phase pulse requires only the addition of two more switching cycles of the bridge polarity switch.