Optimal programming of defibrillation pulses

The optimum pulse is that which can defibrillate with lowest energy. Reduction of energy can be reached two-fold: by looking for a pulse duration with lowest energy threshold and by finding the optimal truncation with lowest refibrillating effect. Assuming that there is also a rheobase in defibrillation, below which no defibrillating, but probably a refibrillating effect exists, the exponential pulse should be truncated if it intersects with the rheobase. Combining the fundamental law of electrostimulation with this boundary condition allows for the solution of the above problem of optimizing energy mathematically. The most important parameter in reaching optimized defibrillation is the output capacitor. The calculations reveal that today´s implantable cardioverter defibrillator devices (ICD) possess refibrillating tilts, that pulse durations should be programmed to values between 4 and 10ms, and that smaller output capacitors would minimize the energy requirements. The ICD of the future should have a programmable output capacitance and should intelligently calculate the best output capacitance and pulse duration combination to achieve lowest possible energy thresholds for a given lead impedance. Whether optimized monophasic pulses are inferior or equal to biphasic pulses needs further experimental studies