In recent years, AEDs began using biphasic waveform technology, the same technology that is used in implantable defibrillators. Biphasic technology essentially directs energy through the heart in one direction and again in the reverse direction. Usually less energy is required when biphasic waveforms are used. Some devices with biphasic waveforms maintain a constant energy level for all shocks; others use escalating levels of energy. Monophasic Vs Biphasic technology