Biphasic defibrillators are deliver shock in two directions, from one paddle to the other, then the current reverses direction. Biphasic waveforms decrese the threshold for successful defibrillation. This means biphasic defibrillators are more effective than monophasic defibrillatos and use less electrical energy to defibrillate or cardiovert. Using less electrical energy results in less postshock myocardial dysfunction and a lower risk of skin burns.