How do monophasic and biphasic waveforms differ?
Current flow and waveform shape. A monophasic waveform provides current flow between the electrodes in one direction only. For biphasic waveforms, the current flows first one direction, then reverses and flows the other way. Waveform shapes may be damped sine-wave or truncated exponential. See figure 1. Experience. There is a wealth of experience with external defibrillators that employ monophasic waveforms, and the performance outcomes associated with these devices have been well documented in a number of settings. Implantable defibrillators have used biphasic waveforms since the early ’90s, and there is a thorough understanding of the advantages that biphasic waveforms offer in this setting. For external defibrillators, however, biphasic waveforms are a more recent technological evolution, and their therapeutic impact has not yet been fully characterized across the wide range of settings in which these devices may be used. Safety factor, and peak current needed for defibrillation. Fo
