History, Principle and Techniques for Waveform Optimization in External Defibrillations

Cardiac defibrillation consists of delivering a therapeutic dose of electrical current to the fibrillating heart with the aid of a device named defibrillator. Defibrillation waveform, which is the temporal pattern of its amplitude measured by voltage or current, is one of the principle determinants of defibrillation efficacy. The purpose for the optimization of the waveform is to improve the defibrillation efficacy while decrease the risk of shock induced cardiac injury. The optimization is achieved by adjusting the defibrillation waveform parameters, including voltage, current, pulse duration, tilt, polarity and morphology. This paper reviewed the history, principle and recent techniques on waveform optimization techniques that related to external defibrillation. The patents presented demonstrate the decreased energy requirement, increased efficacy, and self-adjusting optimal waveforms based on the patient parameter measurements. Keywords: Waveform Optimization, Cardiac Arrest, External Defibrillation, Ventricular Fibrillation, Waveform design, Electrical defibrillation, Biphasic defibrillation waveform, Self adjusting optimal waveform, Triphasic waveforms, cardiopulmonary resuscitation, BTE waveform, myocardial injury, Damped biphasic truncated waveform, Rectilinear biphasic waveform