Automated precision current delivery: an alternative method for cardiac defibrillation

Substantial evidence suggests that the current associated with the discharge is a more precise predictor of defibrillation success than is the total energy of the discharge. However, virtually all commercially available defibrillators are calibrated in terms of energy. This article describes an alternative type of experimental defibrillator, which provides a precisely controlled current throughout the discharge waveform, independent of the load presented to the discharge electrodes (or "paddles"). The discharge current waveform is designed to have the classical critically damped sinusoid waveform, identical to that of the traditional energy-based defibrillator when it is properly matched with its ideal load (the heart/thorax combination). The techniques used to obtain a controlled current discharge are discussed in addition to special operational features.