A short duration, small capacitor, biphasic waveform has lower defibrillation thresholds than a clinically available biphasic waveform

A biphasic waveform delivered from an 85 uF capacitor was compared to a biphasic waveform delivered from a commercially available implantable defibrillator (ICD). The test waveform had a phase one (O1) duration of 4 ms, a phase two (O2) duration of 2.5 ms, and an innitial O2 voltage equal to the terminal O1 voltage. The control was delivered from a 150 uF capacitor, had adjustable pulse widths (O1, O2 = 8 ms for a 50 ohm load), and an initial O2 voltage equal to 50 por cento of the O1 terminal volge. The short duration, small capacitor waveform reduced stored energy defibrillation thresholds (DFT) by 18 por cento and increased O1 leading edge voltage by 20 por cento when compared to the control.