Distributed by
Rescue Life - User Manual Rev. 3.1
70
Extensive animal and human data with implanted devices demonstrate that biphasic
waveforms offer substantial reductions in defibrillation thresholds and produce less
myocardial dysfunction than monophasic waveforms [1], [2], [3], [4].
The defibrillation efficacy of the 150-J biphasic waveform was superior to that of the
200-J to 360-J conventional escalating-energy monophasic waveforms for 115 patients
who presented with VF [5].
The difference between monophasic and biphasic waveform is qualitatively similar but
varies quantitatively for different parameter values. The fundamental difference is that
first phase of the biphasic pulse acts as a pre-pulse to remove inactivation from the
heart cell, accelerating its recovery, and thereby lowering the activation threshold for
defibrillation prior to second phase of biphasic pulse which is reversed current flow.
ENOUGH ENERGY FOR RESTORING HEART RHYTHM
The Biphasic Truncated Exponential waveform uses lower energy than the Monophasic
waveform. But the lower energy of biphasic shock is more efficient than high energy of
the monophasic shock for defibrillation to restore heart rhythm.