The initial biphasic protocol of 120J-150J-200J for the Rectilinear
Biphasic waveform was chosen based on data from a prospective, randomized,
clinical trial (Mittal et al JACC 1999 24:1595-1601) which showed 99% first shock efficacy at 120J, and 100% efficacy at 150J. Based on this data, the 200J shock
represents a safety margin.