Wonder if part of what caused him to react more adversely to the shocks is because, as a lean bodybuilder he more conductive than a fatty with padding of insulation. Could be that the current went through his muscular and highly trained nervous system more readily than a normal person and the current went right to his heart. (Nervous system of a bodybuilder would be more responsive than a normal person, since they are asking their muscles to fire over-and-over-and-over many times during frequent workouts.)
This conductivity is the basis for the Bioelectrical Impedence Analysis (BIA) devices that measure your bodyfat. BIA sends a small electrical charge or current through your body and determines the percentage of body fat by measuring the resistance. The determination is based on the fact that muscle, with its high content of water, is more conductive than fat. Thus muscle tends to transmit the current, while fat impedes it.
That being said, I am sure that it was steroids that killed this bodybuilder, just like every other bodybuilder who dies young.