Cardiac defibrillation or cardioversion waveform energy control systems employ transvenous ICDs or subcutaneous SICDs for treating cardiac arrhythmias. The systems comprise differentially driven amplifier circuit operational modes to control the delivery of defibrillation or cardioversion electrical shocks, wherein the shock waveforms are constant current, constant voltage, or constant energy. Biphasic arbitrary shock waveforms deliver increasing and or level energy with increasing time as represented by phase 1 ascending ramp, ascending exponential, ascending chopped, ascending stepped, ascending curved, square, rectilinear or level and or any combination of geometric shaped ascending or level waveforms.
