An electrotherapy circuit administers to a patient a current waveform. The electrotherapy circuit includes a storage device, at least two discharge electrodes ted by electrical circuitry to opposite poles of the storage device, a resistive circuit connected between charge storage device and one of the electrodes, and a control circuit. The control circuit is connected to the resistive circuit and controls the resistance of the resistive circuit during discharge of the charge storage so as to shape a current waveform produced between the discharge electrodes.