A patient-worn
energy delivery apparatus for imparting electrical therapy to the body of a patient responsive to an occurrence of a treatable condition includes a
voltage converter for converting electrical energy from an initial
voltage to a final
voltage, and a defibrillator electrically coupled between the converter and the patient and having an energy reservoir for receiving the electrical energy. The defibrillator produces preshaped electrical pulses such as
defibrillation pulses and
cardioversion pulses. The apparatus additionally includes an
energy delivery controller electrically coupled to the patient and the converter and the defibrillator. The controller causes the converter to provide the electrical energy to the defibrillator at a specific charging rate in response to an
energy level in the reservoir. The apparatus may include a plurality of electrodes interposed between the defibrillator and the patient and each
electrode preferably has an impedance reducing means contained therein. One embodiment of the apparatus may include a H-bridge to produce a positive-going pulse segment and the negative-going pulse segment within the biphasic exponential signals. The apparatus periodically measures the energy as it is being delivered to the patient and can pre-emptively stop or truncate the pulse in the event an error condition is detected, such as an
overvoltage condition or if the
energy level approaches a predetermined level. The electrical components which store and release the energy minimize the size and expense of the apparatus, while isolating the
microcomputer from the
high energy levels as the therapeutic pulse is delivered.