In the exemplary embodiments, the processing circuit for supplying the stimulation pulses comprises a series arrangement of capacitors which are chargeable in parallel and dischargeable serially. The goal of the disclosure, given such a heart pacemaker, is to see to the greatest possible variability of the output amplitude given the lowest possible technical outlay. This goal is inventively achieved in that program switches are allocated to the capacitor circuit for interconnecting or, respectively, disconnecting individual capacitors in combination randomly prescribable as needed for parallel charging and/or serial discharge, said interconnection or, respectively, disconnection occurring according to programs of a program generator.