An implantable medical device has a therapy module configured to generate a composite pacing pulse including a series of at least two individual pulses. The therapy module is configured to generate the composite pacing pulse by generating a first pulse of the at least two individual pulses by selectively coupling a first portion of a plurality of capacitors to an output signal line and generate a second pulse of the at least two individual pulses by selectively coupling a second portion of the plurality of capacitors to the output signal line.