Active implantable medical devices (IMDs) may be used to treat a variety of symptoms or diseases. For example, an IMD may be used to generate therapeutic electrostimulation for delivery to one or more tissue sites, such as including one or more cardiovascular or neural targets. Such electrostimulation therapy may include one or more of a cardiac pacing therapy, a cardioversion or defibrillation therapy, a neural stimulation therapy that may include an autonomic modulation therapy (AMT), or one or more other electrostimulation therapies.
In generally-available IMDs, electrostimulation may be generated using power supplies or other circuitry dedicated or hardwired for use with a particular electrode combination, therapy mode, or tissue site. Such therapy modes may correspond to using a power supply circuit configured only for operation in a controlled-current mode for neurostimulation or a power supply circuit configured only for operation in a controlled-voltage mode for cardiac pacing. If multiple tissue sites are to be stimulated, such power supply or other circuitry generally includes dedicated power supplies for each lead or electrode configuration corresponding to a respective site. Such generally-available IMDs may provide only limited options regarding available electrode combinations or therapy modes. For example, an IMD configured for current-mode stimulation is generally not reconfigurable to provide voltage-mode stimulation.