1. An apparatus comprising: an implantable cardiac function management device including a programmable controller, the programmable controller configured to include a plurality of user-specifiable therapy control parameter sets, wherein a therapy control parameter set is configured to include at least one of a rate response parameter, a tachy detection parameter, and a tachy therapy parameter, and wherein the programmable controller is configured to initiate a switch from a first therapy control parameter set to a second therapy control parameter set upon expiration of a user-configurable time duration; and a remote external interface for the implantable cardiac function management device, configured to be communicatively coupled to the implantable cardiac function management device via a network to a local external interface and via telemetry between the local external interface and the implantable cardiac function management device, the remote external interface comprising: a communication circuit, configured to communicate with the implantable cardiac function management device; and a processor circuit, configured to perform an analysis of physiologic data received from the implantable cardiac function management device in response to operation of the implantable cardiac function management device using a plurality of the therapy control parameter sets, the processor circuit configured to select a particular therapy control parameter set using the analysis, wherein at least one of the implantable medical device or the processor is configured to analyze physiologic data resulting from using the first therapy control parameter set and to generate a search set of candidate values of a therapy parameter for the second therapy parameter set or a subsequent parameter set by reducing a set of possible values to the search set of candidate values according to the analyzed physiological and previous values of the therapy parameter set used to produce the physiologic data.