1. A medical system comprising: an external medical device comprising a video output; and a processor in communication with the video output; and an implantable medical device capable of rate adaptive pacing based on a pacing algorithm, wherein the pacing algorithm includes one or more rate response parameters, the external medical device configured to display information through the video output as a graph, the graph comprising data representing pacing rates of the implantable medical device as a function of activity level over time; the external medical device further configured to accept pacing rate user input through direct manipulation of the graph, wherein the system is configured to calculate changes to one or more rate response parameters of the pacing algorithm in response to pacing rate user input.