A system for configuring an ambulatory medical device includes a medical device configured to monitor a patient for an occurrence of one or more cardiac events, and a remote computing device. The remote computing device is configured to receive threshold values related to operation of the medical device from, for example, a physician, the threshold values identifying conditions indicative of an occurrence of a cardiac event. The remote computing device can query a master lookup table to determine a lookup code associated with the received threshold values and encode a key including the lookup code. Upon activation of the medical device, the remote computing device can establish a communication link with the medical device and transmit the encoded key to the medical device. The medical device can decode the lookup code, identify the threshold values on a local lookup table, and operate according to the identified threshold values.
