Method and system for compressing and storing data in a medical device having limited storage

The present invention relates to the field of medical devices with limited data storage capacity. More particularly, the present invention relates to implantable devices, such as cardiac pacing systems, that are capable of compressing and storing data, especially cardiac signal data such as episodes of intracardiac electro cardiogram (IEGM). A method for compressing data in an implantable device is provided. A current data sample is received. A difference value is determined between the current data sample and a previous data sample. The current data sample is compressed to at least one output symbol based on the difference value between the current sample and the previous data sample. Systems and programs of using the method are also provided.