A method and system are provided for tracking ST shift data. The system includes an implantable medical device having an input configured to receive cardiac signals. Each cardiac signal has an associated heart rate and includes a segment of interest. The implantable medical device further includes a processor configured to determine segment variations of the segment of interest in the cardiac signals. The processor determines a heart rate associated with each of the segment variations with each heart rate falling within a corresponding heart rate range. The implantable medical device also includes a memory configured to store a group of histograms for a corresponding group of heart rate ranges. The histograms store distributions for the segment variations within corresponding heart rate ranges.