We have begun to develop a new annotated long term ambulatory ST-T database. The aim of the database a's to be at reference set containing a number of well documented ischemic ST episodes, asis-related non-ischemic ST episodes, episodes of slow ST level drift and mixed episodes to support development and evaluation of detectors capable of accurate differentiation of ischemic and non-ischemic ST events, as well as basic research into mechanisms and dynamics of ischemia. We discuss selection criteria, define the events of interest, and describe the annotation procedure.