Characterization of transient ischemic and non-ischemic ST segment changes

Using trend plots of heart rate, Karhunen-Loeve coefficient representations of ST segments and QRS complexes, and time-domain measures of ST level and QRS morphology, the authors have studied temporal patterns of ST change episodes and their associations with heart rate changes and arrhythmias in the European Society of Cardiology ST-T Database. The authors describe methods for discriminating between ischemic and non-ischemic ST episodes, and for interpreting mixed ischemic and non-ischemic ST changes as well as long-term drift of ST level. Further, the authors describe distinctly different temporal patterns in ischemic ST episodes, and the association of heart rate changes and arrhythmias with ischemic ST episodes.