Characterization of temporal patterns of transient ischemic ST change episodes during ambulatory ECG monitoring

To test a hypothesis that different physiologic mechanisms might account for different temporal patterns of ST changes, the authors studied records from the European Society of Cardiology ST-T Database. They measured time- and frequency-domain changes of the instantaneous heart rate time series and incidence of arrhythmias associated with ischemic ST changes for two very different temporal patterns of ST change: a group of records containing salvos of ST episodes, and a group of records containing isolated ST episodes. The observations supported the authors´ hypothesis that salvo patterns reflect coronary vasoconstrictions or vasospasms, and that the isolated episodes result from sporadic physical activity.