TABLE OF CONTENTS Franc Jager
In this chapter, we first review ECG ST segment analysis perspectives/goals and current ST segment analysis approaches. Then, we describe automated detection of transient ST change episodes with special attention to reference databases, the problem of correcting the reference ST segment level, and a procedure to detect transient ST change episodes which strictly models human-expert established criteria. We end the chapter with a description of specific performance measures and an evaluation protocol to assess the performance and robustness of ST change detection algorithms and analyzers. Performance comparisons of a few recently developed ST change analyzers are presented. It is assumed that the reader is familiar with the background presented in Chapter 9.
Typically ambulatory ECG data shows wide and significant (> 50 ?V) transient changes in amplitude of the ST segment level which are caused by ischemia, heart rate changes, and a variety of other reasons. The major difficulties in automated ST segment analysis lie in the confounding effects of slow drifts (due to slow diurnal changes), and nonischemic step-shape ST segment shifts which are axis-related (due to shifts of the cardiac electrical axis) or conduction-change related (due to changes in ventricular conduction). These nonischemic changes may be significant, with behavior similar to real transient ischemic or heart rate related ST segment episodes, and complicate manual and automated detection of true ischemic ST episodes. The time-varying ST segment level due to clinically irrelevant nonischemic causes defines the time-varying ST segment...
