Q. What do you mean by ST Hystersis?
Ans.
The rate of recovery of ST depression has been recognized as a measure of ischaemia severity for many years. When comparing the magnitude of ST depression during recovery according to the time, with that just before termination of exercise, it has little discriminatory value. When recovery ST depression is plotted according to heart rate and composed to ST depression during exercise at similar heart rates, the results become more useful. A clockwise plot is common in normal patients who have ST depression, whereas, a counter clockwise plot depicts the ischaemic.