GE MAC 5000

Appendix F – Master’s Step Data: ST-T Change
MAC 5000 System — 2000657-057, Revision B F-5
ST-T Change
The existence of any ST-T change is assessed by classifying
ST-T into three assessment levels: positive, borderline, and
negative. The following criteria is used:
Positive
n ST depression ≥ 0.1mV (2 or more leads).
n ST elevation ≥ 0.2mV (2 or more leads).
n T wave change ≥ 1.0mV (2 or more leads).
u No. 1, 2, or 3 is satisfied.
Borderline
n ST depression ≥ 0.05mV (any leads).
n ST elevation ≥ 0.1mV (any leads).
n T wave change ≥ 0.5mV (any leads).
u No. 1, 2, or 3 is satisfied.
Negative
n Positive and borderline criteria are NOT satisfied.
Calculation
ST depression = (rest ST - post J) - (post exercise ST -
post J)
ST elevation = (post exercise ST - post J) - (rest ST - post J)
T wave change = absolute value of (rest T wave amplitude -
post-exercise T wave amplitude)
(ST - post J: amplitude at the post J point)
When the assessment is positive or borderline, the lead
with the largest change prints.