GE MAC 5000, Operator'S Manual

Page: 218 / 228

MAC 5000 System — 2000657-024, Revision A
Masters’ Step Data: ST-T Change
F-6
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.