Diagnostic value of the recovery time-course of st slope on exercise ECG in discriminating false-from true-positive ST-segment depressions.
BACKGROUND
Using the exercise ECG for diagnosing coronary artery disease (CAD) is hampered by the occurrence of false-positive (FP) ST-segment depression. Because it is known that the recovery ST-T time-course in CAD differs from that in FP subjects, the ST slope may help discriminate FP from true-positive (TP) results.


RESULTS
Treadmill digitized ECG from patients with significant ST-segment depressions and normal resting ECG were analyzed in 134 patients with CAD on angiography (>50% narrowing) and reversible perfusion defects (TP group), and 64 subjects with normal perfusion (FP group) on exercise single photon emission computed tomography. The ST slope between the J-point and J(80) was measured every minute up to 6-min postexercise. The ST slope was significantly higher in FP than in TP at peak exercise, and at postexercise 1-, 2- and 3-min (p<0.01, all). Thereafter, it gradually increased in TP, while monotonically decreasing in FP. Its decrease from 3- to 6-min could correctly diagnose 88% of FP subjects, whereas it was found in only 19% of TP patients (total accuracy 83%).


CONCLUSIONS
The ST slope change from early to late recovery is a simple yet reliable marker for discriminating FP from TP ST-segment responses in subjects with a normal resting ECG.
Division of Cardiology, Department of Medicine, National Cardiovascular Center, Suita, Japan.
Satoru
S
Sakuragi
Hiroshi
H
Takaki
Atsushi
A
Taguchi
Kazuhiro
K
Suyama
Takashi
T
Kurita
Wataru
W
Shimizu
Toru
T
Kawada
Yoshio
Y
Ishida
Tohru
T
Ohe
Kenji
K
Sunagawa
D000368:Aged; D003327:Coronary Disease / Q000175:diagnosis*; D004562:Electrocardiography / Q000379:methods*; D005080:Exercise Test; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged