Prognostic value of myocardial perfusion SPECT versus exercise electrocardiography in patients with ST-segment depression on resting electrocardiography.
BACKGROUND
The value of exercise-induced ST-segment depression for the prognostic evaluation of patients with 1 mm of ST depression or greater on the resting electrocardiogram is controversial.


RESULTS
Patients who underwent exercise myocardial perfusion single photon emission computed tomography (MPS) and had resting ST depression of 1 mm or greater with a nondiagnostic exercise electrocardiographic response (n = 1122) were followed up for 3.4 +/- 2.3 years. Those with paced rhythm, pre-excitation, left bundle branch block, or myocardial revascularization within the first 60 days after MPS were excluded. Additional exercise-induced ST-segment depression was considered significant if > or = 2 mm MPS was scored semiquantitatively by use of a 20-segment model of the left ventricle; the percentage of myocardium involved with stress defects (% myo) was derived by normalizing to the maximal possible score of 80. Hard events were defined as nonfatal myocardial infarction or cardiac death. A Cox analysis was used to determine independent predictors of hard events among clinical, exercise, and nuclear variables. Hard event rates increased as a function of % myo for either patients with exercise-induced ST depression (1.4%/y for normal MPS vs 4.1%/y for % myo >10%, P < .03) or those without it (0.7%/y for normal MPS vs 3.0%/y for % myo >10%, P = .0001). Age, diabetes mellitus, shortness of breath as the presenting symptom, and % myo were independent predictors of hard events. Exercise-induced ST depression was predictive of hard events only when it was 3 mm or greater. The presence and extent of perfusion defects, reflected in the % myo, had incremental prognostic value over clinical variables and also over all degrees of exercise-induced ST depression.


CONCLUSIONS
Although MPS effectively risk-stratifies patients with resting ST depression of 1 mm or greater, the prognostic value of exercise-induced ST depression is limited in these patients, with a small added risk when severe (> or = 3 mm).
De Lorenzo
Andrea
A
Department of Imaging, Division of Nuclear Medicine, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.
Hachamovitch
Rory
R
Kang
Xingping
X
Gransar
Heidi
H
Sciammarella
Maria G
MG
Hayes
Sean W
SW
Friedman
John D
JD
Cohen
Ishac
I
Germano
Guido
G
Berman
Daniel S
DS
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000453:epidemiology; D015897:Comorbidity; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000453:epidemiology*; D004562:Electrocardiography / Q000706:statistics & numerical data*; D005080:Exercise Test / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D012146:Rest; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000453:epidemiology*