The effect of resting ST segment depression on the diagnostic characteristics of the exercise treadmill test

OBJECTIVES The aim of this study is to demonstrate the effect of resting ST segment depression on the diagnostic characteristics of the exercise tread mill rest. BACKGROUND Previous studies evaluating the effect of resting ST segment dep ression on the diagnostic characteristics of exercise treadmill test have b een conducted on relatively small patient groups and based only on visual e lectrocardiogram (ECG) analysis. METHODS A retrospective analysis of data collected prospectively was perfor med on consecutive patients referred for evaluation of chest pain. One thou sand two hundred eighty-two patients without a prior myocardial infarction underwent standard exercise treadmill tests followed by coronary angiograph y, with coronary artery disease defined as a 50% narrowing in at least une major epicardial coronary artery. Sensitivity, specificity, predictive accu racy and area under the curve of the receiver operating characteristic (ROC ) plots were calculated for patients with and without resting ST segment de pression as determined by visual or computerized analysis of the baseline E CG. RESULTS Sensitivity of the exercise treadmill test increased in 206 patient s with resting ST segment depression determined by visual ECG analysis comp ared with patients without resting ST segment depression (77 +/- 7% vs. 45 +/- 4%) and specificity decreased (48 +/- 12% vs. 84 +/- 3%). With computer ized analysis, sensitivity of the treadmill test increased in 349 patients with resting ST segment depression compared with patients without resting S T segment depression (71 +/- 6% vs. 42 +/- 4%) and specificity decreased (5 2 +/- 9% vs. 87 +/- 3%) (p < 0.0001 for all comparisons). There was no sign ificant difference in the area under the curve of the ROC plots (0.66-0.69) or the predictive accuracy (62-68%) between the four subgroups. CONCLUSIONS The diagnostic accuracy and high sensitivity of the exercise tr eadmill test in a large cohere of patients with resting ST segment depressi on and no prior myocardial infarction support the initial use of the test f or diagnosis of coronary artery disease. The classification of resting ST s egment depression by method of analysis (visual vs, computerized) did not a ffect the results. (J Am Coll Cardiol 2000;35:1206-11) (C) 2000 by the Amer ican College of Cardiology.