A new coronary artery disease index of treadmill exercise electrocardiograms based on the step-up diagnosis method

Treadmill exercise electrpcordiography (ECG) is one of the most common noni nvasive methods for detecting ischemic heart disease. However, this method has problems due to false-positive and false-negative results in a signific ant number of patients. The aim of this study was to determine whether the diagnostic accuracy of treodmill exercise ECG for detecting significant cor onary stenosis can be improved by employing a step-up diagnostic method usi ng multiple diagnostic indicators. We studied 273 consecutive patients (mea n age, 56 +/- 9 years; 190 men and 83 women) without a history of myocardia l infarction who underwent treadmill exercise ECG and coronary angiography for ischemic chest pain. Of these, 146 patients had no significant coronary stenosis, 61 had single-vessel disease, 56 had multivessel disease, and 10 patients had left main truncus disease. A multivariate logistic regression analysis was used to select 3 treadmill exercise electrocardiographic para meters that were independent predictors of the presence or absence of signi ficant coronary stenosis: exercise-induced maximum ST-segment depression, Q T dispersion immediately after exercise, and Athens QRS score. Significant coronary stenosis was diagnosed with a sensitivity of 84% and a specificity of 90% when a step-up diagnostic method using these 3 indicators was emplo yed.. These results were better than those obtained for each indicator alon e (exercise-induced maximum ST-segment depression: sensitivity, 66%, and sp ecificity, 73%; QT dispersion immediately after exercise [greater than or e qual to 60 ms positive]: sensitivity, 76%, and specificity, 86%; and Athens QRS score [less than or equal to5 mm positive]: sensitivity, 72%, and spec ificity, 72%). We conclude that this step-vp diagnostic method, using multi ple diagnostic indicators, is a clinically useful predictor of the presence or absence of significant coronary stenosis. (C) 2001 by Excerpta Medica, Inc.