Treadmill score quantifies electrocardiographic response to exercise and improves test accuracy and reproducibility.

SUMMARYWe have developed a sensitive, accurate and highly reproducible treadmill exercise score (TES) that grades the ST-segment (“ischemic”) response to exercise. Instead of using a single value for peak ST depression, our method integrates all ST-amplitude and slope changes that occur during the test, from onset of exercise to the end of recovery. By reflecting not only the depth of ST depression but the manner and time course by which ST changes develop and resolve, TES incorporates data that correlate with severity of coronary artery disease. Exercise ECGs of 70 patients who also had coronary arteriography were analyzed, as well as exercise records of 46 healthy volunteers. Sensitivity, specificity, predictive accuracy and correct classification rate were 85% (50 of 59), 98% (56 of 57), 98% (50 of 51) and 91% (106 of 116), respectively. Use of TES for qualitative interpretation increased sensitivity 10–15% compared with conventional criteria. TES distinguished the group of patients with three-vessel or left main coronary artery disease from those with twovessel (p < 0.002) or one-vessel disease (p < 0.01). These differed from patients with no vessel disease (p < 0.05). TES also varied linearly when compared with angiographically determined coronary scores (p < 0.001, r = 0.71, SEE = 24.2). Thus, the use of TES greatly improves our ability to diagnose and quantify serially the extent of coronary artery disease and improves the accuracy of statistical statements relating to the probability of disease.