Enhanced evaluation of treadmill tests by means of scoring based on multivariate analysis and its clinical application: A study of 608 patients

Six hundred eight patients being evaluated for chest pain who did not have valvular disease, cardiomyopathy, left ventricular hypertrophy or bundle branch block, and were not receiving digitalis, had treadmill tests and coronary angiograms. In 351, various exercise variables were correlated by multivariate analysis to coronary artery disease (CAD). In men, significant variables were: (1) maximal heart rate achieved <80% of maximal predicted heart rate (Mx PHR), (2) ST-T change ≥1 mm, (3) age ≥55 years and (4) treadmill time (TT) <8 minutes. These variables rated diagnostic scores of 9, 6, 5 and 3, respectively. A score of ≥7 was considered diagnostic of CAD. In a test group of 192 men in which ST-T change was compared with treadmill score, sensitivity was 65 versus 85%, specificity 79 versus 74% and accuracy 69 versus 83%.

In women, maximal heart rate <90% of Mx PHR and TT of <6 minutes were significant, with an accuracy of 75%. Moreover, 89% of incomplete tests and 70% of tests in patients with previous myocardial infarction were also correctly diagnosed, This method allows convenient use of significant exercise variables for clinical purposes with improved results.