Exercise test predictors of ambulatory silent ischemia during daily life in stable angina pectoris

The predictive value of several exercise test parameters in identifying stable angina patients at risk of silent myocardial ischemia during daily life were examined. A total of 97 patients with coronary artery disease, stable angina and ambulatory electrocardiographic data were evaluated. Of the 86 patients with a positive exercise test, 39 (group 1) had greater than or equal to 1 episodes of ST-segment depression and 47 (group 2) did not develop ST changes during ambulatory electrocardiographic monitoring. Comparison of the exercise test parameters between the 2 groups revealed early onset of ischemia during exercise tests as the single most significant (p less than 0.0005) predictor of ambulatory silent ischemia. The other exercise test parameters showing significant differences between the 2 groups were the peak exercise heart rate (117 +/- 23 vs 126 +/- 20 beats/min, p less than 0.05) and peak systolic blood pressure (160 +/- 27 vs 176 +/- 27 mm Hg, p less than 0.01), both of which were significantly lower in the group 1 patients. These data were used to derive simple mathematical formulas for calculating the risk of ambulatory silent ischemia. These results demonstrate that stable angina patients at risk of silent ischemia during daily life can be accurately identified by evaluation of selected exercise test parameters.