Positive exercise test in the absence of pain. Characteristic of a high-risk population?

157 consecutive patients (pts) with suspected coronary artery disease and an ischemic ecg response during exercise test (ET) were studied. During ET 61 of them (group I) had neither chest pain nor anginal equivalent, while 96 (group II) experienced angina. There were no significant differences between the two groups in regard to age, sex, prior myocardial infarction, history of angina or hypertension. During ET pts of group I tolerated a higher work load (group I 3467 Kpm, group II 2594 Kpm, P less than 0,05) and had a higher maximal heart rate (group I 128,3 b/min, group II 120,4 b/min, P less than 0,05) with a more marked ST segment depression (group I 2,4 mm, group II 1,8 mm, P less than 0,01) and with a more elevated incidence of arrhythmias (group I 18%, group II 7%, P less than 0,05). The coronary angiography showed significant obstruction (greater than or equal to 75%) in 91,7% of group I and in 91,6% of group II (prevalence of single vessel disease in group I and multiple vessel disease in group II). No significant difference was found between group I and II in regard to left ventricular ejection fraction (group I 51%, group II 53%), left ventricular end-diastolic pressure (group I 12,9 mmHg group II 13,6 mmHg) and left ventricular end-diastolic volume (group I 102,3 ml/m2, group II 104,2 ml/m2). We conclude that ST segment depression during ET in asymptomatic pts at risk for cardiovascular disease is predictive of coronary artery disease as in symptomatics. These subjects have, compared with symptomatics, a higher work load tolerance but with more marked ecg ischemic changes and more frequent arrhythmias during ET, thus representing a group of coronary population at potentially higher risk.