Comparison Between Silent and Symptomatic Ischemia During Exercise Testing in Patients with Coronary Artery Disease

Abstract

Among 544 patients with proven coronary disease (299 with pathologic coronary arteriograrris and 241 postmyocardial infarction) all of whom had an abnormal treadmill test (ST depression of 1.0–4.0 mm), 253 patients (46.9%) had no angina (silents), whereas 287 (53.1%) had chest pain (symptomatics). Age, sex, previous myocardial infarction, medical therapy, frequency of single vessel and multivessel diseases and the average number of diseased coronary arteries, as well as the heart, rate, blood pressure, and double product at the beginning of the treadmill test and the maximal ST depression, were similar in the silents and the symptomatics. However, in those with silent ischemia, 1 mm ST depression appeared later and at a higher heart rate; they had longer exercise duration, reached higher peak double product, and the postexercise recovery time was shorter than in symptomatic patients. This distinction between “silents” and “symptomatics” was even more pronounced in the analysis of 288 of the patients with an ST depression of only 1.0–1.9 mm (“mildly abnormal” treadmill test). On the other hand, in the 252 patients with ≥2.0 mm ST depression (“strongly abnormal” treadmillt test) this difference disappeared, and all the treadmill variables of the “silents” and the “symptomatics” were found to be similar. It seems, therefore, that if all patients with abnormal treadmill tests are grouped together, irrespective of the degree of ST depression or if only patients with mildly abnormal exercise tests are studied, patients with silent ST depression during exercise testing have milder ischermic parameters during the test than symptomatics. However, according to the similar ischemic parameters observed in the silent and the symptomatic “strongly abnormal” treadmill tests, in such patients the silent and the symptomatic tests express a similar degree of ischemia.