Silent myocardial ischemia: Hemodynamic changes during dynamic exercise in patients with proven coronary artery disease despite absence of angina pectoris

Abstract

The hemodynamic changes during exercise occurring in 36 patients with proven coronary artery disease (10 without and 26 with previous myocardial infarction) who tolerated the stress test without angina were analyzed and compared with changes observed in a control group of 36 carefully matched patients whose exercise was limited by angina. All patients were exercised to the same extent, reaching a similar rate-pressure product at the end of the stress test (19,508 +/- 4,828 [SD] versus 19,247 +/- 4,117 beats/min X mm Hg [NS] in the study and control groups without prior infarction, and 19,665 +/- 3,950 versus 17,701 +/- 4,600 beats/min X mm Hg [NS] in the respective groups with infarction). In all groups left ventricular end-diastolic pressure increased from rest to exercise (from 18 +/- 4 to 36 +/- 11 and from 13 +/- 5 to 29 +/- 9 mm Hg, respectively, in the study and control groups without prior infarction and from 17 +/- 7 to 32 +/- 13 and from 19 +/- 7 to 36 +/- 9 mm Hg in the respective groups with prior infarction). Left ventricular ejection fraction decreased (from 59 +/- 7 to 50 +/- 15 and from 60 +/- 4 to 52 +/- 9% in the study and control groups without prior infarction and from 54 +/- 9 to 47 +/- 10 and 55 +/- 9 to 50 +/- 4% in the respective groups with prior infarction). Whereas the changes from rest to exercise were highly significant within each group, no significant differences were noted between the corresponding groups. Regional de novo hypokinesia appeared in all patients without prior infarction and in 25 and 22 patients, respectively, of the groups with prior infarction. Thus, under similar physical stress conditions, comparable hemodynamic changes indicative of ischemia are observed in patients with significant coronary artery lesions with or without previous myocardial infarction irrespective of the occurrence of angina. Therefore, angina pectoris cannot be considered a prerequisite for hemodynamically significant ischemia during exertion.