Relationship among mental stress–induced ischemi and ischemi during daily life and during exercise: the Psychophysiologic Investigations of Myocardial Ischemi (PIMI) Study

OBJECTIVES The purposes of this database study were to determine: 1) the relationship between mental stress–induced ischemi and ischemi during daily life and during exercise; 2) whether patients who exhibited daily life ischemi experienced greater hemodynamic and catecholamine responses to mental or physical stress than patients who did not exhibit daily life ischemia, and 3) whether patients who experienced daily life ischemi could be identified on the basis of laboratory-induced ischemi using mental or exercise stress testing. BACKGROUND The relationships between mental stress–induced ischemi in the laboratory and ischemi during daily life and during exercise are unclear. METHODS One hundred ninety-six stable patients with documented coronary disease and positive exercise test underwent mental stress testing and bicycle exercise testing. Radionuclide ventriculography and electrocardiographic (ECG) monitoring were performed during the mental stress and bicycle tests. Patients underwent 48 h of ambulatory ECG monitoring. Hemodynamic and catecholamine responses were obtained during mental stress and bicycle tests. RESULTS Ischemi (reversible left ventricular dysfunction or ST segment depression ≥1 mm) developed in 106 of 183 patients (58%) during the mental stress test. There were no significant differences in clinical characteristics of patients with, compared with those without, mental stress–induced ischemia. Patients with mental stress ischemi more often had daily life ischemi than patients without mental stress ischemia, but their exercise tests were similar. Patients with daily life ischemi had higher ejection fraction and cardiac output, and lower systemic vascular resistance during mental stress than patients without daily life ischemia. Blood pressure and catecholamine levels at rest and during the mental stress tests were not different in patients with, compared with those without, daily life ischemia. Patients with daily life ischemi had higher ejection fraction at rest and at peak bicycle exercise compared with patients without daily life ischemia, but there were no other differences in peak hemodynamic or catecholamine responses to exercise. The presence of ST segment depression during routine daily activities was best predicted by ST segment depression during mental or bicycle exercise stress, although ST segment depression was rare during mental stress. CONCLUSIONS Patients with daily life ischemi exhibit heightened generalized response to mental stress. ST segment depression in response to mental or exercise stress is more predictive of ST segment depression during routine daily activities than other laboratory-based ischemic markers. Therapeutic management strategies might therefore focus on patients with these physiologic responses to stress and on whether lessening such responses reduces ischemia.