Cardiovascular reactivity and silent ischemia in response to mental stress in symptomatic and asymptomatic coronary artery disease patients: results of a pilot study.

The current study was designed to examine cardiovascular reactivity to psychological tasks and its relationship to provocation of ischemia in asymptomatic coronary artery disease (CAD) patients with documented silent ischemia and those with painful ischemia. ECG, heart rate, and blood pressure responses to mental stress were collected for 13 patients with coronary artery disease (CAD) and for 6 healthy control subjects. Six of the CAD patients were asymptomatic (documented silent ischemia and no history of angina), while the remaining 7 were symptomatic (history of angina). Three types of mental stress were employed: white noise (a passive stressor), digits repeated backwards (an active stressor), and a math task plus white noise (active + passive stressor). Results indicate that significant increases in heart rate and blood pressure, but not silent ischemic episodes, were induced by the mental stress tasks. In addition, patients with documented exercise-induced and ambulant silent ischemia showed trends of blunted autonomic responsiveness to the stressors. On the digits backwards task, the CAD patients with silent ischemia showed significantly lower diastolic blood pressure responses compared with controls or angina patients. Findings suggest that ischemic episodes are not easily induced by brief mental stress. However, results indicate that asymptomatic CAD patients with silent ischemia may be lacking in autonomic responsiveness, particularly in terms of peripheral resistance, to mental stress in comparison with health controls and symptomatic ischemic patients. Further investigation is needed to explore how patients with silent ischemia typically respond autonomically to mental stress and how blunted reactivity may relate to the provocation of unrecognized ischemic episodes.