The goals of this project are to investigate the response of mental stress-induced myocardial ischemia (MSIMI) to escitalopram, a selective serotonin reuptake inhibitor (SSRI); to determine whether MSIMI will be reduced by the treatment, and whether the modification of MSIMI is related to improvement of depression symptoms, and/or the reduction of platelet aggregation, and/or the reduction of cardiovascular reactivity. This is a randomized study using escitalopram versus placebo for stable ischemic heart disease patients with MSIMI. This study will also explore the role of platelet activity in occurrence with MSIMI and other characteristics of MSIMI, such as systolic and diastolic function of the left ventricle during mental stress testing as compared to exercise testing.