Depression is relatively common in patients with ischemic heart disease (IHD) and is associated with increased risk of mortality and morbidity. However, the mechanisms by which depression adversely affects clinical outcomes of patients with IHD are unknown. This study examined the relationship between depression and myocardial ischemia during mental stress testing and during daily living in patients with stable IHD.

The Center for Epidemiological Studies-Depression scale (CES-D) was administered to 135 patients with IHD to evaluate depressive symptoms. Radionuclide ventriculography was used to evaluate the occurrence of left ventricular wall motion abnormality (WMA) during mental stress and exercise testing. Forty-eight-hour ambulatory electrocardiography was used to assess myocardial ischemia during daily living. The mean CES-D score was 8.2 (SD 7.4, range 0-47) with a median of 7. Logistic regression models using restricted cubic splines revealed a curvilinear relation among CES-D scores and the probability of ischemia. For patients with CES-D scores ≤19 (81.5% of study population), a 5-point increment in the CES-D score was associated with roughly a 2-fold increase in the likelihood of ischemia during mental stress. For patients with CES-D scores >19, the relation among scores and ischemia during mental stress tended to be inversely related, but the portion of the sample is very small. Similar patterns of results were noted for CES-D scores and ischemia during daily life.

Patients with mild to moderate depressive symptoms (CES-D scores ≤19) are more likely to exhibit myocardial ischemia during mental stress testing and during daily living. Myocardial ischemia may be one mechanism by which depression increases the risk of mortality and morbidity in patients with IHD. The observed inverse association between higher level of depressive symptoms and ischemic activity needs to be further assessed in large samples.