Depression, anxiety, and the cardiovascular system: the cardiologist's perspective.

Up to one fifth of patients with cardiovascular disease, including those who have experienced a myocardial infarction, may have concomitant major depression. Studies have suggested that the relative risk of major depression with cardiovascular disease ranges from 1.5 to 4.5. Further information is required to establish a dose-response relationship between depression and coronary artery disease (CAD); however, such a relationship has been shown between anxiety and CAD. Development of a conceptual model of the pathophysiologic actions of stress in CAD will assist in the understanding of this relationship. In patients with angiographic evidence of CAD, the presence of major depressive disorder was the best single predictor of cardiac events during the 12 months following diagnosis. Significantly, 6-month cumulative mortality following diagnosis of myocardial infarction has been shown to be higher in depressed patients than in nondepressed patients. A decrease in heart rate variability may mediate the deleterious effect of depression on post-myocardial infarction prognosis. Other factors such as mental stress and altered platelet function may also predispose depressed patients to a heightened risk of cardiac events. With an increased understanding of the relationship between depression and heightened risk of cardiovascular mortality, it is necessary to assess current overall treatment for cardiac patients.