Heart failure affects more than 5 million Americans [1
] and new diagnosis rates are expected to almost triple over the next 30 years as our population ages [2
]. Affective disorders including clinical depression and anxiety are common in patients with congestive heart failure (CHF). Studies suggest that depression occurs in approximately 40% of patients with CHF [3
]. This greatly exceeds the 2–9% prevalence observed in the normal population [6
]. Though fewer studies have evaluated anxiety disorders in the context of heart failure, available reports suggest that anxiety is also common, occurring in 18–45% of outpatients with heart failure [7
]. The prevalence of anxiety in this population exceeds the rates observed in the general population [6
] and even exceeds the 2–4% prevalence observed in community samples of older adults [9
Furthermore, the presence of these disorders significantly impacts quality of life, medical outcomes, and healthcare service utilization. Several studies have examined the relationship between depression and outcomes in patients with heart failure [4
]. These studies show that depression is the strongest predictor of health status in patients with heart failure [12
]. In fact, depressed patients exhibited lower observed function (walking distance), increased severity of heart failure symptoms, and impaired health-related quality of life [11
]. Decrements in activities of daily living have also been noted [14
]. Other studies suggest that heart failure patients with depression are at increased risk for re-hospitalization [4
] and death [4
] compared to non-depressed heart failure patients.
Weighed against the literature on depression and heart failure, relatively little is known about the relationship between anxiety symptoms and outcomes in heart failure. One study found a univariate association between anxiety and outcomes in patients with heart failure, but failed to show an association after controlling for depression, social isolation, heart failure status, and other potential confounds [15
]. However, the results reported are from a medical intervention trial rather than a prospective observational study. A second study by Jiang and colleagues also failed to find an association between anxiety symptoms and mortality in hospitalized patients with heart failure [16
]. Due to the inconsistent findings, small number of available reports, and the need for additional research the remainder of this review will focus instead on the relationship between depression, stress, and heart failure.
In recent years, the literature has attempted to describe the pathophysiologic mechanisms relating depression and stress to heart failure. Although this literature is small relative to what is known about the relationship between depression, stress, and other types of heart disease, several potential mechanisms have been proposed including: autonomic nervous system dysfunction, inflammation, cardiac arrhythmias, and altered platelet function. These topics are reviewed in this paper. An additional novel mechanism, mental stress-induced myocardial ischemia, is also discussed.