Ventricular tachycardia and psychiatric depression in patients with coronary artery disease

Selective breeding of rats for high (HAB) and low (LAB) anxiety-related behaviour: A unique model for comorbid depression and social dysfunctions

Animal models of selective breeding for extremes in emotionality are a strong experimental approach to model psychopathologies. They became indispensable in order to increase our understanding of neurobiological, genetic, epigenetic, hormonal, and environmental mechanisms contributing to anxiety disorders and their association with depressive symptoms or social deficits. In the present review, we extensively discuss Wistar rats selectively bred for high (HAB) and low (LAB) anxiety-related behaviour on the elevated plus-maze. After 30 years of breeding, we can confirm the prominent differences between HAB and LAB rats in trait anxiety, which are accompanied by consistent differences in depressive-like, social and cognitive behaviours. We can further confirm a single nucleotide polymorphism in the vasopressin promotor of HAB rats causative for neuropeptide overexpression, and show that low (or high) anxiety and fear levels are unlikely due to visual dysfunctions. Thus, HAB and LAB rats continue to exist as a reliable tool to study the multiple facets underlying the pathology of high trait anxiety and its comorbidity with depression-like behaviour and social dysfunctions.

The Relationship between Depression Symptoms and Severity of Coronary Artery Disease in Patients Undergoing Angiography

Objective: Cardiovascular diseases are the main cause of mortality worldwide. Depression is one of the effective factors in the incidence of cardiovascular diseases like coronary artery stenosis. This study aimed to investigate the relationship between depression symptoms and severity of coronary artery disease (CAD) in patients scheduled for angiography. Method : This prospective, cross sectional research was conducted on as many as 401 patients scheduled to undergo angiography at Dr. Heshmat heart hospital as the referral center in the north of Iran in 2016. Before cardiac catheterization, patients' demographic information (age, gender, level of education, and place of residence) and patients' medical history (history of diabetes mellitus, hypertension, and family history of cardiac disease) were obtained. Also, Beck Depression Questionnaire 2 (BDI II) was completed by a psychologist before angiography. After collecting the data, SPSS v.21 and statistical tests such as Spearman correlation, and Mann-Whitney U regression were used to analyze the data. Results: After controlling for age, sex, and having history of diabetes mellitus, no relation was found between having depression symptoms and more frequency of vessel involvement (OR = 1.35, 95% CI: 0.92 to 1.98, P =0.130) or higher severity of CAD (OR = 1.47, 95% CI: 0.95 to 2.28, P = 0.087). The results were similar for the relation between severity of depression symptoms and CAD extent or CAD severity. Conclusion: The results of this study showed that in patients undergoing angiography, depression symptoms were not related to CAD severity and number of involved vessels. Depression was associated with angina, independently of CAD severity. Our study found no significant correlation between CAD severity and severity of depression. The reason may be that measuring depression at a single time point cannot accurately reveal the impact of this problem on the trend of atherosclerosis over time.

Clinically significant ventricular arrhythmias and progression of depression and anxiety following an acute coronary syndrome

BACKGROUND

Depression and anxiety are common and associated with worse clinical outcomes in patients who experience an acute coronary syndrome (ACS). We investigated the association between major ventricular arrhythmias (VAs) with the progression of depression and anxiety among hospital survivors of an ACS.

METHODS

Patients were interviewed in hospital and by telephone up to 12 months after hospital discharge. The primary outcome was the presence of moderate/severe symptoms of depression and anxiety defined as a Patient Health Questionnaire (PHQ)-9 score ≥ 10 and a Generalized Anxiety Disorder (GAD)-7 score ≥ 10 at baseline and 1 month and PHQ-2 ≥ 3 and GAD-2 ≥ 3 at 3, 6, and 12 months. We used marginal models to examine the association between major VAs and the symptoms of depression or anxiety over time.

RESULTS

The average age of the study population (n = 2074) was 61.1 years, 33.5% were women, and 78.3% were white. VAs developed in 105 patients (5.1%). Symptoms of depression and anxiety were present in 22.2% and 23.5% of patients at baseline, respectively, and declined to 14.1% and 12.6%, respectively, at 1-month post-discharge. VAs were not significantly associated with the progression of symptoms of depression (adjusted relative risk [aRR] = 1.29, 95% confidence interval [CI] = 0.94-1.77) and anxiety (aRR = 1.22, 95% CI = 0.86-1.72), or with change in average scores of PHQ-2 and GAD-2 over time, both before and after risk adjustment.

CONCLUSION

The prevalence of symptoms of depression and anxiety was high after an ACS but declined thereafter and may not be associated with the occurrence of major in-hospital VAs.

Depression and Risk of Sudden Cardiac Death and Arrhythmias: A Meta-Analysis

OBJECTIVE

Depression is an independent risk factor for cardiac events and mortality in individuals with or without cardiovascular disease (CVD), although the underlying mechanisms involved in sudden cardiac death (SCD) and arrhythmias remain unclear. This meta-analysis aimed to assess the relationship between depression and risk of SCD and arrhythmias.

METHODS

We systematically searched MEDLINE, Elsevier, and PsycINFO databases for articles (January 1990 to June 2015) describing the correlation of depression ("depressive symptoms," "depression," or "depressive disorder") with SCD or arrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF], or atrial fibrillation [AF]). Data were meta-analyzed with random-effects models.

RESULTS

A total of 17 studies met the inclusion criteria: 4 of SCD (n = 83,659), 8 of VT/VF (n = 4,048), and 5 of AF (n = 31,247). The total sample consisted of 8,533 individuals with and 110,421 individuals without previous CVD. Depression was associated with increased risk of SCD (hazard risk [HR], 1.62; 95% confidence interval [CI], 1.37-1.92; p < .001), VT/VF (HR, 1.47; 95% CI, 1.23-1.76; p < .001) and AF recurrence (HR, 1.88; 95% CI, 1.54-2.30; p < .001). There was no significant association, however, between depression and risk of new-onset AF (HR, 0.96; 95% CI, 0.87-1.04; p = .311).

CONCLUSIONS

Depression (clinical depression and depressive symptoms) is associated with increased risk of SCD, VT/VF, and AF recurrence. These findings suggest that arrhythmias play an important role in the association between depression and increased mortality in individuals with or without CVD. Systematic evaluation and treatment of depression may contribute to the prevention of lethal cardiac events in the general population and in high-risk individuals with CVD.

Is Symptomatic Long QT Syndrome Associated with Depression in Women and Men?

We examined whether long QT syndrome (LQTS) mutation carrier status or symptomatic LQTS are associated with depression, and whether there are sex differences in these potential relationships. The sample comprised 782 participants (252 men). Of the 369 genetically defined LQTS mutation carriers, 169 were symptomatic and 200 were asymptomatic. The control group consisted of 413 unaffected relatives. Depression was assessed using the Beck Depression Inventory-II (BDI-II). No association was found for LQTS mutation carrier status with depression. The multinomial logistic regression showed that LQTS mutation carrier men with arrhythmic events scored higher on depression compared with the control group, even when adjusting for age, β-blockers, antidepressants, and social support (OR = 1.09, 95 % CI [1.02, 1.15], p = .007). The binary logistic regression comparing symptomatic and asymptomatic LQTS mutation carriers showed that symptomatic LQTS was associated with depression in men (OR = 1.10, 95 % CI [1.03, 1.19], p = .009). The results were unchanged when additionally adjusted for education. These findings suggest that symptomatic LQTS is associated with depression in men but not in women. Overall, however, depression is more frequent in women than men. Thus, regular screening for depression in LQTS mutation carriers and their unaffected family members can be important.

Insufficient glucocorticoid signaling and elevated inflammation in coronary heart disease patients with comorbid depression

Coronary heart disease (CHD) and depression are very common and often co-existing disorders. In addition to psychological and social morbidity, depression exacerbates adverse cardiac outcomes in CHD patients. Inflammation has been proposed as one of the mechanisms involved in the association between these two debilitating diseases. Therefore, the present study aimed to evaluate inflammatory responses as well as to investigate the pathophysiological mechanisms underlying the putative inflammatory activation in CHD patients with and without depression, by assessing the function of two important biological factors regulating inflammation, the hypothalamus-pituitary-adrenal (HPA) axis and the glucocorticoid receptor (GR). Eighty-three CHD patients with (n=28) and without (n=55) comorbid depression were recruited from primary care services in South London. Depression status was assessed by means of Clinical Interview Schedule Revised for diagnosis of depression, and Beck Depression Inventory for the presence of depressive symptoms. Serum C-reactive protein (CRP), plasma vascular endothelial growth factor (VEGF), and plasma and salivary cortisol were measured using commercially available ELISA kits. Gene expression of GR and interleukin-6 (IL-6) were conducted via qPCR. GR sensitivity was evaluated in vitro in isolated peripheral blood mononuclear cells using the dexamethasone inhibition of lipopolysaccharide-stimulated IL-6 levels. Serum levels of kynurenine pathway metabolites were measured using high performance liquid chromatography. Our results show that CHD patients with depression had higher levels of CRP, IL-6 gene expression, and VEGF compared with CHD non-depressed, as well as lower plasma and saliva cortisol levels. The CHD depressed group also exhibited a reduction in GR expression and sensitivity. Finally, tryptophan levels were significantly lower in patients with depression, who also showed an increased kynurenine/tryptophan ratio. In conclusion, CHD patients with depression had elevated levels of inflammation in the context of HPA axis hypoactivity, GR resistance, and increased activation of the kynurenine pathway. Reduced cortisol bioavailability and attenuated glucocorticoid responsiveness due to decreased expression and sensitivity of GR may lead to insufficient glucocorticoid signaling and thus elevation of inflammation in these patients.

Association of depressive and anxiety symptoms with 24-hour urinary catecholamines in individuals with untreated high blood pressure

OBJECTIVE

Depression and anxiety are considered risk factors for cardiovascular disease (CVD). The explanatory mechanisms, however, are still to be characterized. One proposed pathophysiological pathway is dysregulation of the autonomic nervous system, including heightened sympathetic nervous system activity. This study examined the relationship between symptoms of depression, anxiety, and sympathetic nervous system activity in individuals with untreated high blood pressure.

METHODS

A total of 140 participants with untreated high blood pressure (55% white, 38.5% female, mean [standard deviation] age = 45.5 [8.55] years) collected urine over a 24-hour period on 3 separate occasions. Urine samples were assayed for mean 24-hour epinephrine (EPI24) and norepinephrine excretion. Depressive symptoms were assessed using the Beck Depression Inventory, with anxiety symptoms assessed using the Spielberger State-Trait Anxiety Inventory.

RESULTS

Depression and anxiety scores were intercorrelated (r = 0.76, p < .001). EPI24 was positively correlated with anxiety (r = 0.20, p = .02) but not depression (r = 0.02, p = .77), whereas 24-hour urinary norepinephrine excretion was not correlated with anxiety (r = 0.10, p = .21) or with depression (r = 0.07, p = .39). Regression models, accounting for sex, age, body mass index, race, mean systolic ambulatory blood pressure, tobacco use, alcohol use, physical activity, and sleep efficiency confirmed that anxiety was associated with EPI24 excretion (p = .023) and that depressive symptoms were not (p = .54).

CONCLUSIONS

Anxiety was associated with heightened sympathoadrenal activity, suggesting a biological pathway through which anxiety could increase CVD risk. Anxiety and depression may confer increased CVD risk via different mechanisms.

Stress vulnerability during adolescence: comparison of chronic stressors in adolescent and adult rats

OBJECTIVE

This study investigated the physiological and somatic changes evoked by daily exposure to the same type of stressor (homotypic) or different aversive stressor stimuli (heterotypic) in adolescent and adult rats, with a focus on cardiovascular function. The long-term effects of stress exposure during adolescence were also investigated longitudinally.

METHODS

Male Wistar rats were exposed to repeated restraint stress (RRS, homotypic) or chronic variable stress (CVS, heterotypic).

RESULTS

Adrenal hypertrophy, thymus involution, and elevated plasma glucocorticoid were observed only in adolescent animals, whereas reduction in body weight was caused by both stress regimens in adults. CVS increased mean arterial pressure (adolescent: p = .001; adult: p = .005) and heart rate (HR; adolescent: p = .020; adult: p = .011) regardless of the age, whereas RRS increased blood pressure selectively in adults (p = .001). Rest tachycardia evoked by CVS was associated with increased cardiac sympathetic activity in adults, whereas a decreased cardiac parasympathetic activity was observed in adolescent animals. Changes in cardiovascular function and cardiac autonomic activity evoked by both CVS and RRS were followed by alterations in baroreflex activity and vascular reactivity to vasoconstrictor and vasodilator agents in adolescent adult animals. Except for the circulating glucocorticoid change, all alterations observed during adolescence were reversed in adulthood.

CONCLUSIONS

These findings suggest a stress vulnerability of adolescents to somatic and neuroendocrine effects regardless of stress regimen. Our results indicated an age-stress type-specific influence in stress-evoked cardiovascular/autonomic changes. Data suggest minimal consequences in adulthood of stress during adolescence.

Mind and body: how the health of the body impacts on neuropsychiatry

It has long been established in traditional forms of medicine and in anecdotal knowledge that the health of the body and the mind are inextricably linked. Strong and continually developing evidence now suggests a link between disorders which involve Hypothalamic-Pituitary-Adrenal axis (HPA) dysregulation and the risk of developing psychiatric disease. For instance, adverse or excessive responses to stressful experiences are built into the diagnostic criteria for several psychiatric disorders, including depression and anxiety disorders. Interestingly, peripheral disorders such as metabolic disorders and cardiovascular diseases are also associated with HPA changes. Furthermore, many other systemic disorders associated with a higher incidence of psychiatric disease involve a significant inflammatory component. In fact, inflammatory and endocrine pathways seem to interact in both the periphery and the central nervous system (CNS) to potentiate states of psychiatric dysfunction. This review synthesizes clinical and animal data looking at interactions between peripheral and central factors, developing an understanding at the molecular and cellular level of how processes in the entire body can impact on mental state and psychiatric health.

Untreated preoperative depression is not associated with postoperative arrhythmias in CABG patients

PURPOSE

The mechanism by which depression affects postoperative outcome may involve arrhythmias. The purpose of this study was to evaluate whether untreated depression is associated with an increased incidence of postoperative arrhythmias in patients undergoing coronary artery bypass graft surgery (CABG).

METHODS

One hundred seven patients were assessed for signs of depression with the Prime-MD Patient Health Questionnaire (brief PHQ) one week before surgery and subsequently underwent Holter monitoring for 48-72 hr postoperatively. The incidences of atrial fibrillation (AF); supraventricular tachycardia (SVT); ventricular tachycardia (VT), defined as three or more consecutive beats at a cycle length less than 600 msec; ventricular fibrillation (VF); and average heart rate (HR) were recorded in patients with and without signs of depression.

RESULTS

The incidence of preoperative untreated depression was 27% (29/107). Twenty patients had mild depression (brief PHQ score of 5-9), seven patients had moderate depression (a score of 10-14), and two patients had severe depression (a score of 20). The incidences of postoperative AF, SVT, and non-sustained VT in depressed and non-depressed patients were 37.9% vs 35.9%, respectively (P = 0.50), 34.4% vs 52.5%, respectively (P = 0.07), and 17.2% vs 37.1%, respectively (P = 0.04). The average (SD) postoperative HR was similar in both groups [95 (12) beats·min(-1) in depressed patients and 92 (10) beats·min(-1) in non-depressed patients, (P = 0.25)]. Multivariate regression analysis showed that older age, but not depression, was a risk factor for postoperative arrhythmia.

CONCLUSIONS

Preoperative untreated depression is not related to postoperative arrhythmia in the early postoperative period in patients undergoing elective CABG. This trial was registered at clinicaltrials.gov (number: NCT00622024).

Age differences in the association of severe psychological distress and behavioral factors with heart disease

Few studies have examined the risk factors of serious psychological distress (SPD) and behavioral factors for heart disease separately stratified as young (18-44 years), middle aged (45-64 years), and elderly (65 years or older). A total of 3,540 adults with heart disease and 37,703 controls were selected from the 2005 California Health Interview Survey. Data were weighted to be representative and adjusted for potential undercoverage and nonresponse biases. Multiple logistic regression models were used to estimate the associations of the factors with heart disease at different ages. The prevalence of SPD was 8% in cases and 4% in controls, respectively. For young adults, SPD and higher federal poverty level (FPL) were associated with an increased risk of heart disease while for middle-aged adults, SPD, past smoking, lack of physical activity, obesity, male, and unemployment were associated with an increased risk of heart disease. In addition, SPD, past smoking, lack of physical activity, obesity, male, unemployment, White, and lower FPL were associated with an increased risk of heart disease in elderly. Our findings indicate that risk factors for heart disease vary across all ages. Intervention strategies that target risk reduction of heart disease may be tailored accordingly.

Relationship between premature ventricular complexes and depressive symptoms in non-ST-elevation acute coronary syndrome

AIMS

Depression is a recognized risk marker for mortality among acute coronary syndrome (ACS) patients. We hypothesized that ventricular arrhythmia detected by inpatient telemetry monitoring is more frequent among ACS patients with elevated depressive symptoms compared to those without depressive symptoms.

METHODS AND RESULTS

We analysed data from patients enrolled in a prospective observational study of depression in ACS. Telemetry recordings during the index admission (average recording 21.3±3.0 hours) were analysed for frequent premature ventricular complexes (PVCs), defined as ≥10 per hour. The self-report Beck Depression Inventory (BDI) was used to assess depressive symptoms. Among 200 ACS patients, frequent PVCs were observed in 29% of patients with moderate depressive symptoms (BDI ≥10), 27% of those with mild symptoms (BDI 5-9), and only 11% of those with no/minimal symptoms (p=0.02). Log-transformed PVCs per hour were associated with depressive symptom category (p=0.008). In a multivariable logistic regression model that included age, gender, left ventricular ejection fraction, cardiovascular risk score, heart rate, and QT interval, mild symptoms (OR 3.02, 95% 0.97-9.43, p=0.058) and moderate-severe symptoms (OR 3.94, 95% CI 1.27-12.22, p=0.018) were associated with frequent PVCs.

CONCLUSIONS

In this sample of ACS patients, depressive symptoms were independently associated with frequent PVCs during inpatient telemetry monitoring.

Evidence for transcriptional factor dysregulation in the dorsal raphe nucleus of patients with major depressive disorder

Extensive evidence implicates dysfunction in serotonin (5-HT) signaling in the etiology of major depressive disorder (MDD). Dorsal raphe nucleus (DR) is a major source of serotonin in the brain, and previous studies have reported within it alterations in 5-HT-related gene expression, protein levels, receptor binding, and morphological organization in mood disorders. In the present study, we utilized in situ hybridization-guided laser capture microdissection to harvest tissue samples from the middle-caudal subregion of the human DR post-mortem from MDD patients and from psychiatrically normal comparison subjects. Extracted RNA was prepared for gene expression profiling, and subsequent confirmation of select targets with quantitative real-time PCR. Our data indicate expression changes in functional gene families that regulate: (1) cellular stress and energy balance, (2) intracellular signaling and transcriptional regulation, and (3) cell proliferation and connectivity. The greatest changes in expression were observed among transcriptional regulators, including downregulation in the expression of TOB1, EGR1, and NR4A2 and their downstream targets. Previous studies have implicated these gene products in the regulation of functional domains impacted by MDD, including cognitive function, affective regulation, and emotional memory formation. These observations indicate altered function of several transcriptional regulators and their downstream targets, which may lead to the dysregulation of multiple cellular functions that contribute to the pathophysiology of MDD. Future studies will require single cell analyses in the DR to determine potential impact of these changes on its cellular functions and related circuits.

Neuroplasticity in mood disorders

Neuroimaging and neuropathological studies of major depressive disorder (MDD) and bipolar disorder (BD) have identified abnormalities of brain structure in areas of the prefrontal cortex, amygdala, striatum, hippocampus, parahippocampal gyrus, and raphe nucleus. These structural imaging abnormalities persist across illness episodes, and preliminary evidence suggests they may in some cases arise prior to the onset of depressive episodes in subjects at high familial risk for MDD. In other cases, the magnitude of abnormality is reportedly correlated with time spent depressed. Postmortem histopathological studies of these regions have shown abnormal reductions of synaptic markers and glial cells, and, in rare cases, reductions in neurons in MDD and BD. Many of the regions affected by these structural abnormalities show increased glucose metabolism during depressive episodes. Because the glucose metabolic signal is dominated by glutamatergic transmission, these data support other evidence that excitatory amino acid transmission is elevated in limbic-cortical-striatal-pallidal-thalamic circuits during depression. Some of the subject samples in which these metabolic abnormalities have been demonstrated were also shown to manifest abnormally elevated stressed plasma cortisol levels. The co-occurrence of increased glutamatergic transmission and Cortisol hypersecretion raises the possibility that the gray matter volumetric reductions in these depressed subjects are partly accounted for by processes homologous to the dendritic atrophy induced by chronic stress in adult rodents, which depends upon interactions between elevated glucocorticoid secretion and N-meihyl-D-aspartate (NMDA)-glutamate receptor stimulation. Some mood-stabilizing and antidepressant drugs that exert neurotrophic effects in rodents appear to reverse or attenuate the gray matter volume abnormalities in humans with mood disorders. These neurotrophic effects may be integrally related to the therapeutic effects of such agents, because the regions affected by structural abnormalities in mood disorders are known to play major roles in modulating the endocrine, autonomic, behavioral, and emotional experiential responses to stressors.

The integration of depressive behaviors and cardiac dysfunction during an operational measure of depression: investigating the role of negative social experiences in an animal model

OBJECTIVE

There is a bidirectional association between depression and cardiovascular disease. The neurobiological mechanisms underlying this association may involve an inability to cope with disrupted social bonds. This study investigated in an animal model the integration of depressive behaviors and cardiac dysfunction after a disrupted social bond and during an operational measure of depression, relative to the protective effects of intact social bonds.

METHODS

Depressive behaviors in the forced swim test and continuous electrocardiographic parameters were measured in 14 adult, female socially monogamous prairie voles (rodents), after 4 weeks of social pairing or isolation.

RESULTS

After social isolation, animals exhibited (all values are mean ± standard error of the mean; isolated versus paired, respectively) increased heart rate (416 ± 14 versus 370 ± 14 bpm, p < .05) and reduced heart rate variability (3.3 ± 0.2 versus 3.9 ± 0.2 ln(ms(2))). During the forced swim test, isolated animals exhibited greater helpless behavior (immobility = 106 ± 11 versus 63 ± 11 seconds, p < .05), increased heart rate (530 ± 22 versus 447 ± 15 bpm, p < .05), reduced heart rate variability (1.8 ± 0.4 versus 2.7 ± 0.2 ln(ms(2)), p < .05), and increased arrhythmias (arrhythmic burden score = 181 ± 46 versus 28 ± 12, p < .05).

CONCLUSIONS

The display of depressive behaviors during an operational measure of depression is coupled with increased heart rate, reduced heart rate variability, and increased arrhythmias, indicative of dysfunctional behavioral and physiological stress coping abilities as a function of social isolation. In contrast, social pairing with a sibling is behaviorally protective and cardioprotective. The present results can provide insight into a possible social mechanism underlying the association between depression and cardiovascular disease in humans.

Global Psychological Distress and Risk of Atrial Fibrillation Among Women: The Women's Health Study

Background

Symptoms of psychological distress and depression have been associated with risk of ventricular arrhythmias and sudden cardiac death. Their relationship with atrial arrhythmias, however, is less well studied.

Methods and Results

We sought to assess the long-term relations between psychological distress and risk of atrial fibrillation (AF) in the Women's Health Study of female health professionals. We measured psychological symptoms with the Mental Health Inventory-5. Incident AF was assessed annually and verified through medical records. Among 30 746 women without history of cardiovascular disease or AF, 771 cases of AF occurred during a median follow-up of 125 months (interquartile range, 117–130 months). Global psychological distress was not associated with AF risk in age-stratified (P=0.61 for linear trend) or multivariable proportional-hazards models that included antidepressant use (P=0.34). A proxy measure for depression, consisting of Mental Health Inventory-5 score <53, antidepressant use, or both, was also not associated with AF risk in multivariable models (hazard ratio=0.99; 95% confidence interval, 0.78–1.25; P=0.93). In post hoc analyses of individual symptoms from the Mental Health Inventory-5, positive affect, “feeling happy some/a good bit of the time,” was associated with reduced risk of AF (hazard ratio=0.69; 95% confidence interval, 0.49–0.99; P=0.04); other depressive and anxious symptoms were not.

Conclusions

In this prospective study of women without known cardiovascular disease, global psychological distress and specific depressive symptoms were unrelated to AF risk. (J Am Heart Assoc. 2012;1:e001107 doi: 10.1161/JAHA.112.001107.)

Depression and the heart

Cardio Vascular disease (CVD) as well as depression are both highly prevalent disorders and both of them cause a significant decrease in quality of life and increase the economic burden for the patient. Depressed individuals are more likely to develop angina, fatal or non-fatal myocardial infarction, than those who are not depressed. Over the past decade, evidence has accumulated to suggest that depression may be a risk factor for cardiac mortality in patients with established coronary artery disease (CAD). The 'vicious cycle' linking CVD to major depression and depression to CVD, deserves greater attention from both cardio-vascular and psychiatric investigators.(1).

Depression and cardiac disease: a review

Depression is highly prevalent in cardiac patients, with 20% to 40% of patients meeting criteria for major depressive disorder or experiencing an elevation in depressive symptoms. These depressive symptoms are often chronic and persistent, and they have been associated with the development and progression of coronary artery disease, worse health-related quality of life, poor physical functioning, recurrent cardiac events, and a 2- to 2.5-fold increased risk of mortality. Impaired adherence to health behaviors and adverse physiological effects of depression, including inflammation, endothelial dysfunction, platelet hyperactivity, and autonomic nervous system abnormalities, may link depression with adverse cardiac outcomes. Pharmacologic and psychotherapeutic interventions appear to be safe and effective at reducing depressive symptoms in patients with cardiovascular disease and may impact cardiac outcomes. Unfortunately, depression often is unrecognized and untreated in this population, despite the availability of brief screening tools that can be used for this purpose. We recommend the routine screening of cardiac patients for depression when there are adequate mechanisms for management and referral, such as available consulting psychiatrists or care management programs that facilitate the delivery of pharmacologic and psychotherapeutic treatments in this vulnerable population.

A topographical map of the causal network of mechanisms underlying the relationship between major depressive disorder and coronary heart disease

OBJECTIVE

Major depressive disorder (MDD) and coronary heart disease (CHD) are both clinically important public health problems. Depression is linked with a higher incidence of ischaemic cardiac events and MDD is more prevalent in patients with CHD. No single comprehensive model has yet described the causal mechanisms linking MDD to CHD. Several key mechanisms have been put forward, comprising behavioural mechanisms, genetic mechanisms, dysregulation of immune mechanisms, coagulation abnormalities and vascular endothelial dysfunction, polyunsaturated omega-3 free fatty acid deficiency, and autonomic mechanisms. It has been suggested that these mechanisms form a network, which links MDD and CHD. The aim of this review is to examine the causal mechanisms underlying the relationship between MDD and CHD, with the aim of constructing a topological map of the causal network which describes the relationship between MDD and CHD.

METHODS

The search term 'depression and heart disease' was entered into an electronic multiple database search engine. Abstracts were screened for relevance and individually selected articles were collated.

RESULTS

This review introduces the first topological map of the causal network which describes the relationship between MDD and CHD.

CONCLUSIONS

Viewing the causal pathways as an interdependent network presents a new paradigm in this field and provides fertile ground for further research. The causal network can be studied using the methodology of systems biology, which is briefly introduced. Future research should focus on the creation of a more comprehensive topological map of the causal network and the quantification of the activity between each node of the causal network.

The Utility of Animal Models in Understanding Links between Psychosocial Processes and Cardiovascular Health

A bidirectional association between mood disorders and cardiovascular disease has been described; however, the neurobiological mechanisms that underlie this link have not been fully elucidated. The purpose of this review is first to describe some of the important behavioral neurobiological processes that are common to both mood and cardiovascular disorders. Second, this review focuses on the value of conducting research with animal models (primarily rodents) to investigate potential behavioral, physiological, and neural processes involved in the association of mood disorders and cardiovascular disease. In combination with findings from human research, the study of mechanisms underlying mood and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and can promote the development of novel interventions for individuals with these comorbid conditions.

Novelty-evoked activity in open field predicts susceptibility to helpless behavior

Learned helplessness in animals has been used to model disorders such as depression and post-traumatic stress disorder (PTSD), but there is a lack of knowledge concerning which individual behavioral characteristics at baseline can predict helpless behavior after exposure to inescapable stress. The first aim of this study was to determine behavioral predictors of helplessness using the novel and familiar open-field tests, sucrose consumption, and passive harm-avoidance tasks before learned helplessness training and testing. Individual differences in physiologic responses to restraint stress were also assessed. A cluster analysis of escape latencies from helplessness testing supported the division of the sample population of Holtzman rats into approximately 50% helpless and 50% non-helpless. Linear regression analyses further revealed that increased reactivity to the novel environment, but not general activity or habituation, predicted susceptibility to learned helplessness. During restraint stress there were no mean differences in heart rate, heart rate variability, and plasma corticosterone between helpless and non-helpless rats; however, a lower heart rate during stress was associated with higher activity levels during exploration. Our most important finding was that by using an innocuous screening tool such as the novel and familiar open-field tests, it was possible to identify subjects that were susceptible to learned helplessness.

Impact and clinical management of depression in patients with coronary artery disease

The rates of major adverse coronary events, including recurrent ischemic events and death, in patients with coronary artery disease (CAD) have been shown to be significantly increased in patients with depression. In addition, health care costs are higher and health-related quality of life is lower in depressed patients with CAD. Several pathophysiologic mechanisms have been proposed for the association of increased events seen in this population. Studies have focused on antidepressants (specifically, selective serotonin reuptake inhibitors and mirtazapine), psychotherapy (cognitive behavioral therapy and interpersonal psychotherapy), and a wide range of other nonpharmacologic interventions. Pharmacologic and nonpharmacologic treatments are known to improve depressive symptoms in patients with CAD, but their effects on outcomes such as mortality and hospital admissions remain controversial. If treatment of depression is warranted, strategies should include sertraline or citalopram, with or without cognitive behavioral therapy, based on the known efficacy and safety of the drugs in this population. Nonpharmacologic therapy such as aerobic exercise has been shown to improve not only depression but also cardiovascular health. When selecting an appropriate antidepressant, clinicians should consider their patients' comorbid conditions and the potential for drug interactions, and treatment should be frequently monitored. Screening for depression in patients with cardiac disease should be instituted on a routine basis by using either case-finding or symptom-triggered approaches. Based on the high prevalence of depression and its known adverse effects in patients with CAD, future research is needed to help determine the role of antidepressants and nonpharmacologic strategies in improving outcomes in patients with both comorbidities.

Depression and the cardiovascular system: increasing evidence of a link and therapeutic implications

This review explores the epidemiological evidence for the relationship between depression and cardiovascular disease from a mechanistic standpoint. It is important to examine the biological, behavioral and social mechanisms to improve outcomes for depressed cardiac patients. A number of plausible biobehavioral mechanisms linking depression and cardiovascular disease have been identified. Tricyclic antidepressants have various effects on the cardiovascular system, while selective serotonin reuptake inhibitors are not associated with adverse cardiac effects and should, therefore, be the preferred choice for the treatment of most patients with comorbid depression and cardiovascular disease.

Depression and heart rate variability in patients with coronary heart disease

Depression is common in patients with coronary heart disease (CHD) and is a risk factor for cardiac morbidity and mortality in these patients. Depression is associated with autonomic nervous system dysfunction, which may at least partially explain this increased risk. Low heart rate variability (HRV), which reflects excessive sympathetic and/or inadequate parasympathetic modulation of heart rate, is a strong predictor of mortality in patients with CHD. Most studies-both in patients with stable CHD and in patients with a recent acute coronary event-have found HRV to be lower in depressed patients than in their nondepressed counterparts. This manuscript provides an overview of this literature and concludes that HRV may account for a substantial part of the risk associated with depression in CHD.

The influences of depression and venlafaxine use at therapeutic doses on atrial conduction

Patients with depression have increases risk of cardiac mortality. Overdose with venlafaxine has been accused of supraventricular tachycardia, atrial fibrillation and other cardiac effects. Discontinuous and inhomogeneous propagation of sinus impulses in atrium plays a major role in atrial fibrillation. We aimed to measure the effects of venlafaxine therapy on propagation of sinus impulses reflections in electrocardiography in depression. Eligible 19 participants were outpatients with depression. 75 mg/day dose of venlafaxine was administered to the patients. The patients were asked to complete both Beck Depression and Anxiety Inventories. 17 healthy participants enrolled in the study. The electrocardiography records were obtained while patients were drug naive and one week after treatment. The baseline durations of P(minimum) and P(maximum) in the patient group were significantly shorter than controls (p < 0,05). The differences between baseline and after venlafaxine therapy among electrocardiographical variables were statistically insignificant. There were no significant correlations between age, sex, body mass index, clinical inventories and electrocardiographical variables in both patients and controls. Autonomic dysregulation in myocardium is still inconclusive in depression. Venlafaxine at therapeutic dose of 75 mg/day does not seem to be associated with myocardial conduction dysregulation.

Stress, depression, and coronary artery disease: modeling comorbidity in female primates

Depression and coronary heart disease (CHD) are leading contributors to disease burden in women. CHD and depression are comorbid; whether they have common etiology or depression causes CHD is unclear. The underlying pathology of CHD, coronary artery atherosclerosis (CAA), is present decades before CHD, and the temporal relationship between depression and CAA is unclear. The evidence of involvement of depression in early CAA in cynomolgus monkeys, an established model of CAA and depression, is summarized. Like people, monkeys may respond to the stress of low social status with depressive behavior accompanied by perturbations in hypothalamic-pituitary-adrenal (HPA), autonomic nervous system, lipid metabolism, ovarian, and neural serotonergic system function, all of which are associated with exacerbated CAA. The primate data are consistent with the hypothesis that depression may cause CAA, and also with the hypothesis that CAA and depression may be the result of social stress. More study is needed to discriminate between these two possibilities. The primate data paint a compelling picture of depression as a whole-body disease.

Stress, depression and cardiovascular dysregulation: a review of neurobiological mechanisms and the integration of research from preclinical disease models

Bidirectional associations between mood disorders and cardiovascular diseases are extensively documented. However, the precise physiological and biochemical mechanisms that underlie such relationships are not well understood. This review focuses on the neurobiological processes and mediators that are common to both mood and cardiovascular disorders. The discussion places an emphasis on the role of exogenous stressors in addition to: (a) neuroendocrine and neurohumoral changes involving dysfunction of the hypothalamic-pituitary-adrenal axis and the activation of the renin-angiotensin-aldosterone system, (b) immune alterations including activation of pro-inflammatory cytokines, (c) autonomic and cardiovascular dysregulation including increased sympathetic drive, withdrawal of parasympathetic tone, cardiac rate and rhythm disturbances, and altered baroreceptor reflex function, (d) central neurotransmitter system dysfunction involving the dopamine, norepinephrine and serotonin systems, and (e) behavioral changes including fatigue and physical inactivity. The review also discusses experimental investigations using preclinical disease models to elucidate the neurobiological mechanisms underlying the link between mood disorders and cardiovascular disease. These include: (a) the chronic mild stress model of depression, (b) a model of congestive heart failure, (c) a model of cardiovascular deconditioning, (d) pharmacological manipulations of body fluid and sodium balance, and (e) pharmacological manipulations of the central serotonergic system. In combination with an extensive human research literature, the investigation of mechanisms underlying mood and cardiovascular regulation using animal models will enhance understanding the association between depression and cardiovascular disease. This will ultimately promote the development of better treatments and interventions for individuals with co-morbid psychological and somatic pathologies.

Mechanisms underlying altered mood and cardiovascular dysfunction: the value of neurobiological and behavioral research with animal models

A bidirectional association between mood disorders and cardiovascular diseases has been described in humans, yet the precise neurobiological mechanisms that underlie this association are not fully understood. This article is focused on neurobiological processes and mediators in mood and cardiovascular disorders, with an emphasis on common mechanisms including stressor reactivity, neuroendocrine and neurohumoral changes, immune alterations, autonomic and cardiovascular dysregulation, and central neurotransmitter and neuropeptide dysfunction. A discussion of the utility of experimental investigations with rodent models, including those in rats and prairie voles (Microtus ochrogaster), is presented. Specific studies using these models are reviewed, focusing on the analysis of behavioral, physiological and neural mechanisms underlying depressive disorders and cardiovascular disease. Considered in combination with studies using human samples, the investigation of mechanisms underlying depressive behaviors and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and will promote the development of improved interventions for individuals with these detrimental disorders.

Is there an association between depression and cardiovascular mortality or sudden death?

The results of many studies and recent meta-analyses strongly suggest that depression is a risk factor for total and cardiovascular mortality, both in the general population and in patients with known heart disease. By contrast, the association between depression and sudden death or cardiac arrest has received little attention. This issue has been investigated in three recent studies; two were carried out in the general population and showed depression to be a independent risk factor for sudden death. The other study was carried out in patients with acute myocardial infarction (AMI); the adjusted relative risk (RR) of sudden death was significantly increased in depressed patients but, after adjustment for dyspnea/fatigue (a common symptom for heart disease and depression), the RR was no longer statistically significant. However, when the cognitive-affective depressive symptoms were examined separately from the somatic ones (dyspnea/fatigue, etc.), there was a clear trend for an association between cognitive-affective symptoms and sudden death. Because a risk factor can be defined as 'independent' only in a multivariate analysis in which variables are dichotomized, the presence of common symptoms between heart disease and depression represents a very difficult problem. However, taken together, the results of studies carried out in the general population and in patients with AMI strongly suggest that depression is a significant risk factor for sudden death.

Psychobiology of depression/distress in congestive heart failure

Heart failure affects millions of Americans and new diagnosis rates are expected to almost triple over the next 30 years as our population ages. Affective disorders including clinical depression and anxiety are common in patients with congestive heart failure. Furthermore, the presence of these disorders significantly impacts quality of life, medical outcomes, and healthcare service utilization. In recent years, the literature has attempted to describe potential pathophysiologic mechanisms relating affective disorders and psychosocial stress to heart failure. Several potential mechanisms have been proposed including autonomic nervous system dysfunction, inflammation, cardiac arrhythmias, and altered platelet function. These mechanisms are reviewed in this article. Additional novel mechanisms such as mental stress-induced myocardial ischemia are also discussed.

Major depressive disorder and comorbid cardiac disease: is there a depressive subtype with greater cardiovascular morbidity? Results from the STAR*D study

The authors conducted exploratory analyses to determine whether specific symptoms of major depressive disorder (MDD) are associated with cardiac disease in 4,041 outpatients at baseline in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. MDD was diagnosed with the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition; depressive symptoms were evaluated with the 30-item Inventory of Depressive Symptomatology, Clinician-Rated; and cardiac disease, with the Cumulative Illness Rating Scale. After adjustments for gender, age, ethnicity, education, and employment status, sympathetic arousal and early-morning insomnia were significantly associated with cardiac disease. Prospective studies are warranted to confirm these results.

Heart Failure in the Oldest Patients: The Impact of Comorbid Conditions

Heart failure (HF) is the leading cause of hospitalization in older adults; it is also an important cause of death and chronic disability. HF in the elderly differs in many respects from HF occurring during middle age; in particular, the diagnosis and treatment of HF in the elderly are often complicated by the presence of multiple cardiac and noncardiac comorbid conditions, many of which have important implications for the care of the older HF patient. This article reviews the effects of common noncardiac comorbidities on the management of HF in older adults and discusses the impact of noncardiac comorbid conditions on clinical outcomes in the geriatric HF patient.

Ventricular ectopy: impact of self-reported stress after myocardial infarction

BACKGROUND

Although psychologic stress has been implicated in the pathogenesis of ventricular arrhythmias, the relationship between self-reported stress and ventricular ectopy has not been evaluated under naturalistic conditions in acute post-myocardial infarction (MI) patients, a group at elevated risk for arrhythmias.

MATERIALS AND METHODS

Diary-reported stress was measured during 24-hour Holter monitoring in 80 patients (52 men and 28 women) approximately 12 weeks after their MI. In addition, state and trait anxiety were measured using the Spielberger State and Trait Anxiety Inventory, which was administered at the beginning of the 24-hour Holter monitoring session. The relationships between diary-reported stress, anxiety, and ventricular ectopy were evaluated.

RESULTS

Mean diary-reported stress was associated with total ventricular ectopy (beta = .29, P = .01). State anxiety was also associated with 24-hour ectopy (beta = .24, P = .04); however, trait anxiety was not significantly associated with ectopy. Temporal analyses of the relationship between stress and ectopy showed that diary-reported stress was associated with an increase in the number of ventricular premature beats occurring in the following hour (beta = .74, P < .0001).

CONCLUSIONS

These findings extend existing evidence linking psychologic factors to ventricular arrhythmias by demonstrating that psychologic stress predicts increased arrhythmic activity during routine daily activities in post-MI patients.

Heart rate turbulence, depression, and survival after acute myocardial infarction

OBJECTIVE

Depression is a risk factor for mortality after acute myocardial infarction (AMI), possibly as a result of altered autonomic nervous system (ANS) modulation of heart rate (HR) and rhythm. The purposes of this study were to determine: a) whether depressed patients are more likely to have an abnormal HR response (i.e., abnormal turbulence) to premature ventricular contractions (VPCs), and b) whether abnormal HR turbulence accounts for the effect of depression on increased mortality after AMI.

METHODS

Ambulatory electrocardiographic data were obtained from 666 (316 depressed, 350 nondepressed) patients with a recent AMI; 498 had VPCs with measurable HR turbulence. Of these, 260 had normal, 152 had equivocal, and 86 had abnormal HR turbulence. Patients were followed for up to 30 (median = 24) months.

RESULTS

Depressed patients were more likely to have abnormal HR turbulence (risk factor adjusted odds ratio = 1.8; 95% confidence interval [CI] = 1.0-3.0; p = .03) and have worse survival (odds ratio = 2.4; 95% CI = 1.2-4.6; p = .02) than nondepressed patients. When HR turbulence was added to the model, the adjusted hazard ratio for depression decreased to 1.9 (95% CI = 0.9-3.8; p = .08), and to 1.6 (95% CI = 0.8-3.4; p = .18) when a measure of HR variability (LnVLF) was added. The hazard was found to differ over time with depression posing little risk for mortality in year 1 but greater risk in years 2 and 3 of the follow up.

CONCLUSION

ANS dysregulation may partially mediate the increased risk for mortality in depressed patients with frequent VPCs after an AMI.

Explicating links between acute coronary syndrome and depression: study design and methods

OBJECTIVE

To describe a regional study seeking to replicate the suggested strong links whereby lifetime and post-coronary infarction depression are associated with a significant increase in mortality and cardiac morbidity, and consider the comparative influence of both depression and anxiety.

METHOD

We detail relevant international studies and describe both the methodology as well as baseline and 1-month data from our study.

RESULTS

Over a 3-year period we recruited 489 subjects admitted to a Sydney cardiac unit with an Acute Coronary Syndrome (ACS), and assessed by a range of cardiac variables and measures of current and lifetime depression. Ninety-eight per cent of the sample were assessed one month after baseline recruitment to establish depression rates. Long-term outcome reviews of mortality and morbidity and hospitalization rates are proceeding. For those subjects who were depressed in the post-ACS period and, even more so for those who had experienced lifetime depression, distinctly higher scores on anxiety variables (and lifetime caseness for anxiety disorders) were established.

CONCLUSIONS

The strong interdependence between anxiety and depression in this sample of patients admitted with an ACS will allow examination of the comparative extent to which expressions of 'depression' and 'anxiety' contribute to post-ACS morbidity.

Effects of paroxetine and venlafaxine XR on heart rate variability in depression

Depressed patients may exhibit reduced heart rate variability (HRV), and antidepressants which block norepinephrine uptake may also lower HRV. This study compared paroxetine (PAR) and venlafaxine XR (VEN-XR) on HRV. Outpatients were randomly assigned to double-blind treatment with PAR up to 40 mg or VEN-XR up to 225 mg daily. HRV measures of parasympathetic control consisted of change in R-R interval during forced 10-second breaths and respiratory sinus arrhythmia (RSA) during paced breathing. Ex vivo estimates of serotonin and norepinephrine transporter occupancy were obtained before and after treatment, as were measures of depression, anxiety, and resilience. Plasma drug concentrations were measured at end point. Forty-nine patients entered treatment; 44 of whom were evaluable (n = 22 per group). Significant within-group reductions were noted in R-R interval variation and in RSA after VEN-XR only. Between-group analyses showed significant group-by-time interaction, with greater reduction in R-R interval variation and in RSA for VEN-XR compared with PAR. Improvement in resiliency correlated significantly with norepinephrine transporter occupancy for VEN-XR. Further comparisons of selective serotonin reuptake inhibitor and serotonin and norepinephrine reuptake inhibitor drugs on HRV are warranted.

Mood disorders in the medically ill: scientific review and recommendations

OBJECTIVE

The purpose of this review is to assess the relationship between mood disorders and development, course, and associated morbidity and mortality of selected medical illnesses, review evidence for treatment, and determine needs in clinical practice and research.

DATA SOURCES

Data were culled from the 2002 Depression and Bipolar Support Alliance Conference proceedings and a literature review addressing prevalence, risk factors, diagnosis, and treatment. This review also considered the experience of primary and specialty care providers, policy analysts, and patient advocates. The review and recommendations reflect the expert opinion of the authors.

STUDY SELECTION/DATA EXTRACTION

Reviews of epidemiology and mechanistic studies were included, as were open-label and randomized, controlled trials on treatment of depression in patients with medical comorbidities. Data on study design, population, and results were extracted for review of evidence that includes tables of prevalence and pharmacological treatment. The effect of depression and bipolar disorder on selected medical comorbidities was assessed, and recommendations for practice, research, and policy were developed.

CONCLUSIONS

A growing body of evidence suggests that biological mechanisms underlie a bidirectional link between mood disorders and many medical illnesses. In addition, there is evidence to suggest that mood disorders affect the course of medical illnesses. Further prospective studies are warranted.

Depression, the autonomic nervous system, and coronary heart disease

Depression is a risk factor for medical morbidity and mortality in patients with coronary heart disease (CHD). Dysregulation of the autonomic nervous system (ANS) may explain why depressed patients are at increased risk. Studies of medically well, depressed psychiatric patients have found elevated levels of plasma catecholamines and other markers of altered ANS function compared with controls. Studies of depressed patients with CHD have also uncovered evidence of ANS dysfunction, including elevated heart rate, low heart rate variability, exaggerated heart rate responses to physical stressors, high variability in ventricular repolarization, and low baroreceptor sensitivity. All of these indicators of ANS dysfunction have been associated with increased risks of mortality and cardiac morbidity in patients with CHD. Further research is needed to determine whether ANS dysfunction mediates the effects of depression on the course and outcome of CHD, and to develop clinical interventions that improve cardiovascular autonomic regulation while relieving depression in patients with CHD.

Depression as a predictor for appropriate shocks among patients with implantable cardioverter-defibrillators

OBJECTIVES

We sought to examine the relationship between symptoms of depression and shock-treated ventricular arrhythmias among implantable cardioverter-defibrillator (ICD) patients.

BACKGROUND

Depression predicts mortality in patients with coronary artery disease (CAD), but whether this is via an increased risk of fatal ventricular arrhythmias is unclear.

METHODS

We prospectively analyzed data on symptoms of depression and risk of ventricular arrhythmia (ventricular tachycardia/ventricular fibrillation [VT/VF]) resulting in ICD discharge in the Triggers of Ventricular Arrhythmias (TOVA) study. Symptoms were assessed by the Center for Epidemiologic Studies-Depression (CES-D) scale. Scores of 16 to 26 and > or =27 represented mild and moderate/severe depression, respectively. The Cox and Anderson-Gill proportional hazards models were used to test for associations among all patients and patients with CAD.

RESULTS

Among 645 patients with baseline assessments, 90 (14%) were mildly depressed and 25 (3.9%) were moderately to severely depressed. Moderate/severe depression was associated with time to first shock for VT/VF (hazard ratio [HR] 3.2, 95% confidence interval [CI] 1.1 to 9.9) and all shocks for VT/VF including recurrent episodes (HR 3.2, 95% CI 1.2 to 8.6). Among the 476 CAD patients, the association with time to first shock (HR 6.4, 95% CI 1.9 to 21.1) and all shocks (HR 8.3, 95% CI 2.9 to 23.3) remained. The risk of shock for VT/VF was associated with depression severity in the total population (p for trend = 0.02) and among patients with CAD (p < 0.01), even after controlling for multiple confounders.

CONCLUSIONS

More severe symptoms of depression predict shocks for VT/VF among ICD patients. The elevated risk of VT/VF among patients with CAD and depression suggests that arrhythmia may contribute significantly to total mortality in this subgroup.

The relationship between depression and cardiovascular disease

Evidence from epidemiological studies has established that depression is a risk factor for the development of cardiovascular disease (CVD) and that the comorbidity of depression with pre-existing CVD worsens the prognosis for sufferers of CVD. Depression has also been associated with other behaviours that impact on CVD, such as medication non-compliance, and an unwillingness to adopt an exercise program, that reduce the likelihood of successful rehabilitation from CVD. Published literature on the current knowledge of the association between depression and CVD is reviewed in this paper.

Why is depression bad for the failing heart? A review of the mechanistic relationship between depression and heart failure

BACKGROUND

Depression is 4 to 5 times as common in heart failure (HF) patients as in the general population, might confer a higher risk of developing HF, and negatively affects prognosis in established HF.

METHODS AND RESULTS

A review was undertaken via Medline (1966-2003) and PsycINFO (1872-2003) searches using the subject headings "depressive disorder" and "heart failure, congestive." Our findings suggest that the link between depression and HF may be due to shared pathophysiology. Depression may augment catecholamine release, arrhythmias, elaboration of proinflammatory cytokines, and platelet activation--processes that may influence prognosis in HF. Depression is also associated with a higher risk of noncompliance and lower levels of social support, which have been shown to worsen prognosis in HF. The impact of pharmacologic or behavioral treatment for depression on physiologic parameters or clinical outcomes in HF remains unclear. Inherent difficulties in recognition of depression in the setting of HF may decrease the likelihood that depressed patients receive the treatment they need.

CONCLUSIONS

Depression is common in HF, may contribute to the development of HF in susceptible populations, and is independently predictive of poor clinical outcomes. Pathophysiologic pathways and psychosocial issues that are shared between the 2 conditions might explain these observations and represent potential therapeutic targets. Vigilant attention to the recognition and treatment of depression in HF patients is warranted.