Association of depressive symptoms with reduced baroreflex cardiac control in coronary artery disease

Higher Cardiovagal Baroreflex Sensitivity Predicts Increased Pain Outcomes After Cardiothoracic Surgery

Excessive postoperative pain can lead to extended hospitalization and increased expenses, but factors that predict its severity are still unclear. Baroreceptor function could influence postoperative pain by modulating nociceptive processing and vagal-mediated anti-inflammatory reflexes. To investigate this relationship, we conducted a study with 55 patients undergoing minimally invasive cardiothoracic surgery to evaluate whether cardiovagal baroreflex sensitivity (BRS) can predict postoperative pain. We assessed the spontaneous cardiovagal BRS under resting pain-free conditions before surgery. We estimated postoperative pain outcomes with the Pain, Enjoyment, and General Activity scale and pressure pain thresholds on the first (POD1) and second (POD2) postoperative days and persistent pain 3 and 6 months after hospital discharge. We also measured circulating levels of relevant inflammatory biomarkers (C-reactive protein, albumin, cytokines) at baseline, POD1, and POD2 to assess the contribution of inflammation to the relationship between BRS and postoperative pain. Our mixed-effects model analysis showed a significant main effect of preoperative BRS on postoperative pain (P = .013). Linear regression analysis revealed a significant positive association between preoperative BRS and postoperative pain on POD2, even after adjusting for demographic, surgical, analgesic treatment, and psychological factors. Moreover, preoperative BRS was linked to pain interfering with general activity and enjoyment but not with other pain parameters (pain intensity and pressure pain thresholds). Preoperative BRS had modest associations with postoperative C-reactive protein and IL-10 levels, but they did not mediate its relationship with postoperative pain. These findings indicate that preoperative BRS can independently predict postoperative pain, which could serve as a modifiable criterion for optimizing postoperative pain management. PERSPECTIVE: This article shows that preoperative BRS predicts postoperative pain outcomes independently of the inflammatory response and pain sensitivity to noxious pressure stimulation. These results provide valuable insights into the role of baroreceptors in pain and suggest a helpful tool for improving postoperative pain management.

Baroreflex sensitivity in facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD), a common form of muscular dystrophy, is caused by a genetic mutation that alters DUX4 gene expression. This mutation contributes to significant skeletal muscle loss. Although it is suggested that cardiac muscle may be spared, people with FSHD have demonstrated autonomic dysregulation. It is unknown if baroreflex function, an important regulator of blood pressure (BP), is impaired in people with FSHD. We examined if baroreflex sensitivity (BRS) is blunted in patients with FSHD. Thirty minutes of resting BP, heart rate, and cardiovagal BRS were measured in 13 patients with FSHD (age: 50 ± 13 years, avg ± SD) and 17 sex- and age-matched controls (age: 47 ± 14 years, p > 0.05). People with FSHD were less active (Activity Metabolic Index, AMI) (FSHD: 24 ± 30; controls: 222 ± 175 kcal/day; p < 0.001) but had a similar body mass index compared with controls (FSHD: 27 ± 4; controls: 27 ± 4 kg/m2 ; p > 0.05). BRSup (hypertensive response), BRSdown (hypotensive response), and total BRS were similar between groups (BRSup: FSHD: 12 ± 8; controls: 12 ± 5 ms/mmHg; BRSdown: FSHD: 10 ± 4; controls: 13 ± 6 ms/mmHg; BRS: FSHD: 14 ± 9; controls: 13 ± 6 ms/mmHg; p > 0.05). Mean arterial pressure was similar between groups (FSHD: 96 ± 7; controls: 91 ± 6mmHg). Individuals with FSHD had an elevated heart rate compared with controls (FSHD: 65 ± 8; controls: 59 ± 8 BPM; p = 0.03), but when co-varied for AMI, this relationship disappeared (p = 0.39). These findings suggest that BRS is not attenuated in people with FSHD, but an elevated heart rate may be due to low physical activity levels, a potential consequence of limited mobility.

Chronic mild stress paradigm as a rat model of depression: facts, artifacts, and future perspectives

RATIONALE

The chronic mild stress (CMS) paradigm was first described almost 40 years ago and has become a widely used model in the search for antidepressant drugs for major depression disorder (MDD). It has resulted in the publication of almost 1700 studies in rats alone. Under the original CMS procedure, the expression of an anhedonic response, a key symptom of depression, was seen as an essential feature of both the model and a depressive state. The prolonged exposure of rodents to unpredictable/uncontrollable mild stressors leads to a reduction in the intake of palatable liquids, behavioral despair, locomotor inhibition, anxiety-like changes, and vegetative (somatic) abnormalities. Many of the CMS studies do not report these patterns of behaviors, and they often fail to include consistent molecular, neuroanatomical, and physiological phenotypes of CMS-exposed animals.

OBJECTIVES

To critically review the CMS studies in rats so that conceptual and methodological flaws can be avoided in future studies.

RESULTS

Analysis of the literature supports the validity of the CMS model and its impact on the field. However, further improvements could be achieved by (i) the stratification of animals into 'resilient' and 'susceptible' cohorts within the CMS animals, (ii) the use of more refined protocols in the sucrose test to mitigate physiological and physical artifacts, and (iii) the systematic evaluation of the non-specific effects of CMS and implementation of appropriate adjustments within the behavioral tests.

CONCLUSIONS

We propose methodological revisions and the use of more advanced behavioral tests to refine the rat CMS paradigm, which offers a valuable tool for developing new antidepressant medications.

Depression and anxiety following acute myocardial infarction in women

Cardiovascular disease is the leading global cause of mortality, with ischemic heart disease causing the majority of cardiovascular deaths. Despite this, diagnostic delay commonly occurs in women experiencing acute myocardial infarction (AMI) who have a higher associated in-hospital mortality. Several studies have demonstrated that women are significantly more likely than men to experience depression and anxiety following AMI which is linked with increased morbidity, rehospitalization, and mortality, as well as decreased quality of life. Thus, it is imperative that future work aims to understand the factors that put women at higher risk for depression and anxiety following AMI, informing prevention and intervention. This narrative review will summarize the current literature on the association between AMI and mental health in women, including the impact on morbidity, mortality, and quality of life.

The cardiac, vasomotor, and myocardial branches of the baroreflex in fibromyalgia: Associations with pain, affective impairments, sleep problems, and fatigue

This study investigated the cardiac, vasomotor, and myocardial branches of the baroreflex in fibromyalgia using the spontaneous sequence method. Systolic blood pressure (SBP), interbeat interval (IBI), stroke volume (SV), pre-ejection period (PEP), and total peripheral resistance (TPR) were continuously recorded in 40 fibromyalgia patients and 30 healthy individuals during a cold pressor test and a mental arithmetic task. Sequences of covariation between SBP and IBI (cardiac branch), SV and PEP (myocardial branch), and TPR (vasomotor branch) were identified. Baroreflex sensitivity (BRS) was represented by the slope of the regression line between values in the sequences; baroreflex effectiveness (BEI) was indexed by the proportion of progressive SBP changes that elicited reflex responses. Patients exhibited lower BRS in the three branches, lower BEI in the cardiac and vasomotor branches, and reduced reactivity in cardiac BRS and BEI, SBP, IBI, SV, and PEP. Moreover, BRS and BEI were inversely related to clinical pain, cold pressor pain, depression, trait anxiety, sleep problems, and fatigue. Reduced function of the three baroreflex branches implies diminished resources for autonomic inotropic, chronotropic, and vascular regulation in fibromyalgia. Blunted stress reactivity indicates a limited capacity for autonomic cardiovascular adjustment to situational requirements. The associations of BRS and BEI with pain perception may reflect the antinociceptive effects arising from baroreceptor afferents, where reduced baroreflex function may contribute to the hyperalgesia characterizing fibromyalgia. The associations with affective impairments, sleep problems, and fatigue suggest that baroreflex dysfunctions are also involved in the secondary symptoms of the disorder.

Autonomic Modulation of Cardiac Activity Across Levels of Sleep Depth in Individuals With Depression and Sleep Complaints

OBJECTIVE

We assessed mean heart rate (HR) and HR variability (HRV) across wake, rapid eye movement (REM) sleep, and non-REM (NREM) sleep, and across varying levels of NREM sleep depth in individuals with depression and sleep complaints.

METHODS

Retrospective polysomnographic data were obtained for 25 individuals diagnosed as having depression (84% female; mean age = 33.8 ± 12.2 years) and 31 mentally healthy controls (58.1% female; mean age = 37.2 ± 12.4 years). All were free of psychotropic and cardiovascular medication, cardiovascular disease, and sleep-related breathing disorders. HR and time-domain HRV parameters were computed on 30-second electrocardiography segments and averaged across the night for each stage of sleep and wake.

RESULTS

Compared with the control group, the depression group had higher HR across wake, REM, and all levels of NREM depth (F(1,51) = 6.3, p = .015). Significant group by sleep stage interactions were found for HRV parameters: SD of normal-to-normal intervals (SDNN; F(2.1,107.7) = 4.4, p = .014) and root mean square differences of successive R-R intervals (RMSSD; F(2.2,113.5) = 3.2, p = .041). No significant group difference was found for SDNN or RMSSD during wake (all, p ≥ .32). However, compared with the control group, the depression group had significantly lower SDNN in REM (p = .040) and all NREM stages (all p ≤ .045), and lower RMSSD during NREM 2 (p = .033) and NREM 3 (p = .034).

CONCLUSIONS

This study suggests that the abnormalities in autonomic cardiac regulation associated with depression and sleep problems are more prominent during sleep, especially NREM sleep, than during wake. This may be due to abnormalities in parasympathetic modulation of cardiac activity.

Relationship of depressive symptoms with arterial stiffness and carotid atherosclerotic burden in the Corinthia study

BACKGROUND

It has been long hypothesized that emotional factors and depression may play role in the development of cardiovascular diseases.

AIM

The aim of this study was to examine the association between depression, arterial stiffness and atheromatic burden in carotid arteries.

DESIGN AND METHODS

Corinthia study is a cross-sectional epidemiological study conducted in subjects aged 40-99 years, inhabitants of the homonym region of Greece. Intima media thickness (IMT) was measured in the left and right common carotid artery, carotid bulb and internal carotid artery. The average of the measurements (mean IMT) and the maximum IMT were determined as the representative value of carotid atherosclerosis burden. Pulse wave velocity was used to evaluate arterial stiffness. The Zung Self-Rating Depression Scale was used to evaluate depressive symptoms in subjects <65 years and the Geriatric Depression Scale in those >65 years.

RESULTS

In this analysis, we included data from 1510 participants. In older subjects (i.e. >65 years), maximum IMT was significantly increased in subjects with depression compared to those without (1.57 ± 0.97 mm vs. 1.74 ± 1.05 mm, P = 0.04). Similarly, the prevalence of atheromatic plaques was higher in subjects with depression (46% vs. 34%, P = 0.005). In the younger subgroup (<65years), there was no difference in mean and maximum IMT. Pulse wave velocity was found higher in the presence of depression (8.35 ± 2.36m/s vs. 7.88 ± 1.77m/s, P = 0.007). No differences emerged for the rest of the variables assessed in the individual subgroups.

CONCLUSIONS

There is an age-dependent association between depression, arterial stiffness and carotid atheromatic burden highlighting the interplay between cardiovascular diseases and emotional status.

Bidirectional relations among common psychiatric and neurologic comorbidities and epilepsy: Do they have an impact on the course of the seizure disorder?

The treatment of epilepsy is not limited to the achievement of a seizure‐free state. It must also incorporate the management of common psychiatric and neurologic comorbidities, affecting on average between 30 and 50% of patients with epilepsy, which have a significant impact on their lives at various levels, including quality of life and the prognosis of the seizure disorder. Mood and anxiety disorders are the most frequent psychiatric comorbidities, whereas stroke and migraine are among the more common neurologic comorbidities, migraine among the younger patients and stroke among the older patients. Not only do these psychiatric and neurologic comorbidities each have a bidirectional relation with epilepsy, but primary mood disorders have a bidirectional relation with these 2 neurologic disorders. Furthermore, depression and migraine have been each associated with a more severe epilepsy course, whereas depression has been associated with a more severe course of stroke and migraines. The purpose of this article is to review the clinical implications of the complex relations among epilepsy and these 3 comorbid disorders, and to identify any clinical and/or experimental evidence that may suggest that having more than one of these comorbid disorders may increase the risk of and course of epilepsy.

Role of infarct location and pre-existing depression on cardiac baroreceptor sensitivity in subacute ischemic stroke

Reduced cardiac baroreceptor sensitivity (BRS) after acute stroke is associated with worse outcome. The underlying mechanisms of reduced BRS are unclear. We evaluated cross correlation BRS (xBRS) in 184 patients with suspected acute ischemic stroke within 72 h of symptom onset. Among these patients, 22 had a transient ischemic attack (TIA) and 27 had a stroke mimic. Sixty-four age- and sex-matched ambulant control subjects without stroke were included. Compared with controls, xBRS was significantly lower in patients with ischemic stroke, TIA, and stroke mimics (4.6, 4.7, and 4.4, respectively, vs 6.6, p < 0.01). There was no difference in xBRS between right and left hemispheric infarctions (4.3 vs 4.9, p = 0.144), right and left insular infarctions (4.5 vs 5.3, p = 0.286), and insular infarction vs non-insular infarctions (4.7 vs 4.5, p = 0.996). Stroke patients with pre-existing depression/use of antidepressant medication had lower xBRS values than stroke patients with normal mental health (2.9 vs 4.8, p < 0.05). Control patients with depression also had lower xBRS compared to controls without depression (3.4 vs 5.9, p < 0.01). Our results suggest that decreased xBRS in the subacute phase after stroke is not associated with infarct localization. We found preliminary evidence for an association between pre-existing depression and use of antidepressant medication, and decreased BRS.

Affective impairment in chronic low blood pressure

OBJECTIVE

Physical complaints such as faintness, dizziness, cold limbs and headaches have been well-established in chronic low blood pressure (hypotension). This study investigated the occurrence of adverse emotional states and the symptoms of depression in this condition. As autonomic dysregulation, particularly diminished sympathetic tone, is believed to be involved in the etiology of hypotension, the impact of different facets of autonomic cardiovascular control on mood and depressive symptoms was also explored.

METHODS

Forty individuals with chronic hypotension and forty normotensive control persons were presented with the Mood Scale and Beck Depression Inventory. Stroke volume, cardiac output, pre-ejection period, Heather index and aortic peak blood flow velocity were recorded under resting conditions as indices of beta-adrenergic inotropic drive. Respiratory sinus arrhythmia and baroreflex sensitivity were additionally obtained.

RESULTS

Hypotensive individuals scored markedly higher on both questionnaire scales than controls, indicating an adversely affected emotional state and more severe depressive symptoms. In the entire sample, cardiac output, Heather index, and aortic peak blood flow velocity correlated negatively with the questionnaire scores; according to regression analysis, the Heather index explained the largest proportion of test score variance.

CONCLUSION

Although hypotension does not constitute a serious medical condition, the findings of an adverse affective state and increased burden with depressive symptoms corroborate the view that it can have a considerable impact on wellbeing and quality of life. The correlations of the beta-adrenergic indices with the questionnaire scales indicate that cardiac sympathetic regulation plays a key role in the psychophysiological mediation of hypotension-related mood impairment.

Depression predicts mortality and hospitalization in heart failure: A six-years follow-up study

BACKGROUND

The aim of this study is to evaluate the prevalence of depressive symptoms (DS) and its relation on hospitalization for cardiovascular (CV) causes and all-cause mortality risk among outpatients with HF.

METHODS

A prospective study was conducted on 130 adult outpatients with HF. The Beck Depression Inventory Scale-second edition (BDI-II) was used to screen for DS. All-cause mortality and hospitalization for CV causes were registered over 6 years. Logistic regression and multinomial logistic regression analysis were used to evaluate the independent prognostic value of DS on mortality and hospitalization for CV causes after adjustment for clinical risk factors.

RESULTS

During a mean follow-up of 6 years, 44% of patients were classified as having DS. Sixty-two participants died for all causes, representing 61% of those with DS and 37% of those without (p=0.006); Forty-nine participants (38%) were hospitalized for CV causes, representing 49% of those with DS and 29% of those without (p=0.027). Logistic regression analysis indicated that DS predicted all-cause mortality (OR: 2.905; 95% CI:1.228-6.870; p=0.006) and multinomial logistic regression indicated that DS were predictive of hospitalization for CV causes (OR: 3.169; 95% CI: 1.230-8.164; p=0.027). These associations were independent of conventional risk factors.

LIMITATIONS

Only outpatient sample; measure of DS only at baseline; cause of death was not known.

CONCLUSION

This study, first held in a portuguese population, showed that DS are independent predictors of death and hospitalization for CV causes among HF patients and its impact persists over 6 years.

Serotonin and norepinephrine reuptake inhibitors antidepressant use is related to lower baroreflex sensitivity independently of the severity of depressive symptoms. A community-study of 9213 participants from the Paris Prospective Study III

BACKGROUND AND AIMS

We assess the respective relationship of high depressive symptoms and antidepressant use (ATD) with baroreflex sensitivity (BRS) in subjects from the community who enrolled the Paris Prospective Study III.

METHODS

Recruitment took place in a large health preventive centre in Paris (France), between May 2008 and June 2012. BRS was investigated by spectral analysis of the spontaneous carotid distension rate and RR intervals using non-invasive high-resolution ultrasound carotid-echotracking. A total score ≥7 on a 13-item standardized questionnaire defined the presence of high depressive symptoms. Information on ATD use was obtained on a face-to-face interview with a medical doctor who checked the most recent medical prescriptions and/or medical package.

RESULTS

There were 9213 participants aged 50-75 years (38.6% of women), including 5.6% with high-depressive symptoms and 5.2% on ATD. High depressive symptoms were not associated with low BRS (below the median) even in unadjusted logistic regression analysis (OR = 1.09; 95%CI: 0.91-1.30). Instead, ATD use was related to low BRS in multivariate logistic regression analysis (OR = 1.27; 95% CI: 1.04-1.54). This association remains after adjusting for and matching on propensity score of receiving ATD. A specific association with serotonin and norepinephrine reuptake inhibitors was observed (OR = 1.94; 95% CI: 1.16-3.22).

CONCLUSIONS

ATD use and serotonin and norepinephrine reuptake inhibitors in particular, but not high depressive symptoms, is associated with low BRS. If confirmed, these results may bring novel insights into the mechanisms linking depressive symptoms and/or ATD use with cardiovascular disease onset.

Investigation of heart rate variability in major depression patients using wavelet packet transform

Studies conducted in major depression (MD) patients have reported a high risk of cardiac morbidity as a result of the relationship between changed cardiovascular activity (CA) and autonomic dysfunctions. The investigation of heart rate variability (HRV) gives valuable idea about variances in autonomic CA of MD patients. To get this knowledge, frequency-domain HRV analysis is frequently performed using Fourier transformation (FT) or discrete-wavelet transformation (DWT) to decompose the data into high-frequency (HF) and low-frequency (LF) bands. Nevertheless, it has been reported that the FT is not useful for nonstationary HRV signals and the DWT does not ensure required frequency boundaries of each band. This study aims to compare the frequency-domain HRV features using wavelet-packet-transform (WPT) with absolutely excellent approximation to required band ranges between the controls and patients. In addition to LF and HF band energies, sympathovagal balance that indicates the variation of sympathetic and parasympathetic activities were compared between two groups. Patients had a significantly lower HF energy, higher values of LF energy and higher LF/HF ratio. Our results recommend that impairments in coordination between parasympathetic and sympathetic behavior in MD patients can be assessed by HRV analysis using WPT with high resolution decomposition for needed bands.

Depressive affect and hospitalization risk in incident hemodialysis patients

BACKGROUND AND OBJECTIVES

Recent studies demonstrated an association between depressive affect and higher mortality risk in incident hemodialysis patients. This study sought to determine whether an association also exists with hospitalization risk.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

All 8776 adult incident hemodialysis patients with Medical Outcomes Study Short Form 36 survey results treated in Fresenius Medical Care North America facilities in 2006 were followed for 1 year from the date of survey, and all hospitalization events lasting >24 hours were tracked. A depressive affect score was derived from responses to two Medical Outcomes Study Short Form 36 questions ("down in the dumps" and "downhearted and blue"). A high depressive affect score corresponded with an average response of "some of the time" or more frequent occurrence. Cox and Poisson models were constructed to determine associations of depressive affect scores with risk for time to first hospitalization and risk for hospitalization events, as well as total days spent in the hospital, respectively.

RESULTS

Incident patients with high depressive affect score made up 41% of the cohort and had a median (interquartile range) hospitalization event rate of one (0, 3) and 4 (0, 15) total hospital days; the values for patients with low depressive affect scores were one (0, 2) event and 2 (0, 11) days, respectively. For high-scoring patients, the adjusted hazard ratio for first hospitalization was 1.12 (1.04, 1.20). When multiple hospital events were considered, the adjusted risk ratio was 1.13 (1.02, 1.25) and the corresponding risk ratio for total hospital days was 1.20 (1.07, 1.35). High depressive affect score was generally associated with lower physical and mental component scores, but these covariates were adjusted for in the models.

CONCLUSIONS

Depressive affect in incident hemodialysis patients was associated with higher risk of hospitalization and more hospital days. Future studies are needed to investigate the effect of therapeutic interventions to address depressive affect in this high-risk population.

The link between stress disorders and autonomic dysfunction in muscular dystrophy

Muscular dystrophy is a progressive disease of muscle weakness, muscle atrophy and cardiac dysfunction. Patients afflicted with muscular dystrophy exhibit autonomic dysfunction along with cognitive impairment, severe depression, sadness, and anxiety. Although the psychological aspects of cardiovascular disorders and stress disorders are well known, the physiological mechanism underlying this relationship is not well understood, particularly in muscular dystrophy. Therefore, the goal of this perspective is to highlight the importance of autonomic dysfunction and psychological stress disorders in the pathogenesis of muscular dystrophy. This article will for the first time—(i) outline autonomic mechanisms that are common to both psychological stress and cardiovascular disorders in muscular dystrophy; (ii) propose therapies that would improve behavioral and autonomic functions in muscular dystrophy.

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).

Yoga as a complementary treatment of depression: effects of traits and moods on treatment outcome

Preliminary findings support the potential of yoga as a complementary treatment of depressed patients who are taking anti-depressant medications but who are only in partial remission. The purpose of this article is to present further data on the intervention, focusing on individual differences in psychological, emotional and biological processes affecting treatment outcome. Twenty-seven women and 10 men were enrolled in the study, of whom 17 completed the intervention and pre- and post-intervention assessment data. The intervention consisted of 20 classes led by senior Iyengar yoga teachers, in three courses of 20 yoga classes each. All participants were diagnosed with unipolar major depression in partial remission. Psychological and biological characteristics were assessed pre- and post-intervention, and participants rated their mood states before and after each class. Significant reductions were shown for depression, anger, anxiety, neurotic symptoms and low frequency heart rate variability in the 17 completers. Eleven out of these completers achieved remission levels post-intervention. Participants who remitted differed from the non-remitters at intake on several traits and on physiological measures indicative of a greater capacity for emotional regulation. Moods improved from before to after the yoga classes. Yoga appears to be a promising intervention for depression; it is cost-effective and easy to implement. It produces many beneficial emotional, psychological and biological effects, as supported by observations in this study. The physiological methods are especially useful as they provide objective markers of the processes and effectiveness of treatment. These observations may help guide further clinical application of yoga in depression and other mental health disorders, and future research on the processes and mechanisms.

Exercise and pharmacological treatment of depressive symptoms in patients with coronary heart disease: results from the UPBEAT (Understanding the Prognostic Benefits of Exercise and Antidepressant Therapy) study

OBJECTIVES

The aim of this study was to assess the efficacy of exercise and antidepressant medication in reducing depressive symptoms and improving cardiovascular biomarkers in depressed patients with coronary heart disease.

BACKGROUND

Although there is good evidence that clinical depression is associated with poor prognosis, optimal therapeutic strategies are currently not well defined.

METHODS

One hundred one outpatients with coronary heart disease and elevated depressive symptoms underwent assessment of depression, including a psychiatric interview and the Hamilton Rating Scale for Depression. Participants were randomized to 4 months of aerobic exercise (3 times/week), sertraline (50-200 mg/day), or placebo. Additional assessments of cardiovascular biomarkers included measures of heart rate variability, endothelial function, baroreflex sensitivity, inflammation, and platelet function.

RESULTS

After 16 weeks, all groups showed improvement on Hamilton Rating Scale for Depression scores. Participants in both the aerobic exercise (mean -7.5; 95% confidence interval: -9.8 to -5.0) and sertraline (mean -6.1; 95% confidence interval: -8.4 to -3.9) groups achieved larger reductions in depressive symptoms compared with those receiving placebo (mean -4.5; 95% confidence interval: -7.6 to -1.5; p = 0.034); exercise and sertraline were equally effective at reducing depressive symptoms (p = 0.607). Exercise and medication tended to result in greater improvements in heart rate variability compared with placebo (p = 0.052); exercise tended to result in greater improvements in heart rate variability compared with sertraline (p = 0.093).

CONCLUSIONS

Both exercise and sertraline resulted in greater reductions in depressive symptoms compared to placebo in patients with coronary heart disease. Evidence that active treatments may also improve cardiovascular biomarkers suggests that they may have a beneficial effect on clinical outcomes as well as on quality of life. (Exercise to Treat Depression in Individuals With Coronary Heart Disease; NCT00302068).

Spiritual well-being may buffer psychological distress in patients with implantable cardioverter defibrillators (ICD)

Psychological distress is common in patients with implantable cardioverter defibrillators (ICDs) and has been associated with a worse prognosis. The authors examined whether spiritual wellbeing is associated with reduced psychological distress in patients with ICDs. The Functional Assessment of Chronic Illness Therapy-Spiritual Wellbeing (FACIT-SWB) questionnare and the Hospital Anxiety and Depression Scale (HADS) were used to measure spiritual wellbeing and overall psychological distress. Multivariate linear regression was used to explore the relationship between these variables.The study sample included 46 ICD outpatients (32 M, 14 F; age range 43-83). An inverse association between HADS and FACIT-SWB scores was found, persisting after adjustment for demographics, anxiety/depression, medications, therapist support, and functional status (F = 0.001; β= -0.31, CI: -0.44, -0.19). In conclusion, spiritual wellbeing was independently associated with lower psychological distress in ICD outpatients. Spiritual wellbeing could act as a protective factor against psychological distress in these high-risk patients.

Anxiety, depression and autonomic nervous system dysfunction in hypertension

OBJECTIVES

This study examined the relationship between autonomic nervous system dysfunction, anxiety and depression in untreated hypertension.

PATIENTS AND METHODS

86 newly diagnosed hypertensive patients and 98 healthy volunteers were included in the study. The psychological parameters were assessed with Spielberger State-Trait Anxiety Inventory and Beck Depression Inventory by a skilled psychologist. Autonomic parameters were examined during tilt table examination (10min lying position, 10min passive tilt). Heart rate variability (HRV) was calculated by autoregressive methods. Baroreflex sensitivity (BRS) was calculated by non-invasive sequence method from the recorded beat to beat blood pressure values and RR intervals.

RESULTS

Significantly higher state (42.6±9.3 vs. 39.6±10.7 p=0.05) and trait (40.1±8.9 vs. 35.1±8.6, p<0.0001) anxiety scores were found in the hypertension group. There was no statistically significant difference in the depression level. LF-RRI (Low Frequency-RR interval) of HRV in passive tilt (377.3±430.6 vs. 494.1±547, p=0.049) and mean BRS slope (11.4±5.5 vs. 13.2±6.4, p=0.07) in lying position were lower in hypertensives. Trait anxiety score correlates significantly with sympatho/vagal balance (LF/HF-RRI) in passive tilt position (Spearman R=-0.286, p=0.01).

CONCLUSIONS

Anxiety could play a more important role than depression in the development of hypertension. Altered autonomic control of the heart could be one of the pathophysiological links between hypertension and psychological factors.

Mental stress and ischemic heart disease: evolving awareness of a complex association

The connection between cardiovascular disease and psychosocial risk factors has been the subject of an ever-growing body of literature over the last 50 years. Studies on the role of negative emotions, personality traits, chronic stress and social determinants have brought to light their possible role in triggering acute coronary syndromes, although further studies are required to clarify controversial results regarding the association between cardiovascular risk and important psychological problems such as depression and anxiety. The recognition of the role of emotional events in acute coronary syndromes paved the way for provocation experiments, aimed at inducing mental stress in a controlled setting and then documenting reversible impairment of myocardial perfusion, depolarization anomalies and arrhythmias. This ultimately led to the formalization of the concept of mental stress-induced myocardial ischemia. Accumulating evidence on the mechanistic bases of such phenomena outline a wide range of central and peripheral physiological changes associated with emotions and behaviors, whose effects are exerted on the cardiovascular system, sympathetic nervous system and the hypothalamus-hypophysis neuroendocrine axis. This article outlines the main steps in the identification of psychological aspects as cardiovascular risk factors and emphasizes the relevance of emotional stress as a trigger of acute cardiovascular events. Finally, a description is provided of the pathophysiological mechanisms behind mental stress-induced myocardial ischemia and pathways connecting the heart and brain.

Depressive symptoms and attenuated physiological reactivity to laboratory stressors

There is evidence that depressive symptoms are associated with attenuated physiological reactivity to active stressors. However, it is not known whether blunted reactivity in depressed individuals is stressor-specific. We examined cardiovascular and electrodermal reactivity in non-clinical participants with varying levels of depressive symptoms to different active and passive stressors. Depressive symptoms were inversely related to both blood pressure and skin conductance reactivity during a public speaking task and the viewing of the speech video. However, no effects were found during a cold pressor task. Together these findings suggest that depressive symptoms are related to attenuated sympathetic nervous system reactivity in response to self-relevant stressors.

Effects of depression and anxiety symptoms on cardiac mortality following myocardial infarction: a 2-year follow-up

OBJECTIVE

The purpose of this study was to determine the impact of symptoms of depression and anxiety on mortality in patients hospitalized for acute myocardial infarction (MI).

METHODS

A total of 806 consecutive patients were screened within 15 days after MI and 24-month survival rate was ascertained. The Beck Depression Inventory and the State-Trait Anxiety Inventory were completed by patients hospitalized for MI. We tested the BDI × STAI interaction effect in addition to the BDI and STAI main effects.

RESULTS

At 24 months' follow up cardiac mortality was assessed in 540 of 806 eligible patients (67% response rate); 531 of 806 for whom baseline data were collected (65.9%) were depressed and 556 (69.0%) were anxious after their MI. Fifty-five (10.2%) patients died during the 24-month follow-up. Neither state of anxiety nor depression scores at entry was different between patients who died from those who survived.

CONCLUSIONS

Symptoms of depression and anxiety did not predict cardiac mortality after MI, but despite the negative results regarding the impact of depression on cardiac outcome, it should be stressed that this does not mean that physicians and cardiologists could ignore depression and anxiety.

Gender-dependent impact of major depression on autonomic cardiovascular modulation

Depression has been shown to increase the risk for cardiovascular disease (CVD) more strongly in women than in men. Although the underlying mechanisms are unknown, a putative role of increased sympathetic modulation has been suggested for the association of CVD and depression. The aim of this study was to investigate possible gender-associated differences of autonomic function in healthy volunteers and patients suffering from major depressive disorder (MDD). Linear as well as non-linear measures of heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were obtained in each 18 male and 18 female unmedicated patients and respective control subjects. Gender differences were detectable in healthy subjects showing predominant sympathetic modulation in males. This was most obvious in BPV analysis. These gender differences were abolished in patients suffering from MDD, mainly due to altered autonomic modulation in female patients. Our results indicate that BPV is more sensitive to reveal depression-associated changes of autonomic function as compared to HRV. Moreover, female patients contribute most to the overall difference between patients and controls. The shift in the balance of autonomic function in women might account for the increased prevalence of CVD in these patients.

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.

Pathophysiological basis of cardiovascular disease and depression: a chicken-and-egg dilemma

OBJECTIVE

To describe the pathophysiological basis linking cardiovascular disease (CVD) and depression; to discuss the causal relationship between them, and to review the effects of antidepressant treatment on cardiovascular disease.

METHOD

A review of the literature based on the PubMed database.

DISCUSSION

Depression and cardiovascular disease are both highly prevalent. Several studies have shown that the two are closely related. They share common pathophysiological etiologies or co-morbidities, such as alterations in the hypothalamic-pituitary axis, cardiac rhythm disturbances, and hemorheologic, inflammatory and serotoninergic changes. Furthermore, antidepressant treatment is associated with worse cardiac outcomes (in case of tricyclics), which are not observed with selective serotonin reuptake inhibitors.

CONCLUSION

Although there is a strong association between depression and cardiovascular disease, it is still unclear whether depression is actually a causal factor for CVD, or is a mere consequence, or whether both conditions share a common pathophysiological etiology. Nevertheless, both conditions must be treated concomitantly. Drugs other than tricyclics must be used, when needed, to treat the underlying depression and not as mere prophylactic of cardiac outcomes.

The role of the selective serotonin re-uptake inhibitor sertraline in nondepressive patients with chronic ischemic heart failure: a preliminary study

BACKGROUND

Selective serotonin re-uptake inhibitors (SSRIs) have been associated with better psychiatric status, functional capacity, and fewer arrhythmias in depressive patients with heart failure (HF). In this study, we tested the impact of sertraline (an SSRI) on patients with HF, but not clinical depression.

METHODS

We studied 62 clinically stable, nondepressive patients with ischemic HF (New York Heart Association class: I-II), and implantable cardioverter-defibrillator (ICD). Following psychiatric evaluation and quality of life (QoL) assessment, 24-hour electrocardiogram recordings including heart rate variability (HRV) and ICD interrogation were performed every 4 months for 1 year. Ventricular effective refractory period (ERP) at 600-, 500-, and 400-ms cycle length and the inducibility of ventricular tachycardia (VT) were assessed via the ICD. After that, sertraline 50 mg/day was administered for 12 months and the whole evaluation was repeated.

RESULTS

Sertraline was associated with fewer ventricular extrasystoles per 24 hours and a significant change in HRV (increase in mean R-R, 5-minute standard deviation of RR intervals, and root mean-square difference of successive RR intervals, and reduction in ultra and very low frequency). It was also followed by an improvement in patients' QoL. A trend toward a decrease was observed in the number of recalled nonsustained VTs. The episodes of sustained VT were not significantly reduced. Ventricular ERPs and VT inducibility remained unaltered.

CONCLUSION

In clinically stable, nondepressive patients with ischemic HF and ICD, sertraline is associated with reduced ventricular extrasystoles, better QoL, and a possible improvement in some HRV indexes. This suggests that SSRIs may have a favorable clinical impact on these patients, independent of the improvement in depressive symptoms.

Depression and CHD risk: how should we intervene?

Depression is common in the community and is a risk factor for the development of coronary heart disease (CHD). In patients with CHD, the prevalence of major depression is nearly 20% and the prevalence of minor depressive disorder is approximately 27%. When present in patients with existing CHD, depression is independently associated with worse outcome, including higher morbidity and mortality, and worse health status. Observational studies suggest that use of antidepressant medications in patients with CHD is associated with decreased risk of cardiovascular events. However, only one randomized controlled trial, the ENRICHD (Enhancing Recovery in Coronary Heart Disease) study, was designed to evaluate whether treatment of depression in patients with CHD can improve cardiac prognosis. Although the study showed that cognitive behavior therapy was better than usual care in improving depression, there was no improvement in all-cause mortality or recurrent cardiac events. There have been no clinical trials specifically designed to evaluate whether pharmacologic treatment of depression improves cardiovascular outcomes in patients with CHD. Thus, there is a clear need for additional trials testing interventions to improve cardiac prognosis based on treatment of depression. In the meantime, depression remains an important illness in its own right and deserves treatment. Safe and effective treatments of depression in patients with CHD include cognitive behavior therapy and selective serotonin reuptake inhibitors.

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.

Cardiovascular abnormalities in patients with major depressive disorder: autonomic mechanisms and implications for treatment

This article provides a detailed review of the association of major depression with coronary heart disease (CHD), examines the biological variables underpinning the linkage and discusses the clinical implications for treatment. When considering the co-morbidity between major depressive disorder (MDD) and CHD it is important to differentiate between (i) the prevalence and impact of MDD in those with existing CHD and (ii) MDD as a risk factor for the development of CHD. Whether the same biological mechanisms are at play in these two instances remains unknown. Depression is common in patients with CHD. Importantly, depression in these patients increases mortality. There is also consistent evidence that MDD is a risk factor for the development of CHD. The relative risk of developing CHD is proportional to the severity of depression and is independent of smoking, obesity, hypercholesterolaemia, diabetes mellitus and hypertension. There is a clear need to identify the underlying neurochemical mechanisms responsible for MDD and their linkage to the heart and vascular system. Of particular interest are activation of stress pathways, including both the sympathetic nervous system and hypothalamic-pituitary-adrenal axis, and inflammatory-mediated atherogenesis. Elevated sympathetic activity, reduced heart rate variability and increased plasma cortisol levels have been documented in patients with MDD. In addition to direct effects on the heart and vasculature, activation of stress pathways may also be associated with increased release of inflammatory cytokines such as interleukin-6 and tumour necrosis factor-alpha. Elevated levels of C-reactive protein are commonly observed in patients with MDD. The majority of investigations examining treatment of depression following myocardial infarction have focused on safety and efficacy; there is little evidence to indicate that treating depression in these patients improves survival. Given that strategies for preventive therapy remain incompletely formulated, future research should focus on generating a better understanding of the neurobiology of MDD and heart disease as a basis for rational and effective therapy.

Depression after coronary artery disease is associated with heart failure

OBJECTIVES

The purpose of this study was to evaluate the influence of post-coronary artery disease (CAD) depression diagnosis on heart failure (HF) incidence.

BACKGROUND

Depression has been shown to be a risk factor for poor outcomes among CAD patients. However, little is known about the influence of depression on HF development in CAD patients.

METHODS

Patients (n = 13,708) without a diagnosis of HF and depression (International Classification of Diseases-Ninth Revision [ICD-9] codes: 296.2 to 296.36 and 311) and who were not prescribed antidepressant medication (ADM) at the time of CAD diagnosis (>or=70% stenosis) were studied. For those with available medication records (n = 7,719), patients subsequently diagnosed with depression were stratified by use of ADM. Patients were followed until HF diagnosis (physician-diagnosed or ICD-9 code: 428) or death. Results were analyzed by Cox proportional hazards regression models.

RESULTS

A total of 1,377 patients (10.0%) had a post-CAD clinical depression diagnosis. The incidence of HF among those without a post-CAD depression diagnosis was 3.6 per 100 compared with 16.4 per 100 for those with a post-CAD depression diagnosis. Depression was associated with an increased risk for HF incidence (adjusted hazard ratio [HR]: 1.50, p < 0.0001). Results were similar among those with available follow-up medication information (vs. no depression: depression without ADM use [HR: 1.68, p < 0.0001]; depression with ADM use [HR: 2.00, p < 0.0001]). No difference was found between depressed patients with and without ADM treatment (HR: 0.84, p = 0.24).

CONCLUSIONS

Depression diagnosis was shown to be associated with an increased incidence of HF after CAD diagnosis, regardless of ADM treatment. This finding suggests the need to further study the effect of depression on HF risk among CAD patients.

The association of depression with platelet activation: evidence for a treatment effect

BACKGROUND

Depression is associated with an increased risk of cardiovascular disease (CVD). Although the mechanism is uncertain, prothrombotic and inflammatory factors may play a role.

OBJECTIVES

As platelets play a key role in CVD, we determined first, whether depressed individuals had more activated platelets than non-depressed individuals and second, whether treatment of depression reduced platelet activation levels.

PATIENTS/METHODS

We recruited 108 depressed outpatients and 45 control subjects all without a history of CVD. After psychological assessment, the depressed patients were offered treatment with medication and/or psychotherapy. Flow cytometric markers of platelet activation and level of depression were assessed at baseline and at 4 weeks and 6 months after treatment.

RESULTS

Depression was associated with increased platelet activation with a higher number of circulating CD62p (0.76x10(9) L(-1) vs. 0.46, P=0.019) and CD63 (P=0.05) positive platelets compared with controls. Patients with depression also had more circulating platelet-leukocyte aggregates than controls (P<0.001). There was a positive correlation between the severity of depression and the level of platelet activation. Platelets from depressed patients were also hyperreactive to adenosine 5 -diphosphate (ADP) stimulation with increased CD62p and CD63 exposure (P=0.003 and 0.019, respectively). Six months of treatment resulted in a reduced number of circulating CD62p and CD63 positive platelets (29.84% and 53.38% decrease) and a 20.9% reduction in CD63 exposure after ADP activation.

CONCLUSIONS

Depression is associated with increased in vivo platelet activation and resolution of depression using psychotherapy and/or medication reduces platelet activation. These findings provide insights into the link between depression and cardiovascular risk.

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.

Depressed mood, positive affect, and heart rate variability in patients with suspected coronary artery disease

OBJECTIVE

To test associations between heart rate variability (HRV), depressed mood, and positive affect in patients with suspected coronary artery disease (CAD). Depression is associated with impaired HRV post acute cardiac events, but evidence in patients with stable coronary artery disease (CAD) is inconsistent.

METHODS

Seventy-six patients (52 men, 24 women; mean age = 61.1 years) being investigated for suspected CAD on the basis of symptomatology and positive noninvasive tests, completed 24-hour electrocardiograms. The Beck Depression Inventory (BDI) was administered, and positive and depressed affect was measured over the study period with the Day Reconstruction Method (DRM). A total of 46 (60.5%) patients were later found to have definite CAD. HRV was analyzed, using spectral analysis.

RESULTS

Typical diurnal profiles of HRV were observed, with greater normalized high frequency (HF) and lower normalized low frequency (LF) power in the night compared with the day. BDI depression scores were not consistently associated with HRV. But positive affect was associated with greater normalized HF power (p = .039) and reduced normalized LF power (p = .007) independently of age, gender, medication with beta blockers, CAD status, body mass index, smoking, and habitual physical activity level. In patients with definite CAD, depressed affect assessed using the DRM was associated with reduced normalized HF power and heightened normalized LF power (p = .007) independently of covariates.

CONCLUSIONS

Relationships between depression and HRV in patients with CAD may depend on affective experience over the monitoring period. Enhanced parasympathetic cardiac control may be a process through which positive affect protects against cardiovascular disease.

Timing is everything: the onset of depression and acute coronary syndrome outcome

BACKGROUND

Conflicting findings have emerged from studies examining the impact of depression on death and readmission following a coronary event, possibly reflecting differences in the measurement of "depression" and the onset of depression in relation to the coronary event. The aim of this study was to examine the relationship between the timing of the depressive episode and 1-year cardiovascular outcome in recruited patients with acute coronary syndrome (ACS).

METHODS

Patients hospitalized with ACS (N = 489) were recruited and assessed for lifetime and current depression by the Composite International Diagnostic Interview (CIDI) depression schedule. Patients were reinterviewed at 1 and 12 months by telephone to assess depression status and cardiovascular outcomes (ACS readmission and cardiac mortality). Mortality registers were also checked.

RESULTS

Cardiovascular outcome was not associated with the presence of lifetime depression before the ACS admission or with existing depression at the time of the ACS admission. In contrast, depression that developed in the month after the ACS event showed a strong relationship with subsequent cardiovascular outcome, even after controlling for traditional cardiac risk factors. Outcome over the 12 months was more strongly predicted by the timing of depression onset than whether the depression was a first-ever (incident) or recurrent episode.

CONCLUSIONS

Only a depressive episode that commenced following an ACS admission was associated with a poorer cardiovascular outcome. If confirmed, this finding would narrow the list of causal mechanisms previously proposed to account for the relationship between depression and coronary events.

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.

Hindlimb unloading elicits anhedonia and sympathovagal imbalance

The hindlimb-unloaded (HU) rat model elicits cardiovascular deconditioning and simulates the physiological adaptations to microgravity or prolonged bed rest in humans. Although psychological deficits have been documented following bed rest and spaceflight in humans, few studies have explored the psychological effects of cardiovascular deconditioning in animal models. Given the bidirectional link established between cardiac autonomic imbalance and psychological depression in both humans and in animal models, we hypothesized that hindlimb unloading would elicit an alteration in sympathovagal tone and behavioral indexes of psychological depression. Male, Sprague-Dawley rats confined to 14 days of HU displayed anhedonia (a core feature of human depression) compared with casted control (CC) animals evidenced by reduced sucrose preference (CC: 81 +/- 2.9% baseline vs. HU: 58 +/- 4.5% baseline) and reduced (rightward shift) operant responding for rewarding electrical brain stimulation (CC: 4.4 +/- 0.3 muA vs. 7.3 +/- 1.0 muA). Cardiac autonomic blockade revealed elevated sympathetic [CC: -54 +/- 14.1 change in (Delta) beats/min vs. HU: -118 +/- 7.6 Delta beats/min] and reduced parasympathetic (CC: 45 +/- 11.8 Delta beats/min vs. HU: 8 +/- 7.3 Delta beats/min) cardiac tone in HU rats. Heart rate variability was reduced (CC: 10 +/- 1.4 ms vs. HU: 7 +/- 0.7 ms), and spectral analysis of blood pressure indicated loss of total, low-, and high-frequency power, consistent with attenuated baroreflex function. These data indicate that cardiovascular deconditioning results in sympathovagal imbalance and behavioral signs consistent with psychological depression. These findings further elucidate the pathophysiological link between cardiovascular diseases and affective 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.

Pathological baroreceptor sensitivity in patients suffering from somatization disorders: do they correlate with symptoms?

AIM

We conducted a study to investigate whether patients with somatization disorders (ICD-10, F45.0) show abnormal values in autonomic testing.

METHOD

35 patients with a diagnosis of somatization disorder (SP) were matched to 35 healthy volunteers (HV). International standardized autonomic testing based on heart rate variation and continuously measured blood pressure signals was used to assess autonomic activity and establish baroreceptor sensitivity (BRS). Three different statistical procedures were used to confirm the reliability of the findings.

RESULTS

There were no statistical differences between the 2 groups in age, BMI, systolic and diastolic blood pressures, and spectral values (total power, low, and high frequency power). However, heart rate was higher (p=0.044) and baroreceptor sensitivity was lower (p=0.002) in the patients compared to the healthy volunteers. Median BRS (+/-S.E.M.) of patients was 9.09+/-0.65 compared to 12.04+/-0.94 ms/mmHg in healthy volunteers. Twenty-two of the 35 patients had a BRS of -1.0S.D. below the mean of HV. SP with lower values differed from SP with normal BRS in values of total power, low-, mid-, and high-frequency bands (p<0.01 to <0.0001). No differences in psychometric testing were found between patients with lower or higher BRS. In addition, no correlation whatsoever was found in relation to autonomic variables between HV and SP, except for a higher LF/HF quotient in the latter (p<0.05).

CONCLUSION

Autonomic regulation was impaired in 62% of patients with a somatization disorder. Severity of clinical symptoms measured by psychometric instruments did not preclude autonomic function impairment. Accordingly, autonomic dysfunction may constitute an independent somatic factor in this patient group.

Evaluation of baroreceptor reflex function in the chronic mild stress rodent model of depression

OBJECTIVE

There is a bidirectional relationship between mood disorders (e.g., depression) and altered cardiovascular regulation (e.g., heart disease); however, the precise causal and/or common mechanisms underlying this association are unclear. In previous studies, we have noted indications of altered sympathetic drive to the heart in rats that exhibit anhedonia, an operational sign of depression induced by subjecting the animals to a series of mild and unpredictable stressors (chronic mild stress (CMS) rodent model of depression). The purpose of the present study was to more fully characterize baroreceptor reflex function in rats with experimentally induced depression.

METHODS

Male, Sprague-Dawley rats were exposed to either 4 weeks of mild, unpredictable stressors (CMS group) or standard housing conditions (control group). Depression-like behavior, resting hemodynamic and cardiac parameters, and baroreceptor reflex function were investigated in all animals after the CMS period.

RESULTS

CMS produced anhedonia, evidenced by reduced sucrose intake and sucrose preference, as well as elevated resting heart rate (HR), slightly elevated blood pressure, and reduced HR variability. These animals also exhibited significantly attenuated sympathoexcitatory responses to hypotension, and an elevation of basal sympathetic nerve activity.

CONCLUSIONS

These findings suggest that CMS is associated with altered sympathoexcitatory responses after baroreceptor unloading and provide further insights into potential common mechanisms underlying the association of depression and altered cardiovascular control.

Understanding prognostic benefits of exercise and antidepressant therapy for persons with depression and heart disease: the UPBEAT study--rationale, design, and methodological issues

BACKGROUND

Depression is relatively common in patients with coronary heart disease (CHD) and is associated with worse prognosis. Recently there has been interest in evaluating the impact of treating depression on clinical outcomes. Anti-depressant medications have been shown to be safe and efficacious for many patients; exercise also may be effective for treating depression and may also improve cardiopulmonary functioning. However, methodological limitations of previous studies have raised questions about the value of exercise, and no study has compared the effects of exercise with standard anti-depressant medication in depressed cardiac patients.

PURPOSE

UPBEAT is a randomized clinical trial (RCT) funded by NHLBI to evaluate the effects of sertraline or exercise compared to placebo on depression and biomarkers of cardiovascular risk in patients with CHD and elevated depressive symptoms.

METHODS

The UPBEAT study includes 200 stable CHD patients with scores on the Beck Depression Inventory (BDI) > or =9 randomized to 4 months of treatment with aerobic exercise, sertraline, or placebo. The primary outcomes include depressive symptoms determined by clinical ratings on the Hamilton Rating Scale for Depression (HAM-D) and measures of heart rate variability (HRV), baroreflex control (BRC), vascular function (i.e., flow-mediated dilation (FMD)), and measures of inflammation and platelet aggregation.

RESULTS

This article reviews the rationale and design of UPBEAT and addresses several key methodologic issues that were carefully considered in the development of this protocol: the use of a placebo control condition in depressed cardiac patients, study design, and selection of intermediate endpoints or biomarkers of cardiovascular risk.

LIMITATIONS

This study is not powered to assess treatment group differences in CHD morbidity and mortality. Intermediate endpoints are not equivalent to 'hard' clinical events and further studies are needed to determine the clinical significance of these biomarkers.

CONCLUSIONS

The UPBEAT study is designed to assess the efficacy of exercise in treating depression in cardiac patients and evaluates the impact of treating depression on important biomarkers of cardiovascular risk.

Social isolation in prairie voles induces behaviors relevant to negative affect: toward the development of a rodent model focused on co-occurring depression and anxiety

Recent evidence suggests substantial overlap between mood and anxiety disorders, both in clinical presentation and associated features. A theoretical framework to account for this overlap focuses on negative affectivity, defined as the disposition to experience negative emotional states, including fear, sadness, and guilt. This model has been successful in explaining the co-occurrence of depressive and anxiety disorders in humans. As a next step, development of an animal model focused on both depression- and anxiety-relevant behaviors may advance understanding of depression-anxiety symptom overlap, relations of these disorders with associated medical conditions and responses to treatment. This study was designed to investigate inducible and quantifiable depression- and anxiety-like behaviors in prairie voles (Microtus ochrogaster). Adult, female prairie voles were exposed to 4 weeks of social pairing (control) or isolation, an established stressor for socially monogamous mammals (including humans). Operational measures of depression (sucrose intake and behaviors in the forced swim test), anxiety (behaviors in the elevated plus maze), and aggression (responses to an unrelated prairie vole pup) were investigated. Social isolation induced a progressive decline in sucrose intake and increased immobility time during the forced swim test. Social isolation also decreased the amount of time spent in the open arms of the elevated plus maze, and increased pup-directed attack behavior. The current findings suggest that isolation induces behaviors reflecting elevated negative affect. These results may provide a foundation for creating a rodent model to examine the mechanisms underlying comorbid mood and anxiety disorders.