Mind and heart: heart rate variability in major depressive disorder and coronary heart disease - a review and recommendations

Reference values for time- and frequency-domain heart rate variability measures

BACKGROUND

The analysis of heart rate variability (HRV) has become an established procedure in recent decades. Because there are no appropriate reference values available, HRV findings can still only be compared within a group or in individuals in longitudinal studies.

OBJECTIVE

The objectives of the present study were to examine a group of healthy subjects of different ages and sexes and to identify reference values for common HRV parameters.

METHODS

Long-term 24-hour electrocardiograms of 695 voluntary subjects were recorded by using a 2-channel Holter system over a period of 24 hours during daily activities.

RESULTS

Reference values for men and women in 10-year age groups were calculated for standard deviation of NN intervals, root mean square of successive differences of NN intervals, standard deviation of the average of all consecutive 5-minute NN intervals, percentage of consecutive NN intervals that deviate from one another by more than 50 ms, low-frequency power normalized unit, high-frequency power normalized unit, low frequency/high frequency ratio, SD1, and SD2. The 5th and 95th percentiles were given for each sex and for the age groups 20-30, 30-40, 40-50, and 50-60 years. We observed a consistent decrease in HRV measures with increasing age as well as a sex dependency of HRV findings.

CONCLUSION

We studied a large group of healthy subjects and identified reference values for commonly used HRV measures for 24-hour ECG measurements. The reference values differed considerably from the values published in 1996 in the Guidelines of the Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. In the future, steps should be taken to expand the database and define reference values for the age groups under 20 and over 60 years. It would be desirable to obtain reference values for short-term recordings (eg, 5-minute recordings) as well.

Diminished autonomic neurocardiac function in patients with generalized anxiety disorder

BACKGROUND

Generalized anxiety disorder (GAD) is a chronic and highly prevalent disorder that is characterized by a number of autonomic nervous system symptoms. The purpose of this study was to investigate the linear and nonlinear complexity measures of heart rate variability (HRV), measuring autonomic regulation, and to evaluate the relationship between HRV parameters and the severity of anxiety, in medication-free patients with GAD.

METHODS

Assessments of linear and nonlinear complexity measures of HRV were performed in 42 medication-free patients with GAD and 50 healthy control subjects. In addition, the severity of anxiety symptoms was assessed using the State-Trait Anxiety Inventory and Beck Anxiety Inventory. The values of the HRV measures of the groups were compared, and the correlations between the HRV measures and the severity of anxiety symptoms were assessed.

RESULTS

The GAD group showed significantly lower standard deviation of RR intervals and the square root of the mean squared differences of successive normal sinus intervals values compared to the control group (P<0.01). The approximate entropy value, which is a nonlinear complexity indicator, was also significantly lower in the patient group than in the control group (P<0.01). In correlation analysis, there were no significant correlations between HRV parameters and the severity of anxiety symptoms.

CONCLUSION

The present study indicates that GAD is significantly associated with reduced HRV, suggesting that autonomic neurocardiac integrity is substantially impaired in patients with GAD. Future prospective studies are required to investigate the effects of pharmacological or non-pharmacological treatment on neuroautonomic modulation in patients with GAD.

Anticipation and frequency of feeding affect heart reactions in domestic pigs

Measuring heart reactions has become a widely used method for the assessment of emotions. Heart rate and its variability, which can quite easily be noninvasively recorded, reflect the inputs of the sympathetic and parasympathetic branches of the autonomous nervous system. We tested the hypothesis that frequent anticipation of a positive event results in an increased state of welfare in pigs, expressed as positive arousal in anticipation of announced feeding as well as lowered heart rate and augmented heart rate variability during resting periods. We used a controlled paradigm with 3 groups of young domestic pigs (Sus scrofa domestica). We compared frequent acoustic announcement of feed delivery (group 1: 3 feedings between 0730 h and 1030 h plus 3 feedings between 1200 h and 1530 h) with the same number of feedings as in group 1 but without a temporal relation to the sound (group 2) and with a fixed-schedule feeding (group 3: 2 feedings at 0600 h and 1500 h). Specific cardiac and behavioral reactions indicated short-term (1 min) anticipation in the conditioned group. In this group, heart rate increased (P < 0.001) mainly through vagal withdraw and behavior became more active (P < 0.001). Only the conditioned group displayed changing heart rate characteristics during the sound. Pigs in the frequent unpredictable feed group reacted to feed delivery with increased heart rates (P < 0.001), whereas the heart-rate characteristics of pigs with the fixed schedule were unchanged during the sound and while the other 2 treatment groups were feeding. Clear evidence for long-term anticipation (over the course of hours) was not present in the data. Comparisons between the 3 treatment groups suggested that in housing conditions where pigs cannot obtain feed by their actions but must wait for feed delivery, feeding at 2 fixed times would be preferred. Animals in this treatment group presented lower resting heart rates at the end of the experiment than animals in the other 2 groups (P < 0.01). Therefore, merely announcing a positive stimulus without giving control to its access is apparently not suitable for increasing welfare.

Acute coronary syndrome and depression: A review of shared pathophysiological pathways

OBJECTIVE

To examine the evidence for shared pathophysiological pathways in acute coronary syndrome and major depression and to conceptualise the dynamic interplay of biological systems and signalling pathways that link acute coronary syndrome and depression within a framework of neuro-visceral integration.

METHODS

Relevant articles were sourced via a search of published literature from MEDLINE, EMBASE and PubMed using a variety of search terms relating to biological connections between acute coronary syndrome and depression. Additional articles from bibliographies of retrieved papers were assessed and included where relevant.

RESULTS

Despite considerable research efforts, a clear understanding of the biological processes connecting acute coronary syndrome and depression has not been achieved. Shared abnormalities are evident across the immune, platelet/endothelial and autonomic/stress-response systems. From the available evidence, it seems unlikely that a single explanatory model could account for the complex interactions of biological pathways driving the pathophysiology of these disorders and their comorbidity.

CONCLUSION

A broader conceptual framework of mind-body or neuro-visceral integration that can incorporate the existence of several causative scenarios may be more useful in directing future research and treatment approaches for acute coronary syndrome-associated depression.

Characterising acute coronary syndrome-associated depression: Let the data speak

Depression in the context of acute coronary syndrome (ACS) is understood to confer increased morbidity and mortality risk. The pathophysiological mechanisms underlying this association remain poorly understood, although several candidates including inflammation, cardiac autonomic dysregulation, and behavioural factors are viewed as of key importance. No single bio-behavioural explanatory model of ACS-associated depression has emerged, likely due the substantial heterogeneity across both conditions. We studied 344 patients with ACS; 45 fulfilled diagnostic (DSM-IV) criteria for a major depressive episode occurring within 1-month of ACS, and 13 had ongoing major depression that pre-dated ACS and continued through to 1 month post-ACS. We employed two statistical methods (multinomial logistic regression; and latent class analysis) and a range of immunological, autonomic and nutritional markers in an attempt to characterise a biological basis for ACS-associated depression. Regression modelling failed to accurately predict categorical group membership of ACS-associated depression. An alternative data-driven approach produced a three-class solution, with the derived classes differing on measure of C-reactive protein, vitamin D, omega-6:omega-3 ratio, heart rate variability, and age (all p⩽0.004). The majority of participants with ACS-associated and ongoing depression were members of the class characterised by the greatest biological disturbance. Patients with depression differed from those without depression on a range of psychological trait and state variables; additionally reporting poorer sleep quality, higher levels of social isolation, and functional impairment, but had similar biological profiles. Patients with ongoing depression generally had higher scores on these psychological/behavioural measures. Our novel analytic approach identified a combination of biomarkers suggestive of a role for immune, autonomic, and nutritional pathways in the manifestation of depression during ACS, in the context of additional psychosocial and behavioural vulnerabilities. Further studies are required to confirm the causal role of these factors in perpetuating depression and increasing risk of poor-health outcomes.

The association between mood and anxiety disorders, and coronary heart disease in Brazil: a cross-sectional analysis on the Brazilian longitudinal study of adult health (ELSA-Brasil)

Background: Associations between major depressive disorder (MDD) and coronary heart disease (CHD) have been established, and these associations increase risk of future morbidity and mortality. Prior research has been carried out in high-income countries. Here we examine associations between the mood and anxiety disorders, and CHD in a large cohort at baseline from Brazil, a country facing a variety of challenges that may affect these associations.

Methods: Participants included 15,105 civil servants aged 35 to 74 at baseline (2008–2010) from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). CHD (N = 721) included self-reported angina pectoris (n = 305), myocardial infarction (n = 259) and coronary revascularization (n = 239). Hierarchical logistic regression analyses were conducted to estimate odds ratios and confidence intervals.

Results: Major findings indicate that comorbid MDD and anxiety disorders (n = 434) are associated with a threefold increase in CHD, MDD alone (n = 170) with a twofold increase in CHD, while generalized anxiety disorder alone (n = 1,394) and mixed anxiety and depression disorder (n = 1,844) – symptoms present, but diagnostic threshold not reached – are associated with a 1.5-fold increase in CHD, after full adjustment for covariates.

Conclusion: The association with CHD is greatest in those with psychiatric comorbidity, while associations were also observed in MDD and generalized anxiety disorder without comorbidity. While findings are limited by the cross-sectional design of the study, given the known risks associated with comorbidity of the mood and anxiety disorders with CHD, findings reinforce the importance of comprehensive health assessment in Brazil.

The Association between Antidepressant Medications and Coronary Heart Disease in Brazil: A Cross-Sectional Analysis on the Brazilian Longitudinal Study of Adult Health (ELSA-Brazil)

Background: Recent studies have highlighted associations between use of antidepressant medications and coronary heart disease (CHD). Tricyclic antidepressants (TCA) are not recommended in patients with CHD as they may increase morbidity and mortality. However, this class of antidepressants is freely prescribed in public health pharmacies, while access to other classes of antidepressants is restricted in Brazil. Here, we examine the associations between antidepressant use and prevalent CHD in a large cohort from Brazil.

Methods: Participants included 14,994 civil servants aged 35–74 years from the baseline assessment of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). CHD (n = 710) included stable angina, myocardial infarction, and coronary revascularization. Univariate (unadjusted) and multivariate (adjusted) logistic regression analyses were conducted to estimate odds ratios and confidence intervals.

Results: After full adjustment for covariates, TCA use (n = 156) was associated with a twofold increase in prevalent CHD, relative to non-use (n = 14,076). Additional sensitivity analysis revealed a threefold association for myocardial infarction (OR: 2.96, 95% CI: 1.41–6.21) and coronary revascularization (OR: 2.92, 95% CI: 1.28–6.66). There were no significant associations between antidepressant use and stable angina pectoris.

Conclusion: Findings highlight a strong association between TCA use and prevalent CHD. While the cross-sectional design is an important limitation of the present study, findings have important implications for the treatment of cardiac patients in Brazil.

Altered heart rate variability depend on the characteristics of coronary lesions in stable angina pectoris

OBJECTIVE

Dysfunction of cardiac autonomic nerve system is considered as one of risk factors for coronary atherosclerotic heart disease. Heart rate variability (HRV) has been used to study the correlation between damage of coronary artery and dysfunction of autonomic nervous system. We hypothesize the correlation between damage of coronary artery and dysfunction of autonomic nervous system by HRV among subjects with stable angina.

METHODS

A 236 subjects who diagnosed as stable angina pectoris by elective coronary angiography, were divided into two groups by Gensini score system (GS):GS≤32 (GS1) and GS2>32 (GS2). Subgroups were divided based on location of stenosis lesions and the number of coronary artery disease. 86 subjects suspicious with stable angina pectoris with normal coronary angiography were selected as the control group. All subjects were received 24-hour ambulatory electrocardiogram and the result of time-domain HRV was analyzed (SDNN, SDANN, SDNNind, RMSSD, PNN50).

RESULTS

Compared with control group, SDNN, SDNNind and RMSSD lower in GS1, and SDNN, SDANN, SDNNind, RMSSD, PNN50 lower in GS2; ccompared with GS1, SDNN was lower in GS2. Compared with control group, SDNN in one-vessel, SDNN, SDANN in two-vessel diseased and in three-vessel diseased were lower, and compared with two-vessel diseased, SDNN, SDANN lower in three-vessel diseased. Compared with right-coronary artery diseased, SDNN and SDANN in left-coronary artery diseased group were lower, while compared with lesions in left circumflex, SDNN in lesions in left anterior descending artery lower.

CONCLUSION

HRV may be play a crucial role in estimating the correlation between damage of coronary artery and dysfunction of autonomic nerve system.

Efficacy of adjunctive celecoxib treatment for patients with major depressive disorder: a meta-analysis

BACKGROUND

Numerous studies have reported that inflammation is closely associated with depression, and adjunctive non-steroidal anti-inflammatory drug (NSAID) treatment has been suggested as a novel therapeutic approach for depression.

METHODS

We searched electronic databases including Medline, Embase, and the Cochrane Central Register of Controlled Trials. We only included randomized controlled trials comparing adjunctive NSAIDs with placebos for treating depressive episodes.

RESULTS

Of the 654 retrieved entries, we identified four relevant studies with a total of 150 patients (75 NSAID patients and 75 placebo patients) with depressive episodes. All four studies used celecoxib as the NSAID. The patients receiving adjunctive celecoxib had significantly higher mean changes in the Hamilton Rating Scale for Depression scores between baseline and endpoint measurements compared with those receiving placebo (weighted mean difference=3.26, 95% confidence interval; CI=1.81 to 4.71). The adjunctive celecoxib group also showed better remission (odds ratio; OR=6.58, 95% CI=2.55 to 17.00) and response rates (OR=6.49, 95% CI=2.89 to 14.55) than the placebo group. The all-cause drop-out rate was more favorable for the celecoxib group than for the placebo group (OR=0.45, 95% CI=0.18 to 1.13), although the statistical significance was not statistically significant (p=0.09).

CONCLUSION

Adjunctive treatment with NSAIDs, particularly celecoxib, can be a promising strategy for patients with depressive disorder. Future studies with a larger sample size and longer study duration are needed to confirm the efficacy and tolerability of NSAIDs for depression.

Comorbidity clusters in autism spectrum disorders: an electronic health record time-series analysis

OBJECTIVE

The distinct trajectories of patients with autism spectrum disorders (ASDs) have not been extensively studied, particularly regarding clinical manifestations beyond the neurobehavioral criteria from the Diagnostic and Statistical Manual of Mental Disorders. The objective of this study was to investigate the patterns of co-occurrence of medical comorbidities in ASDs.

METHODS

International Classification of Diseases, Ninth Revision codes from patients aged at least 15 years and a diagnosis of ASD were obtained from electronic medical records. These codes were aggregated by using phenotype-wide association studies categories and processed into 1350-dimensional vectors describing the counts of the most common categories in 6-month blocks between the ages of 0 to 15. Hierarchical clustering was used to identify subgroups with distinct courses.

RESULTS

Four subgroups were identified. The first was characterized by seizures (n = 120, subgroup prevalence 77.5%). The second (n = 197) was characterized by multisystem disorders including gastrointestinal disorders (prevalence 24.3%) and auditory disorders and infections (prevalence 87.8%), and the third was characterized by psychiatric disorders (n = 212, prevalence 33.0%). The last group (n = 4316) could not be further resolved. The prevalence of psychiatric disorders was uncorrelated with seizure activity (P = .17), but a significant correlation existed between gastrointestinal disorders and seizures (P < .001). The correlation results were replicated by using a second sample of 496 individuals from a different geographic region.

CONCLUSIONS

Three distinct patterns of medical trajectories were identified by unsupervised clustering of electronic health record diagnoses. These may point to distinct etiologies with different genetic and environmental contributions. Additional clinical and molecular characterizations will be required to further delineate these subgroups.

The contribution of major depression to the global burden of ischemic heart disease: a comparative risk assessment

BACKGROUND

Cardiovascular disease and mental health both hold enormous public health importance, both ranking highly in results of the recent Global Burden of Disease Study 2010 (GBD 2010). For the first time, the GBD 2010 has systematically and quantitatively assessed major depression as an independent risk factor for the development of ischemic heart disease (IHD) using comparative risk assessment methodology.

METHODS

A pooled relative risk (RR) was calculated from studies identified through a systematic review with strict inclusion criteria designed to provide evidence of independent risk factor status. Accepted case definitions of depression include diagnosis by a clinician or by non-clinician raters adhering to Diagnostic and Statistical Manual of Mental Disorders (DSM) or International Classification of Diseases (ICD) classifications. We therefore refer to the exposure in this paper as major depression as opposed to the DSM-IV category of major depressive disorder (MDD). The population attributable fraction (PAF) was calculated using the pooled RR estimate. Attributable burden was calculated by multiplying the PAF by the underlying burden of IHD estimated as part of GBD 2010.

RESULTS

The pooled relative risk of developing IHD in those with major depression was 1.56 (95% CI 1.30 to 1.87). Globally there were almost 4 million estimated IHD disability-adjusted life years (DALYs), which can be attributed to major depression in 2010; 3.5 million years of life lost and 250,000 years of life lived with a disability. These findings highlight a previously underestimated mortality component of the burden of major depression. As a proportion of overall IHD burden, 2.95% (95% CI 1.48 to 4.46%) of IHD DALYs were estimated to be attributable to MDD in 2010. Eastern Europe and North Africa/Middle East demonstrate the highest proportion with Asia Pacific, high income representing the lowest.

CONCLUSIONS

The present work comprises the most robust systematic review of its kind to date. The key finding that major depression may be responsible for approximately 3% of global IHD DALYs warrants assessment for depression in patients at high risk of developing IHD or at risk of a repeat IHD event.