Association between depression and heart rate variability in patients after cardiac surgery: a pilot study

The pathophysiology and management of depression in cardiac surgery patients

Background

Depression is common in the cardiac surgery population. This contemporary narrative review aims to explore the main pathophysiological disturbances underpinning depression specifically within the cardiac surgery population. The common non-pharmacological and pharmacological management strategies used to manage depression within the cardiac surgery patient population are also explored.

Methods

A total of 1291 articles were identified through Ovid Medline and Embase. The findings from 39 studies were included for qualitative analysis in this narrative review.

Results

Depression is associated with several pathophysiological and behavioral factors which increase the likelihood of developing coronary heart disease which may ultimately require surgical intervention. The main pathophysiological factors contributing to depression are well characterized and include autonomic nervous system dysregulation, excessive inflammation and disruption of the hypothalamic-pituitary-adrenal axis. There are also several behavioral factors in depressed patients associated with the development of coronary heart disease including poor diet, insufficient exercise, poor compliance with medications and reduced adherence to cardiac rehabilitation. The common preventative and management modalities used for depression following cardiac surgery include preoperative and peri-operative education, cardiac rehabilitation, cognitive behavioral therapy, religion/prayer/spirituality, biobehavioral feedback, anti-depressant medications, and statins.

Conclusion

This contemporary review explores the pathophysiological mechanisms leading to depression following cardiac surgery and the current management modalities. Further studies on the preventative and management strategies for postoperative depression in the cardiac surgery patient population are warranted.

Association and interaction between clinician-rated measures of depression and anxiety with heart rate variability in elderly patients with psychiatric disorders

Background

Older adults are vulnerable to comorbid depression and anxiety symptoms; however, these conditions are widely underrecognized and often untreated. Understanding their combined manifestation using objective measurements, such as clinician-rated scales and heart rate variability (HRV), can help refine the diagnosis and select a treatment strategy for geriatric patients.

Methods

This study included patients over 65 years who were mainly diagnosed with either category of depressive or anxiety disorders from the psychiatric outpatient clinic in a university hospital. A total of 114 patients met eligibility with a completed collection of electrocardiograms, the Hamilton Depression Rating Scale (HDRS; clinician-rated depression), and the Hamilton Anxiety Scale (HAS; clinician-rated anxiety) to assess the severity of symptoms. Both main and interaction effects between HDRS and HAS on HRV parameters were examined.

Results

Significant interaction effects between clinician-rated depression and anxiety (HDRS × HAS) on HRV reduction in frequency parameters (i.e., nuLF, nuHF, LF/HF ratio) were found, which consistently indicated autonomic nervous system dysregulation. Findings imply that HRV could reflect synergistic effects of comorbid depressive and anxiety symptoms, perhaps due to the amplification of individual symptoms in geriatric patients.

Conclusions

The results imply that using objective measurements can improve diagnostic accuracy, particularly in geriatric patients with comorbid status, and the normalization of the autonomic nervous system might be a candidate target for prevention and treatment.

The Stressful Experience of Goal Orientations Under Frustration: Evidence Using Physiological Means

The purpose of the present study was to test the hypothesis that goal orientation is associated with divergent forms of emotional reactivity under frustration. Goal orientations were assessed using bifurcations of performance goals described earlier. Physiological stress levels were measured via a blood volume pulse analysis after individuals were subjected to a computerized Stroop task using a malfunctioning mouse to induce enhanced frustration. The results indicated that performance-avoidance goals were associated with the highest levels of emotional reactivity, with normative outcome goals being significantly more detrimental than ability goals. We concluded that the motivation to avoid failure or to outperform others is the most detrimental determinant of stress and needs to be avoided by all means. Instead, it is suggested that educators emphasize performance using personal best outcomes or by valuing engagement, deep processing and task completion.

Intensification of functional neural control on heartbeat dynamics in subclinical depression

Subclinical depression (dysphoria) is a common condition that may increase the risk of major depression and leads to impaired quality of life and severe comorbid somatic diseases. Despite its prevalence, specific biological markers are unknown; consequently, the identification of dysphoria currently relies exclusively on subjective clinical scores and structured interviews. Based on recent neurocardiology studies that link brain and cardiovascular disorders, it was hypothesized that multi-system biomarkers of brain-body interplay may effectively characterize dysphoria. Thus, an ad hoc computational technique was developed to quantify the functional bidirectional brain-heart interplay. Accordingly, 32-channel electroencephalographic and heart rate variability series were obtained from 24 young dysphoric adults and 36 healthy controls. All participants were females of a similar age, and results were obtained during a 5-min resting state. The experimental results suggest that a specific feature of dysphoria is linked to an augmented functional central-autonomic control to the heart, which originates from central, frontopolar, and occipital oscillations and acts through cardiovascular sympathovagal activity. These results enable further development of a large set of novel biomarkers for mood disorders based on comprehensive brain-body measurements.

Depressed mood, brooding rumination and affective interference: The moderating role of heart rate variability

Facilitated processing of negative information might contribute to the etiopathogenesis and maintenance of depressive symptoms. Cardiac vagal tone, indexed by heart rate variability (HRV), is believed to represent a proxy of the functional integrity of the neural networks implicated in brooding rumination, affective interference and depression. The present study examined whether HRV may moderate the relation between brooding rumination, affective interference and depressive symptoms in a sample of healthy individuals (n = 68) with different degrees of depressed mood. Self-report measures of depression and brooding were collected, whereas the emotional Stroop task was employed to measure affective interference. Three-minute resting-state electrocardiogram was recorded to obtain time- and frequency-domain vagally mediated HRV parameters. Stepwise linear regression analyses revealed that HRV was a significant moderator of the positive association between depression and brooding rumination, but not of the association between depression and affective interference. An integrated model is supported, in which vagally mediated HRV appeared to potentiate the positive link between depressive symptoms and brooding rumination. Considering that HRV and brooding rumination were found to have an interacting role in determining the severity of depressive symptoms, they may represent potential clinical targets in the prevention and treatment of depressive symptoms.

Análise da variabilidade da frequência cardíaca em crianças submetidas a jogos eletrônicos

Objetivo: avaliar a função autonômica do coração de crianças sadias em situações de jogos eletrônicos, mediante a análise de Variabilidade da Frequência cardíaca.Métodos: participaram deste estudo 60 crianças sadias, que foram monitoradas por um monitor de frequência cardíaca digital e submetidas ao experimento com o jogo eletrônico. A análise da Variabilidade da Frequência cardíaca foi calculadacom emprego da transformada Wavelet Contínua.Resultados: pode-se observar um aumento na intensidade dos valores de baixa frequência/alta frequência, sugerindo influência das fases do protocolo, de modo que houve uma elevação nos valores da fase de Repouso para a fase de Jogo, mas não foi encontrado um valor significativo. Entre as fases de Repouso (1,52±0,97 ms²) e Recuperação (1,89±1,04 ms²) houve um aumento significativo obtendo um valor de p=0,003. Comparando os valores de baixa frequência/alta frequência entre as fases Jogo 2,37±1,20 ms² e Recuperação 1,89±1,04 ms², verificou-se uma redução significativa da relação (p = 0,016).Conclusão: conclui-se que Jogos eletrônicos podem provocar um aumento da atividade simpática, diminuindo a Variabilidade da Frequência cardíaca das crianças estudadas, sugerindo uma situação estressante.

Not All Competitions Come to Harm! Competitive Biofeedback to Increase Respiratory Sinus Arrhythmia in Managers

Despite the positive impact on achievement, competition has been associated with elevated psychophysiological activation, potentially leading to a greater risk of cardiovascular diseases. Competitive biofeedback (BF) can be used to highlight the effects of competition on the same physiological responses that are going to be controlled through BF. However, it is still unknown whether competition could enhance the effects of respiratory sinus arrhythmia (RSA)-BF training in improving cardiac vagal control. The present study explored whether competitive RSA-BF could be more effective than non-competitive RSA-BF in increasing RSA in executive managers, who are at higher cardiovascular risk of being commonly exposed to highly competitive conditions. Thirty managers leading outstanding private or public companies were randomly assigned to either a Competition (n = 14) or a Control (n = 16) RSA-BF training lasting five weekly sessions. Managers in the Competition group underwent the RSA-BF in couples and each participant was requested to produce a better performance (i.e., higher RSA) than the paired challenger. After the training, results showed that managers in the Competition group succeeded in increasing cardiac vagal control, as supported by the specific increase in RSA (p < 0.001), the standard deviation of R-R wave intervals (SDNN; p < 0.001), and root mean square of the successive differences between adjacent heartbeats (rMSSD; p < 0.001). A significant increase in the percentage of successive normal sinus beat to beat intervals more than 50 ms (pNN50; p = 0.023; η2 p = 0.17), low frequency (p = ≤ 0.001; η2 p = 0.44), and high frequency power (p = 0.005; η2 p = 0.25) emerged independently from the competitive condition. Intriguingly, managers who compete showed the same reduction in resting heart rate (HR; p = 0.003, η2 p = 0.28), systolic blood pressure (SBP; p = 0.013, η2 p = 0.20), respiration rate (p < 0.001; η2 p = 0.46), and skin conductance level (SCL; p = 0.001, η2 p = 0.32) as non-competitive participants. Also, the same reduction in social anxiety (p = 0.005; η2 p = 0.25), state (p = 0.038, η2 p = 0.14) and trait anxiety (p = 0.001, η2 p = 0.31), and depressive symptoms (p = 0.023, η2 p = 0.17) emerged in the two groups. The present results showed that managers competing for increasing RSA showed a greater improvement in their parasympathetic modulation than non-competing managers. Most importantly, competition did not lead to the classic pattern of increased psychophysiological activation under competitive RSA-BF. Therefore, competition could facilitate the use of self-regulation strategies, especially in highly competitive individuals, to promote adaptive responses to psychological stress.

Neuromodulating Influence of Two Electroacupuncture Treatments on Heart Rate Variability, Stress, and Vagal Activity

Introduction: Although the clinical use of electro-acupuncture is widespread, the neuromodulating influence of various applied frequencies is not well established. Objectives: Heart rate variability (HRV), stress and parasympathetic recovery are closely related to health, longevity and vitality in humans. This study was undertaken to determine the influence of different electro-therapy frequencies on various autonomic nervous system markers when applied to a Battlefield Acupuncture Protocol (BFA). Design: A detailed comparison of autonomic nervous system (ANS) response to low frequency (LF) 2.5 Hz electro-acupuncture and mid-frequency (MF) 15 Hz electro-acupuncture applied by point stimulation to acupuncture points was undertaken on 2 groups of 12 patients. Interventions: Both LFEA and MFEA were applied to Battlefield Acupuncture protocol, consisting of five (5) key acupuncture ear (auricular) points that isolate the autonomic nervous system (ANS) and central nervous system's role in the chronic/acute pain cycle. Evaluations entailed an advanced status of autonomic nervous system (ANS) function through Electro-Cardiogram (ECG) baseline markers reflecting: sympathetic stress (SI); parasympathetic vagal tone (high frequency [HF]) and heart rate variability (HRV = total power). All were repeated subsequent to electro-therapy using 2 separate electro-modalities of low-frequency (2.5 Hz) electro-acupuncture (LFEA) and Mid-Frequency (15 Hz) electro-acupuncture (MFEA). All 24 patients received one (1) elector-acupuncture session. Results: The autonomic nervous system response to LFEA (2.5 Hz) reflected a statistically significant pre-post improvement in three of the markers collected: heart rate variability (HRV) improved by 61% [p = 0.002]; sympathetic stress (SI) reduced 42% [p = 0.002]; and parasympathetic vagal tone (HF) increased 56% [p = 0.017]. In contrast, MFEA (15 Hz) showed positive but non-significant changes in outcomes in all nervous system markers. Conclusions: The autonomic nervous system response with LFEA showed a measurable reduction in sympathetic stress with subsequent improvement in vagal tone, and HRV. This positive sympathetic nervous system deactivation from LFEA application shown in this study could have a major impact on other pathologies related to human health and longevity. Further cohort studies are warranted to determine the validity of these outcomes.

Effectiveness of Story-Centred Care Intervention Program in older persons living in long-term care facilities: A randomized, longitudinal study

Depression is a common issue in institutionalized elderly people. The “Attentively Embracing Story” theory is applied to help individuals transform negative thoughts into positive, and reflect on spiritual healing. This study aimed to examine the effectiveness of a “Story-Centred Care Intervention Program” based on the “Attentively Embracing Story” theory in improving depressive symptoms, cognitive function, and heart rate variability in institutionalized elderly people. Seventy long-term care residents were recruited from two long-term care facilities and randomized into the story-centred care intervention (n = 35) and control groups (n = 35). We excluded five long-term care residents who did not complete the post-test measures and five long-term care residents who had interference events on the outcome measures. Finally, sixty long-term care residents (40 women and 20 men; age 84.3±5.98 years) were included in the final analysis. Data were collected at four times (pre-intervention and post-intervention, 1 and 3-month follow-up) and analyzed with the generalized estimating equation approach.Instruments, including Geriatric Depression Scale, Short Portable Mind Status Questionnaire, and a CheckMyHeart device to measure heart rate variability, were used in study. The degree of improvement in depressive symptoms was significantly higher in the story-centred care intervention group than in the control group after providing the story-centred care intervention program (p < .001) and at 1 and 3-month follow-up (p = .001, p = .006, respectively; GDS-15 score reduced 1.816 at the 3-month follow-up). Participants receiving the story-centred care intervention program showed significantly greater improvement than those in the control group in the cognitive function at 1and 3-month follow-up (p = .009, p = .024, respectively; SPMSQ score reduced 0.345 at the 3-month follow-up). The heart rate variability parameters (SDNN, RMSSD) did not show a statistically significant increase. However an increasing trend in the parameters was observed in the intervention group (SDNN increased 16.235ms at the 3-month follow-up; RMSSD increased 16.424 ms at the 3-month follow-up). In conclusions, the story-centred care intervention program was effective on the improvement of depressive symptoms and cognitive status in institutionalized elderly people.

Impact of metoprolol treatment on cardiac function and exercise tolerance in heart failure patients with neuropsychiatric disorders

OBJECTIVE

To investigate the impact of neuropsychiatric disorders on the effect of metoprolol on cardiac and motor function in chronic heart failure (CHF) patients.

METHODS

From February 2013 to April 2016, CHF patients with clinical mental disorders received metoprolol (23.75 or 47.5 mg, once daily, orally) at the Second Affiliated Hospital of Kunming Medical University. Mental status was confirmed by means of the Hospital Anxiety and Depression Scale (HADS) and the Copenhagen Burnout Inventory (CBI) scale. Cardiac function parameters such as systolic blood pressure (SBP), ejection fraction (EF) and cardiac index (CI) as well as motor function including the 6 meter walk test (6MWT) and the Veteran's Specific Activity Questionnaire (VSAQ) were assessed as primary outcomes of the study.

RESULTS

A total of 154 patients (median age, 66.39 years; men, n = 101) were allocated into eight groups based on their mental status. There were no significant differences in heart rate (HR) or SBP control achieved by metoprolol in any groups compared with the control (patients with normal mental status). Furthermore, biphasic ejection fraction (EF) changes were observed in all the groups with a decrease in the first month and increase from the sixth month. However, this increase was significantly lower (p < .001) than the EF achieved with metoprolol treatment in the control group except for the anxiety group. A similar pattern was seen for CI, 6MWT and VSAQ changes in all the groups. Patients in the anxiety group responded similarly to the patients with normal mental status.

CONCLUSION

Depressive and high burnout symptoms, but not anxiety, lower the improvement of cardiac and motor function by metoprolol treatment in CHF.

Assessing mood symptoms through heartbeat dynamics: An HRV study on cardiosurgical patients

BACKGROUND

Heart Rate Variability (HRV) is reduced both in depression and in coronary heart disease (CHD) suggesting common pathophysiological mechanisms for the two disorders. Within CHD, cardiac surgery patients (CSP) with postoperative depression are at greater risk of adverse cardiac events. Therefore, CSP would especially benefit from depression early diagnosis. Here we tested whether HRV-multi-feature analysis discriminates CSP with or without depression and provides an effective estimation of symptoms severity.

METHODS

Thirty-one patients admitted to cardiac rehabilitation after first-time cardiac surgery were recruited. Depressive symptoms were assessed with the Center for Epidemiologic Studies Depression Scale (CES-D). HRV features in time, frequency, and nonlinear domains were extracted from 5-min-ECG recordings at rest and used as predictors of "least absolute shrinkage and selection" (LASSO) operator regression model to estimate patients' CES-D score and to predict depressive state.

RESULTS

The model significantly predicted the CES-D score in all subjects (the total explained variance of CES-D score was 89.93%). Also it discriminated depressed and non-depressed CSP with 86.75% accuracy. Seven of the ten most informative metrics belonged to non-linear-domain.

LIMITATIONS

A higher number of patients evaluated also with a structured clinical interview would help to generalize the present findings.

DISCUSSION

To our knowledge this is the first study using a multi-feature approach to evaluate depression in CSP. The high informative power of HRV-nonlinear metrics suggests their possible pathophysiological role both in depression and in CHD. The high-accuracy of the algorithm at single-subject level opens to its translational use as screening tool in clinical practice.

Longitudinal monitoring of heartbeat dynamics predicts mood changes in bipolar patients: A pilot study

OBJECTIVES

Recent research indicates that Heart Rate Variability (HRV) is affected in Bipolar Disorders (BD) patients. To determine whether such alterations are a mere expression of the current mood state or rather contain longitudinal information on BD course, we examined the potential influence of states adjacent in time upon HRV features measured in a target mood state.

METHODS

Longitudinal evaluation of HRV was obtained in eight BD patients by using a wearable monitoring system developed within the PSYCHE project. We extracted time-domain, frequency-domain and non-linear HRV-features and trained a Support Vector Machine (SVM) to classify HRV-features according to mood state. To evaluate the influence of adjacent mood states, we trained SVM with different HRV-feature sets: 1) belonging to each mood state considered alone; 2) belonging to each mood state and normalized using information from the preceding mood state; 3) belonging to each mood state and normalized using information from the preceding and subsequent mood states; 4) belonging to each mood state and normalized using information from two randomly chosen states.

RESULTS

SVM classification accuracy within a target state was significantly greater when HRV-features from the previous and subsequent mood states were considered.

CONCLUSIONS

Although preliminary and in need of replications our results suggest for the first time that psychophysiological states in BD contain information related to the subsequent ones. Such characteristic may be used to improve clinical management and to develop algorithms to predict clinical course and mood switches in individual patients.

Preoperative biomedical risk and depressive symptoms are differently associated with reduced health-related quality of life in patients 1year after cardiac surgery

OBJECTIVE

To examine whether preoperative biomedical risk and depressive symptoms were associated with physical and mental components of health-related quality of life (HRQoL) in patients 1year after cardiac surgery.

METHOD

Seventy-five patients completed a psychological evaluation, including the Center for Epidemiological Study of Depression scale, the 12-item Short-Form Physical Component Scale (SF-12-PCS) and Mental Component Scale (SF-12-MCS), the Instrumental Activities of Daily Living questionnaire for depressive symptoms and HRQoL, respectively, before surgery and at 1-year follow-up.

RESULTS

Preoperative depressive symptoms predicted the SF-12-PCS (beta=-.22, P<.05) and SF-12-MCS (beta=-.30, P<.04) scores in patients 1year after cardiac surgery, whereas the European System for Cardiac Operative Risk Evaluation was associated with SF-12-PCS (beta=-.28, P<.02), but not SF-12-MCS (beta=.01, P=.97) scores postoperatively.

CONCLUSIONS

The current findings showed that preoperative depressive symptoms are associated with poor physical and mental components of HRQoL, whereas high biomedical risk predicts reduced physical, but not mental, functioning in patients postoperatively. This study suggests that a preoperative assessment of depressive symptoms in addition to the evaluation of common biomedical risk factors is essential to anticipate which patients are likely to show poor HRQoL after cardiac surgery.

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.

Depression, anxiety and major adverse cardiovascular and cerebrovascular events in patients following coronary artery bypass graft surgery: a five year longitudinal cohort study

BACKGROUND

Although depression and anxiety have been implicated in risk for major adverse cardiovascular and cerebrovascular events (MACCE), a theoretical approach to identifying such putative links is lacking. The objective of this study was to examine the association between theoretical conceptualisations of depression and anxiety with MACCE at the diagnostic and symptom dimension level.

METHODS

Before coronary artery bypass graft (CABG) surgery, patients (N = 158; 20.9 % female) underwent a structured clinical interview to determine caseness for depression and anxiety disorders. Depression and anxiety disorders were arranged into the distress cluster (major depression, dysthymia, generalized anxiety disorder, post-traumatic stress disorder) and fear cluster (panic disorder, agoraphobia, social phobia). Patients also completed the self-report Mood and Anxiety Symptom Questionnaire, measuring anhedonia, anxious arousal and general distress/negative affect symptom dimensions. Incident MACCE was defined as fatal or non-fatal; myocardial infarction, unstable angina pectoris, repeat revascularization, heart failure, sustained arrhythmia, stroke or cerebrovascular accident, left ventricular failure and mortality due to cardiac causes. Time-to-MACCE was determined by hazard modelling after adjustment for EuroSCORE, smoking, body mass index, hypertension, heart failure and peripheral vascular disease.

RESULTS

In the total sample, there were 698 cumulative person years of survival for analysis with a median follow-up of 4.6 years (interquartile range 4.2 to 5.2 years) and 37 MACCE (23.4 % of total). After covariate adjustment, generalized anxiety disorder was associated with MACCE (hazard ratio [HR] = 2.79, 95 % confidence interval [CI] 1.00-7.80, p = 0.049). The distress disorders were not significantly associated with MACCE risk (HR = 2.14; 95 % CI .92-4.95, p = 0.077) and neither were the fear-disorders (HR = 0.24, 95 % CI .05-1.20, p = 0.083). None of the symptom dimensions were significantly associated with MACCE.

CONCLUSIONS

Generalized anxiety disorder was significantly associated with MACCE at follow-up after CABG surgery. The findings encourage further research pertaining to generalized anxiety disorder, and theoretical conceptualizations of depression, general distress and anxiety in persons undergoing CABG surgery.

Somatic, but not cognitive-affective, symptoms are associated with reduced heart rate variability in individuals with dysphoria

Background: Somatic, but not cognitive–affective, symptoms of depression have been associated with reduced heart rate variability (HRV), and with poor prognosis in cardiovascular patients. However, factors concomitant with cardiovascular diseases may confound the relationship between somatic symptoms of depression and reduced HRV. Therefore, this study examined whether reduced HRV was differentially associated with cognitive–affective and somatic symptoms of depression in medically healthy individuals with and without dysphoria.

Methods: Self-reported cognitive–affective and somatic symptoms as measured with the Beck Depression Inventory-II questionnaire and time and frequency domain parameters of HRV were collected in 62 medically healthy individuals, of whom 25 with and 37 without dysphoria.

Results: Somatic, but not cognitive–affective, symptoms of depression were inversely associated with SD of NN intervals (β = -0.476, p < 0.05), number of interval differences of successive NN intervals greater than 50 ms (NN50; β = -0.498, p < 0.03), and HRV total power (β = -0.494, p < 0.04) in the group with dysphoria, after controlling for sex, anxiety, and lifestyle factors. Cognitive–affective and somatic symptoms were not related to any of the HRV parameters in the group without dysphoria (all ps > 0.24).

Conclusion: By showing that the relationship between somatic depressive symptoms and reduced HRV extends to medically healthy individuals with dysphoria, the present findings suggest that this association is independent of factors concomitant with cardiovascular diseases. The present study also suggests that individuals with somatic rather than cognitive–affective subsets of depressive symptoms may be at greater risk for developing cardiovascular diseases.

Relationship between gastroesophageal reflux disease and psychological factors and autonomic nervous function

Gastroesophageal reflux disease (GERD) is a multifactorial disease. Psychological factors play an important role in the development and progression process and the treatment of GERD. Autonomic nervous dysfunction leads to changes of the digestive tract and high gastrointestinal sensitivity. Autonomic nerve function disorder is the intermediate link between psychological factors and gastroesophageal reflux symptoms in patients with GERD. Research on psychological factors and autonomic nervous function plays an important role in the clinical diagnosis and treatment of GERD in the future.

Depression is associated with increased vagal withdrawal during unpleasant emotional imagery after cardiac surgery

BACKGROUND

The aim of this study was to examine the influence of depression on heart rate and heart rate variability (HRV) during emotional imagery in patients after cardiac surgery.

METHODS

Based on the scores of the Center for Epidemiological Studies of Depression (CES-D) scale, 28 patients after cardiac surgery were assigned either to the group with depression (CES-D scores ≥ 16; N = 14) or the one without depression (CES-D scores<16; N = 14). Each patient completed a rest period and an emotional imagery including pleasant, neutral and unpleasant scripts. Inter-beat intervals (IBIs) and HRV were measured during the entire protocol.

RESULTS

Compared to nondepressed patients, those with depression had greater reductions in high frequency expressed in normalized units (HF n.u.) during the imaging of the unpleasant script (p = .003, Cohen's d = 1.34). Moreover, HF n.u. were lower during the imaging of the unpleasant script than the pleasant one in depressed patients only (p = .020, Cohen's d = 0.55). CES-D scores were also inversely correlated with residualized changes in IBIs (r = -.38, p = .045) and HF n.u. (r = -.49, p = .008) from rest to the imaging of the unpleasant script.

CONCLUSIONS

The relationship between depression and increased vagal withdrawal during unpleasant emotional imagery extends to patients after cardiac surgery. The present study suggests that increased vagal withdrawal to negative emotions in patients after cardiac surgery may mediate the conferral of cardiac risk by depression.

Breathing at a rate of 5.5 breaths per minute with equal inhalation-to-exhalation ratio increases heart rate variability

OBJECTIVES

Prior studies have found that a breathing pattern of 6 or 5.5 breaths per minute (bpm) was associated with greater heart rate variability (HRV) than that of spontaneous breathing rate. However, the effects of combining the breathing rate with the inhalation-to-exhalation ratio (I:E ratio) on HRV indices are inconsistent. This study aimed to examine the differences in HRV indices and subjective feelings of anxiety and relaxation among four different breathing patterns.

METHODS

Forty-seven healthy college students were recruited for the study, and a Latin square experimental design with a counterbalance in random sequences was applied. Participants were instructed to breathe at two different breathing rates (6 and 5.5 breaths) and two different I:E ratios (5:5 and 4:6). The HRV indices as well as anxiety and relaxation levels were measured at baseline (spontaneous breathing) and for the four different breathing patterns.

RESULTS

The results revealed that a pattern of 5.5 bpm with an I:E ratio of 5:5 produced a higher NN interval standard deviation and higher low frequency power than the other breathing patterns. Moreover, the four different breathing patterns were associated with significantly increased feeling of relaxation compared with baseline.

CONCLUSION

The study confirmed that a breathing pattern of 5.5 bpm with an I:E ratio of 5:5 achieved greater HRV than the other breathing patterns. This finding can be applied to HRV biofeedback or breathing training in the future.

Depression and reduced heart rate variability after cardiac surgery: the mediating role of emotion regulation

BACKGROUND

Heart rate variability (HRV), as an index of autonomic nervous system (ANS) functioning, is reduced by depression after cardiac surgery, but the underlying mechanisms of this relationship are poorly understood. Poor emotion regulation as a core symptom of depression has also been associated with altered ANS functioning. The present study aimed to examine whether emotion dysregulation could be a mediator of the depression-reduced HRV relationship observed after cardiac surgery.

METHODS

Self-reported emotion regulation and four-minute HRV were measured in 25 depressed and 43 nondepressed patients after cardiac surgery. Mediation analysis was conducted to evaluate emotion regulation as a mediator of the depression-reduced HRV relationship.

RESULTS

Compared to nondepressed patients, those with depression showed lower standard deviation of normal-to-normal (NN) intervals (p<.05), root mean square successive difference of NN intervals (p<.004), and number of interval differences of successive NN intervals greater than 50ms (NN50) (p<.05). Increased low frequency (LF) in normalized units (n.u.) and reduced high frequency (HF) n.u. were also found in depressed compared to nondepressed patients (p's<.01). Mediation analysis revealed that suppression of emotion-expressive behavior partially mediated the effect of depression on LF n.u. and HF n.u.

CONCLUSIONS

Results confirmed previous findings showing that depression is associated with reduced HRV, especially a reduced vagal tone and a sympathovagal imbalance, after cardiac surgery. This study also provides preliminary evidence that increased trait levels of suppression of emotion-expressive behavior may mediate the depression-related sympathovagal imbalance after cardiac surgery.

Age, stress, and isolation in older adults living with HIV

People living with HIV (PLWH) have increasingly longer life spans. This age group faces different challenges than younger PLWH, which may include increased stress and social isolation. The purpose of this study was to determine whether the age and sex of PLWH are associated with measures of physiologic stress, perceived stress, and social isolation. In this cross-sectional study, we enrolled 102 PLWH equally into four groups divided by age (younger or older than 50 years) and gender. Participants completed well-validated survey measurements of stress and isolation, and their heart rate variability over 60 minutes was measured by Holter monitor. The mean (SD) Perceived Stress Scale score was 17.4 (6.94), mean Visual Analog Stress Scale score was 3.51 (2.79), and mean Hawthorne Friendship Scale score, a measure of social isolation, was 17.03 (4.84). Mean heart rate variability expressed as the SD of successive N-N intervals was 65.47 (31.16) msec. In multivariable regression models that controlled for selected demographic variables, there was no relationship between the Perceived Stress Scale and age (coefficient = -0.09, p =-0.23) or female gender (coefficient = -0.12, p = 0.93); however, there was a modest relationship between female gender and stress using the Visual Analog Stress Scale (coefficient = 1.24, p = 0.05). Perceived Stress was negatively associated with the Hawthorne Friendship score (coefficient = -0.34, p = 0.05). Hawthorne Friendship score was positively associated with younger age (coefficient = 0.11, p = 0.02). Age was the only independent predictor of physiologic stress as measured by heart rate variability (coefficient = -1.3, p < 0.01). Our findings suggest that younger PLWH may experience more social isolation; however, age-related changes in heart rate variability do not appear to be related to perceived stress or social isolation. Future longitudinal research is required to more thoroughly understand this relationship and its impact on the health of PLWH.

Altered cardiac autonomic nervous function in depression

BACKGROUND

Depression is an independent risk factor for coronary artery disease. Autonomic instability may play a mediating or moderating role in this relationship; however this is not well understood. The objective of this study was to explore cardiac autonomic function and cardiac arrhythmia in depression, the correlation between depression severity and Heart Rate Variability (HRV) related indices, and the prevalence of arrhythmia.

METHODS

Individuals (n = 53) with major depression as assessed by the Diagnostic and Statistical Manual of Mental Disorders, who had a Hamilton Rating Scale for Depression (HAMD) score ≥20 and a Zung Self-Rating Depression Scale score > 53 were compared to 53 healthy individuals, matched for age and gender. Multichannel Electrocardiograph ECG-92C data were collected over 24 hours. Long-term changes in HRV were used to assess the following vagally mediated changes in autonomic tone, expressed as time domain indices: Standard deviation of the NN intervals (SDNN), standard deviation of 5 min averaged NN intervals (SDANN), Root Mean Square of the Successive Differences (RMSSD) and percentage of NN intervals > 50 ms different from preceding interval (pNN50). Pearson's correlations were conducted to explore the strength of the association between depression severity (using the SDS and HRV related indices, specifically SDNN and low frequency domain / high frequency domain (LF/HF)).

RESULTS

The values of SDNN, SDANN, RMSSD, PNN50 and HF were lower in the depression group compared to the control group (P<.05). The mean value of the LF in the depression group was higher than the in control group (P<.05). Furthermore the ratio of LF/HF was higher among the depression group than the control group (P<.05). A linear relationship was shown to exist between the severity of the depression and HRV indices. In the depression group, the prevalence of arrhythmia was significantly higher than in the control group (P<.05), particularly supraventricular arrhythmias.

CONCLUSIONS

Our findings suggest that depression is accompanied by dysfunction of the cardiac autonomic nervous system, and further, that depression severity is linked to severity of this dysfunction. Individuals with depression appear to be susceptible to premature atrial and/or ventricular disease.