Electrophysiological changes of cardiac function during antidepressant treatment

The cardiovascular safety of tricyclic antidepressants in overdose and in clinical use

Tricyclic antidepressants (TCAs) remain widely prescribed for depression and many other conditions. There may be important differences between individual TCA in regard to their overdose toxicity and their cardiac toxicity in clinical use. We conducted a systematic review to compare the toxicity of individual TCA in overdose and the risk of serious adverse cardiac events occurring with therapeutic doses. We used the fatal toxicity index (FTI) and case fatality ratio as markers of fatality in overdose, and hazard ratios or odds ratios for the risk of cardiovascular adverse events during normal clinical use. In all, 30 reports of mortality in overdose and 14 observational studies assessing the risk of cardiovascular adverse events in clinical use were included. FTI values were of the same order of magnitude (101-102) for all TCAs except lofepramine. Desipramine appears to be somewhat more likely than other TCAs to lead to death in overdose. Amitriptyline, clomipramine, dothiepin/dosulepin, doxepin, trimipramine and imipramine showed broadly similar toxicity and were usually reported to be less toxic than desipramine. Data on nortriptyline were contradictory. Lofepramine had the lowest risk of death in overdose. The rank order of overdose toxicity was broadly consistent between different FTI definitions and between markers used. With respect to the risk of cardiovascular events at clinically relevant exposure, amitriptyline, nortriptyline and lofepramine were associated with a greater risk of in-use cardiotoxicity. All measures of overdose toxicity were subject to external influences and confounding. The continued use of TCAs in depression and other conditions should be minimized when considering their undoubted toxicity in overdose and possible toxicity in normal clinical use.

Cardioprotective and renoprotective effects of venlafaxine on cisplatin-induced cardiotoxicity and nephrotoxicity in rats

AIM

The current work aims to demonstrate the potential defensive function of venlafaxine (VLF) in cardiotoxicity and nephrotoxicity caused by cisplatin (CP), that could be by modulating extracellular signal-regulated kinase (ERK)1/2 and nicotinamide adenine dinucleotide phosphate (NAPDH) oxidase NOX4 pathways.

MAIN METHODS

Five groups of rats were used, as follow: three control groups (control, carboxymethyl cellulose, and VLF), CP group got CP once (7 mg/kg, intraperitoneally, i.p.), and (CP+ VLF) group got CP once then after 1 h they got VLF {50 mg/kg daily, orally for 14 days}. At the end of the study; electrocardiogram (ECG) was recorded for anaesthized rats then blood samples and tissues were taken for biochemical and histopathological investigations. Caspase 3, a marker of cellular damage and apoptosis was detected by immunohistochemistry.

KEY FINDINGS

CP treatment significantly impaired cardiac functions as evidenced by changes in rats' ECG. Cardiac enzymes, renal markers and inflammatory markers were increased with decreased activities of the total antioxidant capacity, superoxide dismutase and glutathione peroxidase. Also, ERK1/2 and NOX4 were upregulated with histopathological and immunohistochemical alterations of heart and kidney. While, VLF markedly alleviated CP-induced functional cardiac abnormalities and improved ECG pattern. It reduced both cardiac and renal biomarkers, oxidative stress, proinflammatory cytokine with ERK1/2 and NOX4 downregulation, improved the histopathological and immunohistochemical changes induced by cisplatin in heart and kidney.

SIGNIFICANCE

VLF treatment impedes cardiotoxicity and nephrotoxicity caused by CP. This beneficial effect was mediated through reduction of oxidative stress, inflammation, and apoptosis by targeting the ERK1/2 and NOX4.

Heart Rate Variability: A Measure of Cardiovascular Health and Possible Therapeutic Target in Dysautonomic Mental and Neurological Disorders

Mental illness such as depression and anxiety as well as cerebrovascular disease are linked to impairment of neurocardiac function mediated by changes to the autonomic nervous system with increased sympathetic and decreased parasympathetic activity. Autonomic neurocardiac function can be evaluated by computing heart rate variability (HRV). Over the past decades, research has demonstrated the diagnostic value of HRV as independent predictor of cardiovascular mortality and as disease marker in progressive autonomic nervous system disorders such as Parkinson’s disease. Here we summarize our studies on HRV and its therapeutic modulation in the context of psychopharmacology as well as psychiatric and neurological disorders to honor the life of Professor Evgeny Vaschillo, the true pioneer of HRV research who sadly passed away on November 21st, 2020.

Acute cardiotoxicity following 'poppy seed tea' consumption

Insect damage to, and sub-optimal harvesting practices of the Papaver somniferum poppy are associated with contamination of its seeds with opium alkaloids. Consumption of poppy seeds has been linked to opium-like overdose symptoms, such as reduced consciousness and respiratory depression. However, acute cardiotoxicity secondary to ingestion of contaminated poppy seeds has not been reported previously. We report a case of a 21-year-old man who presented with severe biventricular dysfunction and cardiogenic shock following consumption of homemade poppy seed tea. We highlight the importance of prompt recognition of the myocardial effects of opiates along with the more common respiratory and neurological effects. In this case, the acute cardiotoxicity was fully reversed with high-dose naloxone, milrinone and noradrenaline. In addition, we recommend offering high-level care due to the possibility that specialist cardiac services may be required. Ergo, early transfer to an appropriate centre is recommended.

Antidepressants and Risk of Sudden Cardiac Death: A Network Meta-Analysis and Systematic Review

Background: Antidepressants are one of the most prescribed medications, particularly for patients with mental disorders. Nevertheless, there are still limited data regarding the risk of ventricular arrhythmia (VA) and sudden cardiac death (SCD) associated with these medications. Thus, we performed systemic review and meta-analysis to characterize the risks of VA and SCD among patients who used common antidepressants. Methods: A literature search for studies that reported risk of ventricular arrhythmias and sudden cardiac death in antidepressant use from MEDLINE, EMBASE, and Cochrane Database from inception through September 2020. A random-effects model network meta-analysis model was used to analyze the relation between antidepressants and VA/SCD. Surface Under Cumulative Ranking Curve (SUCRA) was used to rank the treatment for each outcome. Results: The mean study sample size was 355,158 subjects. Tricyclic antidepressant (TCA) patients were the least likely to develop ventricular arrhythmia events/sudden cardiac deaths at OR 0.24, 0.028–1.2, OR 0.32 (95% CI 0.038–1.6) for serotonin and norepinephrine reuptake inhibitors (SNRI), and OR 0.36 (95% CI 0.043, 1.8) for selective serotonin reuptake inhibitors (SSRI), respectively. According to SUCRA analysis, TCA was on a higher rank compared to SNRI and SSRI considering the risk of VA/SCD. Conclusion: Our network meta-analysis demonstrated the low risk of VA/SCD among patients using antidepressants for SNRI, SSRI and especially, TCA. Despite the relatively lowest VA/SCD in TCA, drug efficacy and other adverse effects should be taken into account in patients with mental disorders.

Genome-wide Association Study of Dimensional Psychopathology Using Electronic Health Records

BACKGROUND

Genetic studies of neuropsychiatric disease strongly suggest an overlap in liability. There are growing efforts to characterize these diseases dimensionally rather than categorically, but the extent to which such dimensional models correspond to biology is unknown.

METHODS

We applied a newly developed natural language processing method to extract five symptom dimensions based on the National Institute of Mental Health Research Domain Criteria definitions from narrative hospital discharge notes in a large biobank. We conducted a genome-wide association study to examine whether common variants were associated with each of these dimensions as quantitative traits.

RESULTS

Among 4687 individuals, loci in three of five domains exceeded a genome-wide threshold for statistical significance. These included a locus spanning the neocortical development genes RFPL3 and RFPL3S for arousal (p = 2.29 × 10^-8) and one spanning the FPR3 gene for cognition (p = 3.22 × 10^-8).

CONCLUSIONS

Natural language processing identifies dimensional phenotypes that may facilitate the discovery of common genetic variation that is relevant to psychopathology.

Risk of Ventricular Arrhythmia with Citalopram and Escitalopram: A Population-Based Study

Background

The risk of ventricular arrhythmia with citalopram and escitalopram is controversial. In this study we investigated the association between these two drugs and the risk of ventricular arrhythmia.

Methods

We conducted a population-based retrospective cohort study of older adults (mean age 76 years) from 2002 to 2012 in Ontario, Canada, newly prescribed citalopram (n = 137 701) or escitalopram (n = 38 436), compared to those prescribed referent antidepressants sertraline or paroxetine (n = 96 620). After inverse probability of treatment weighting using a propensity score, the baseline characteristics of the comparison groups were similar. The primary outcome was a hospital encounter with ventricular arrhythmia within 90 days of a new prescription, assessed using hospital diagnostic codes. The secondary outcome was all-cause mortality within 90 days.

Results

Citalopram was associated with a higher risk of a hospital encounter with ventricular arrhythmia compared with referent antidepressants (0.06% vs. 0.04%, relative risk [RR] 1.53, 95% confidence intervals [CI]1.03 to 2.29), and a higher risk of mortality (3.49% vs. 3.12%, RR 1.12, 95% CI 1.06 to 1.18). Escitalopram was not associated with a higher risk of ventricular arrhythmia compared with the referent antidepressants (0.03% vs. 0.04%, RR 0.84, 95% CI 0.42 to 1.68), but was associated with a higher risk of mortality (2.86% vs. 2.63%, RR 1.09, 95% CI 1.01 to 1.18).

Conclusion

Among older adults, initiation of citalopram compared to two referent antidepressants was associated with a small but statistically significant increase in the 90-day risk of a hospital encounter for ventricular arrhythmia.

Antidepressant and QT interval prolongation, how should we look at this issue? Focus on citalopram

INTRODUCTION

Evidence increasingly points to the potential development of harmful cardiac side effects concomitant with the use of a number of psychotropic drugs, primarily traditional antipsychotics and tricyclic antidepressants.

AREAS COVERED

The US Food and Drug Administration announced safety warnings associated with the use of citalopram with QT interval prolongation in 2011 and 2012. This paper explores the clinical background of QT interval prolongation, clinical data related to antidepressants and QT interval prolongation, the clinical implications of safety issues associated with the use of antidepressants and future research directions.

EXPERT OPINION

Currently available evidence proposes that citalopram may not be definitely associated with the increase of cardiac mortality, although it should be related with increase of QT prolongation. A firm consensus regarding the cardiac safety issues associated with antidepressants has to be established in near future. Hence, the choice of an individual antidepressant regarding cardiac safety issues should be based on multiple factors; clinicians may need to select the best available antidepressant for each individual based on that patient's vulnerability, the proven efficacy and safety of each agent and a reasonable benefit:risk ratio, based on currently available findings.

QT interval and antidepressant use: a cross sectional study of electronic health records

OBJECTIVE

To quantify the impact of citalopram and other selective serotonin reuptake inhibitors on corrected QT interval (QTc), a marker of risk for ventricular arrhythmia, in a large and diverse clinical population.

DESIGN

A cross sectional study using electrocardiographic, prescribing, and clinical data from electronic health records to explore the relation between antidepressant dose and QTc. Methadone, an opioid known to prolong QT, was included to demonstrate assay sensitivity.

SETTING

A large New England healthcare system comprising two academic medical centres and outpatient clinics.

PARTICIPANTS

38,397 adult patients with an electrocardiogram recorded after prescription of antidepressant or methadone between February 1990 and August 2011.

MAIN OUTCOME MEASURES

Relation between antidepressant dose and QTc interval in linear regression, adjusting for potential clinical and demographic confounding variables. For a subset of patients, change in QTc after drug dose was also examined.

RESULTS

Dose-response association with QTc prolongation was identified for citalopram (adjusted beta 0.10 (SE 0.04), P<0.01), escitalopram (adjusted beta 0.58 (0.15), P<0.001), and amitriptyline (adjusted beta 0.11 (0.03), P<0.001), but not for other antidepressants examined. An association with QTc shortening was identified for bupropion (adjusted beta 0.02 (0.01) P<0.05). Within-subject paired observations supported the QTc prolonging effect of citalopram (10 mg to 20 mg, mean QTc increase 7.8 (SE 3.6) ms, adjusted P<0.05; and 20 mg to 40 mg, mean QTc increase 10.3 (4.0) ms, adjusted P<0.01).

CONCLUSIONS

This study confirmed a modest prolongation of QT interval with citalopram, and identified additional antidepressants with similar observed risk. Pharmacovigilance studies using electronic health record data may be a useful method of identifying potential risk associated with treatments.

Risk of serious cardiovascular problems with medications for attention-deficit hyperactivity disorder

Attention-deficit hyperactivity disorder (ADHD) is a chronic neurodevelopmental disorder characterized by persistent symptoms of inattention, hyperactivity and/or impulsivity. The proportion of patients diagnosed with ADHD receiving pharmacological treatments has increased enormously in recent years. Despite the well established efficacy and the good safety and tolerability profile, there is concern about the potential for rare but serious cardiovascular adverse events, as well as sudden cardiac death, with pharmacotherapies used for treating ADHD in children, adolescents and adults. The present paper aims to comprehensively and critically review the published evidence on the controversial association between medications approved for treating patients with ADHD and the risk of serious cardiovascular problems, specifically the risk of corrected QT interval (QTc) prolongation, and the risk of sudden cardiac death. A comprehensive search of relevant databases (PubMed, EMBASE and PsychINFO) was conducted to identify studies published in peer-reviewed journals until 21 July 2012. Clinical reports, as well as retrospective or prospective population-based studies with children, adolescents or adults as participants, of pharmacotherapies for ADHD reporting cardiovascular adverse events were included. Stimulant medications for ADHD, including methylphenidate and amphetamine derivatives, are generally safe and well tolerated. Small but statistically significant increases in blood pressure (BP) and heart rate (HR) are among the adverse events of stimulant treatment in all age groups. Similarly, the non-stimulant medication atomoxetine has also been associated with increased HR and BP, although as is the case with stimulants, these are generally minor, time limited and of minor clinical significance in children, adolescents or adults. Growing evidence suggests that these medications do not cause sudden and unexpected cardiac death or serious cardiovascular problems including statistically or clinically significant increases in QTc, at therapeutic doses in ADHD patients across the lifespan. Small decreases in mean systolic BP, diastolic BP and HR have been observed in studies with guanfacine-extended release (-XR) or clonidine-XR, two α(2)-adrenergic receptor agonists, administered alone or in combination with psychostimulants to children and adolescents with ADHD. There are also no statistically or clinically significant increases in QTc associated with clonidine or guanfacine. There are no reports of torsades de pointes clearly and directly related to medications used for treating ADHD in patients of all age groups. The risk for serious cardiovascular adverse events, including statistically or clinically significant increases in QTc, and sudden cardiac death associated with stimulants, atomoxetine or α(2)-adrenergic agonists prescribed for ADHD is extremely low and the benefits of treating individual patients with ADHD, after an adequate assessment, outweigh the risks. However, great caution is advised when considering stimulant and non-stimulant medications for patients of any age with a diagnosis of ADHD and a personal or family history or other known risk factors for cardiovascular disease.

Antipsychotics and the Risks of Sudden Cardiac Death and All-Cause Death: Cohort Studies in Medicaid and Dually-Eligible Medicaid-Medicare Beneficiaries of Five States

CONTEXT

Antipsychotic drugs have been linked to QT-interval prolongation, a presumed marker of cardiac risk, and torsade de pointes.

OBJECTIVE

To examine the associations between antipsychotics and 1) outpatient-originated sudden cardiac death and ventricular arrhythmia (SD/VA) and 2) all-cause death.

DESIGN

Two retrospective cohort studies.

SETTING

Medicaid programs of California, Florida, New York, Ohio and Pennsylvania.

PATIENTS

Incident antipsychotic users aged 30-75 years.

MAIN OUTCOME MEASURES

1) Incident, first-listed emergency department or principal inpatient SD/VA diagnoses; and 2) death reported in the Social Security Administration Death Master File.

RESULTS

Among 459,614 incident antipsychotic users, the incidences of SD/VA and death were 3.4 and 35.1 per 1,000 person-years, respectively. Compared to olanzapine as the referent, adjusted hazard ratios (HRs) for SD/VA were 2.06 (95% CI, 1.20-3.53) for chlorpromazine, 1.72 (1.28-2.31) for haloperidol, and 0.73 (0.57-0.93) for quetiapine. Adjusted HRs for perphenazine and risperidone were consistent with unity. In a subanalysis limited to first prescription exposures, HRs for chlorpromazine and haloperidol were further elevated (2.54 [1.07-5.99] and 2.68 [1.59-4.53], respectively), with the latter exhibiting a dose-response relationship. Results for death were similar.

CONCLUSIONS

Haloperidol and chlorpromazine had less favorable cardiac safety profiles than olanzapine. Among atypical agents, risperidone had a similar cardiac safety profile to olanzapine, whereas quetiapine was associated with 30% and 20% lower risks of SD/VA and death, respectively, compared to olanzapine. These measured risks do not correlate well with average QT prolongation, further supporting the notion that average QT prolongation may be a poor surrogate of antipsychotic arrhythmogenicity.

Heart Rate Variability, Homeostasis, and Brain Function

Measures of heart rate variability (HRV) are major indices of the sympathovagal balance in cardiovascular research. These measures are thought to reflect complex patterns of brain activation as well and HRV is now emerging as a descriptor thought to provide information on the nervous system organization of homeostatic responses in accordance with the situational requirements. Current models of integration equate HRV to the affective states as parallel outputs of the central autonomic network, with HRV reflecting its organization of affective, physiological, “cognitive,” and behavioral elements into a homeostatic response. Clinical application is in the study of patients with psychiatric disorders, traumatic brain injury, impaired emotion-specific processing, personality, and communication disorders. HRV responses to highly emotional sensory inputs have been identified in subjects in vegetative state and in healthy or brain injured subjects processing complex sensory stimuli. In this respect, HRV measurements can provide additional information on the brain functional setup in the severely brain damaged and would provide researchers with a suitable approach in the absence of conscious behavior or whenever complex experimental conditions and data collection are impracticable, as it is the case, for example, in intensive care units.

The effects of antidepressants on human brain as detected by imaging studies. Focus on major depression

Recent brain imaging studies have shed light on understanding the pathogenesis of mood disorders. Evidence of structural, chemical, and functional brain changes, particularly in prefrontal cortex, cingulate, and amygdala, has been revealed in major depressive disorder (MDD). Furthermore, imaging techniques have been applied to monitor the effects of antidepressants (ADs) both in the brains of healthy volunteers and MDD patients. Although with some discrepancies due to the differences in study designs and patient samples, imaging findings have shown that ADs, particularly those having effects on the serotonergic system, modulate the volumes, functions and biochemistry of brain structures, i.e. dorsolateral prefrontal cortex, anterior cingulate and amygdala, which have been demonstrated abnormal in MDD by earlier imaging studies. This paper reviews imaging studies conducted in MDD patients and healthy controls treated with different ADs.

Antidepressants and the risk of sudden cardiac death and ventricular arrhythmia

PURPOSE

To examine the association between exposure to antidepressants and emergency department or inpatient admission for sudden cardiac death and ventricular arrhythmia (SD/VA), and to examine the impact of dose and cytochrome P-450 inhibition.

METHODS

A cohort study was conducted using 1999-2003 Medicaid claims data from beneficiaries of five large states, supplemented with Medicare claims for dually eligible individuals. Exposures were prescription claims for antidepressants of interest or a reference antidepressant. Outcomes were incident first-listed emergency department or principal inpatient diagnoses indicative of SD/VA originating in the outpatient setting, an outcome previously found to have a positive predictive value of 85%.

RESULTS

In 1.3 million person-years of antidepressant exposure, we identified 4222 SD/VA outcomes for a rate of 3.3/1000 person-years (95%CI, 3.2-3.4). Compared with paroxetine (a referent with a putatively favorable cardiovascular risk profile), adjusted hazard ratios (HRs) were 0.80 (0.67-0.95) for bupropion, 1.24 (0.93-1.65) for doxepin, 0.79 (0.55-1.15) for lithium, and 1.26 (1.11-1.42) for mirtazapine. HRs for amitriptyline, citalopram, fluoxetine, nefazodone, nortriptyline, sertraline, trazodone, and venlafaxine were near unity. For antidepressants having nonnull risks (bupropion and mirtazapine), we observed no relationship with antidepressant dose and some relationships with concomitant cytochrome P-450 inhibition.

CONCLUSIONS

Of antidepressants studied, only mirtazapine had a statistically significantly greater SD/VA risk versus paroxetine. However, baseline differences between these users suggest that this finding may be attributable to residual confounding. Eleven other antidepressants had SD/VA risks no greater than that of paroxetine, thereby providing reassurance regarding the comparative cardiovascular safety of antidepressants.

Patterned cardiomyocytes on microelectrode arrays as a functional, high information content drug screening platform

Cardiac side effects are one of the major causes of drug candidate failures in preclinical drug development or in clinical trials and are responsible for the retraction of several already marketed therapeutics. Thus, the development of a relatively high-throughput, high information content tool to screen drugs and toxins would be important in the field of cardiac research and drug development. In this study, recordings from commercial multielectrode arrays were combined with surface patterning of cardiac myocyte monolayers to enhance the information content of the method; specifically, to enable the measurement of conduction velocity, refractory period after action potentials and to create a functional re-entry model. Two drugs, 1-Heptanol, a gap junction blocker, and Sparfloxacin, a fluoroquinone antibiotic, were tested in this system. 1-Heptanol administration resulted in a marked reduction in conduction velocity, whereas Sparfloxacin caused rapid, irregular and unsynchronized activity, indicating fibrillation. As shown in these experiments, patterning of cardiac myocyte monolayers solved several inherent problems of multielectrode recordings, increased the temporal resolution of conduction velocity measurements, and made the synchronization of external stimulation with action potential propagation possible for refractory period measurements. This method could be further developed as a cardiac side effect screening platform after combination with human cardiomyocytes.

Reduced cardio-respiratory coupling after treatment with nortriptyline in contrast to S-citalopram

OBJECTIVE

Major depressive disorder is associated with increased cardiac mortality. A decrease in vagal modulation related to reduced heart rate variability might contribute to increased mortality among many other factors. We sought to examine the hypothesis that nortriptyline treatment will be associated with a decrease in heart rate variability and coupling between heart rate and respiration compared to treatment with S-citalopram.

METHODS

Fifty-two patients suffering from major depression were included. Patients were examined unmedicated in the acute stage and after 5weeks of treatment. Twenty-six were reinvestigated after they received S-citalopram and 26, after nortriptyline. We used non-linear measures of heart rate variability and also a novel measure to examine cardio-respiratory coupling to assess cardiac vagal modulation.

RESULTS

There were significant decreases of non-linear measures of heart rate variability in the nortriptyline group in addition to reduced cardio-respiratory coupling in comparison to the group of patients that received S-citalopram. We observed a significant association between the severity of the disease and vagal withdrawal prior to treatment.

CONCLUSIONS

These findings indicate that S-citalopram influences autonomic modulation on different regulatory levels to a lesser extent than nortriptyline. Our results have implications for treatment of patients with depression as some of them may already have a higher risk for cardiovascular mortality. In addition, it underlines the beneficial use of SSRIs in patients with cardiac diseases.

Impact of depression and antidepressant treatment on heart rate variability: a review and meta-analysis

BACKGROUND

Depression is associated with an increase in the likelihood of cardiac events; however, studies investigating the relationship between depression and heart rate variability (HRV) have generally focused on patients with cardiovascular disease (CVD). The objective of the current report is to examine with meta-analysis the impact of depression and antidepressant treatment on HRV in depressed patients without CVD.

METHODS

Studies comparing 1) HRV in patients with major depressive disorder and healthy control subjects and 2) the HRV of patients with major depressive disorder before and after treatment were considered for meta-analysis.

RESULTS

Meta-analyses were based on 18 articles that met inclusion criteria, comprising a total of 673 depressed participants and 407 healthy comparison participants. Participants with depression had lower HRV (time frequency: Hedges' g = -.301, p < .001; high frequency: Hedges' g = -.293, p < .001; nonlinear: Hedges' g = -1.955, p = .05; Valsalva ratio: Hedges' g = -.712, p < .001) than healthy control subjects, and depression severity was negatively correlated with HRV (r = -.354, p < .001). Tricyclic medication decreased HRV, although serotonin reuptake inhibitors, mirtazapine, and nefazodone had no significant impact on HRV despite patient response to treatment.

CONCLUSIONS

Depression without CVD is associated with reduced HRV, which decreases with increasing depression severity, most apparent with nonlinear measures of HRV. Critically, a variety of antidepressant treatments do not resolve these decreases despite resolution of symptoms, highlighting that antidepressant medications might not have HRV-mediated cardioprotective effects and the need to identify individuals at risk among patients in remission.

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

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

Abnormal nocturnal heart rate variability response among chronic kidney disease and dialysis patients during wakefulness and sleep

BACKGROUND

Dialysis patients and patients with chronic kidney disease (CKD) experience a substantial risk for abnormal autonomic function and abnormal heart rate variability (HRV). It remains unknown whether HRV changes across sleep stages in patients with different severity of CKD or dialysis dependency. We hypothesized that high-frequency (HF) HRV (vagal tone) will be attenuated from wakefulness to non-rapid eye movement (NREM) and then to rapid eye movement (REM) sleep in dialysis patients as compared to patients with CKD.

METHODS

In-home polysomnography was performed in 95 patients with stages 4-5 CKD or end-stage renal disease (ESRD) on haemodialysis (HD) or peritoneal dialysis (PD). HRV was measured using fast Fourier transform of interbeat intervals during wakefulness and sleep. Low-frequency (LF) and HF intervals were generated. Natural logarithm HF (LNHF) and the logarithm LF/HF ratio (sympathovagal tone) were analysed by multivariable quantile regression and generalized estimating equations.

RESULTS

Of the 95 patients, 63.2% (n = 60) was male, 35.8% (n = 34) was African American and 20.4% (n = 19) was diabetic. Average age was 51.6 ± 15.1 (range 19-82). HRV variables were significantly associated with diabetic status, higher periodic limb movement indices and lower bicarbonate levels. Patients with advanced CKD did not differ from dialysis patients in their inability to increase vagal tone during sleep. During wakefulness, female gender (P = 0.05) was associated with the increases in the vagal tone.

CONCLUSIONS

Patients with CKD/ESRD exhibit dysregulation of the autonomic nervous system tone manifesting as a failure to increase HRV during wakefulness and sleep. Different patient characteristics are associated with changes in HRV at different sleep stages.