Cardiovascular Complications of Sleep Disorders: A Better Night's Sleep for a Healthier Heart / From Bench to Bedside

Circadian (Diurnal/Nocturnal) Pattern of Cardiac Arrhythmias

Circadian rhythms follow 24-hour biological-cycle patterns controlled by internal biological or circadian clocks that optimize organismal homeostasis according to predictable environmental changes. These clocks are found in virtually all cells in the body, including cardiomyocytes. Triggers for and/or the occurrence of sudden cardiac death (SCD), and cardiac arrhythmias seem to follow such daily patterns. This review highlights data from studies exploring the role of day/night rhythms in the timing of arrhythmic events, studies describing the enviromental, behavioral and circadian mechanisms regulating cardiac electrophysiology focusing on the circadian pattern of arrhythmias and SCD. Mechanisms involved relate to circadian control of electrophysiological properties, vagal tone, and sleep disorders, as well as the potential interaction and synergism among these factors. By studying the diurnal variations of arrhythmias, therapy can be improved by optimally timing it to their circadian pattern and a person's internal body clock-time. Potential treatment targets for arrhythmias with nocturnal onset may include upstream therapy for underlying comorbidities, type and timing of drug intake, pulmonary vein isolation, ablation of the ganglionated plexus, and autonomic nervous system control. Thus, specific history taking, screening and diagnostic workup are recommended to identify and characterize comorbidities and potential contributors to nocturnal arrhythmias, such as obesity, advanced age, diabetes, hypertension and heart failure. In this direction, symptoms of sleep apnea may comprise snoring and excessive daytime sleepiness. Risk factors include obesity, decreased upper airway dimensions, and heart failure. Thus, one should have a low threshold for sleep testing to assess for sleep apnea. Sleep apnea treatment decreases ventricular arrhythmias and ameliorates some severe bradycardic episodes often obviating the need for pacemaker implantation. Importantly, comorbidity treatment and lifestyle optimization remain crucial.

Elucidating sleep disorders: a comprehensive bioinformatics analysis of functional gene sets and hub genes

Background

Sleep disorders (SD) are known to have a profound impact on human health and quality of life although their exact pathogenic mechanisms remain poorly understood.

Methods

The study first accessed SD datasets from the GEO and identified DEGs. These DEGs were then subjected to gene set enrichment analysis. Several advanced techniques, including the RF, SVM-RFE, PPI networks, and LASSO methodologies, were utilized to identify hub genes closely associated with SD. Additionally, the ssGSEA approach was employed to analyze immune cell infiltration and functional gene set scores in SD. DEGs were also scrutinized in relation to miRNA, and the DGIdb database was used to explore potential pharmacological treatments for SD. Furthermore, in an SD murine model, the expression levels of these hub genes were confirmed through RT-qPCR and Western Blot analyses.

Results

The findings of the study indicate that DEGs are significantly enriched in functions and pathways related to immune cell activity, stress response, and neural system regulation. The analysis of immunoinfiltration demonstrated a marked elevation in the levels of Activated CD4+ T cells and CD8+ T cells in the SD cohort, accompanied by a notable rise in Central memory CD4 T cells, Central memory CD8 T cells, and Natural killer T cells. Using machine learning algorithms, the study also identified hub genes closely associated with SD, including IPO9, RAP2A, DDX17, MBNL2, PIK3AP1, and ZNF385A. Based on these genes, an SD diagnostic model was constructed and its efficacy validated across multiple datasets. In the SD murine model, the mRNA and protein expressions of these 6 hub genes were found to be consistent with the results of the bioinformatics analysis.

Conclusion

In conclusion, this study identified 6 genes closely linked to SD, which may play pivotal roles in neural system development, the immune microenvironment, and inflammatory responses. Additionally, the key gene-based SD diagnostic model constructed in this study, validated on multiple datasets showed a high degree of reliability and accuracy, predicting its wide potential for clinical applications. However, limited by the range of data sources and sample size, this may affect the generalizability of the results.

Depression and atrial fibrillation in a reciprocal liaison: a neuro-cardiac link

OBJECTIVE

To explore the reciprocal relationship of depression and atrial fibrillation (AF).

METHODS

A literature search was conducted in Pub Med, Scopus, and Google Scholar using relevant terms for depression and AF and respective therapies.

RESULTS

There is evidence that depression is involved in the aetiology and prognosis of AF. AF, independently of its type, incurs a risk of depression in 20-40% of patients. Also, depression significantly increases cumulative incidence of AF (from 1.92% to 4.44% at 10 years); 25% increased risk of new-onset AF is reported in patients with depression, reaching 32% in recurrent depression. Hence, emphasis is put on the importance of assessing depression in the evaluation of AF and vice versa. Persistent vs paroxysmal AF patients may suffer from more severe depression. Furthermore, depression can impact the effectiveness of AF treatments, including pharmacotherapy, anticoagulation, cardioversion and catheter ablation.

CONCLUSIONS

A reciprocal association of depression and AF, a neurocardiac link, has been suggested. Thus, strategies which can reduce depression may improve AF patients' course and treatment outcomes. Also, AF has a significant impact on risk of depression and quality of life. Hence, effective antiarrhythmic therapies may alleviate patients' depressive symptoms. KEY POINTSAF, independently of its type of paroxysmal, permanent or chronic, appears to have mental besides physical consequences, including depression and anxietyA reciprocal influence or bidirectional association of depression and AF, a neurocardiac link, has been suggestedAF has considerable impact on the risk of depression occurrence with 20-40% of patients with AF found to have high levels of depressionAlso, depression significantly increases 10-year cumulative incidence and risk of AF from 1.92% to 4.44% in people without depression, and the risk of new-onset AF by 25-32%Emphasis should be placed on the importance of assessing depression in the evaluation of AF and vice versaPersistent/chronic AF patients may suffer from more severe depressed mood than paroxysmal AF patients with similar symptom burdenDepression and anxiety can impact the effectiveness of certain AF treatments, including pharmacotherapy, anticoagulation treatment, cardioversion and catheter ablationThus, strategies which can reduce anxiety and depression may improve AF patients' course and treatment outcomesAlso, effective antiarrhythmic therapies to control AF may alleviate patients' depressive mood.

Sleep traits and risk of end-stage renal disease: a mendelian randomization study

BACKGROUND

Epidemiological evidence relating sleep disorders to end-stage renal disease (ESRD) has been obscure. The present study is sought to examine the association between sleep traits and ESRD.

METHODS

For this analysis, we selected genetic instruments for sleep traits from published genome-wide association studies (GWAS). As instrumental variables, independent genetic variations linked with seven sleep-related features (sleep duration, getting up in the morning, daytime napping, chronotype of morning/evening person, sleeplessness/insomnia, non-snoring, and daytime dozing) were chosen. A two-sample Mendelian randomization (TSMR) study was conducted to assess the causal relationship between sleep traits and ESRD (N = 33,061). The reverse MR analysis subsequently determined the causal relationship between ESRD and sleep traits. The causal effects were estimated using inverse variance weighted, MR-Egger, weighted median. To conduct sensitivity studies, Cochran's Q test, MR-Egger intercept test, MR-PRESSO, leave-one-out analysis, and funnel plot were used. To study the potential mediators, multivariable mendelian randomization analyses were undertaken further.

RESULTS

Genetically predicted sleeplessness/ insomnia (OR = 6.11, 95%CI 1.00-37.3, P = 0.049, FDR = 0.105), getting up in the morning easily(OR = 0.23, 95%CI 0.063-0.85; P = 0.0278, FDR = 0.105), non-snoring (OR = 4.76E-02, 95%CI 2.29E-03-0.985, P = 0.0488, FDR = 0.105) was suggestively associated with the risk of ESRD. However, we found no evidence favoring a causal association between other sleep traits and ESRD through the IVW method.

CONCLUSION

The present TSMR found no strong evidence of a bidirectional causal association between genetically predicted sleep traits and ESRD.

Sleep duration, hypnotic drug use, and risk factors: cross- sectional study

Both short sleep duration (SSD) and long sleep duration (LSD) are associated with an increased risk of morbidity and mortality. Here, we aimed to assess the prevalence of sleep duration disturbances among adults in association with demographic, medication use, personal habits, and chronic diseases, while also considering the impact of hypnotic drug use. We performed a cross-sectional study of 9991 adult participants of the Rafsanjan Cohort Study (RCS), as part of the Prospective epidemiological research studies in Iran (PERSIAN). Multivariate logistic regression analyses were conducted to assess the association between short (< 6 h) and long (> 9 h) sleep duration with demographic and lifestyle parameters and common non-communicable diseases. Additionally, we performed stratified analysis to investigate the association of sleep duration with the abovementioned factors and diseases, in groups with and without hypnotic drug use. We found higher odds of SSD significantly associated with age (P < 0.001), BMI (P < 0.001), physical activity (P < 0.001), and depression (P = 0.023). LSD displayed a positive association with the female sex (P < 0.001), opium consumption (P < 0.001), and history of MI (P = 0.045), and a reverse connection with education (P = 0.007), physical activity (P < 0.001) and alcohol consumption (P = 0.027). Stratifying for the hypnotic drug use, our sensitivity analyses indicated that in hypnotic drug users, education (P = 0.034) and physical activity (P < 0.001) were associated with LSD, in this group, significantly increased odds ratio of LSD were associated with opium consumption (P = 0.046) and thyroid dysfunction (P = 0.037). Our findings demonstrated the demographic and lifestyle factors and diseases associated with long and short sleep duration in the population of the RCS. Additionally, after stratifying for hypnotic drug use, our results indicated that some diseases are only associated with abnormal sleep duration upon using hypnotic drugs.

LDL-cholesterol control in the primary prevention of cardiovascular diseases: An expert opinion for clinicians and health professionals

AIMS

Although adequate clinical management of patients with hypercholesterolemia without a history of known cardiovascular disease is essential for prevention, these subjects are often disregarded. Furthermore, the scientific literature on primary cardiovascular prevention is not as rich as that on secondary prevention; finally, physicians often lack adequate tools for the effective management of subjects in primary prevention and have to face some unsolved relevant issues. This document aims to discuss and review the evidence available on this topic and provide practical guidance.

DATA SYNTHESIS

Available algorithms and risk charts represent the main tool for the assessment of cardiovascular risk in patients in primary prevention. The accuracy of such an estimate can be substantially improved considering the potential contribution of some additional risk factors (C-reactive protein, lipoprotein(a), family history of cardiovascular disease) and conditions (environmental pollution, sleep quality, socioeconomic status, educational level) whose impact on the cardiovascular risk has been better understood in recent years. The availability of non-invasive procedures to evaluate subclinical atherosclerosis may help to identify subjects needing an earlier intervention. Unveiling the presence of these conditions will improve cardiovascular risk estimation, granting a more appropriate intervention.

CONCLUSIONS

The accurate assessment of cardiovascular risk in subjects in primary prevention with the use of algorithms and risk charts together with the evaluation of additional factors will allow physicians to approach each patient with personalized strategies, which should translate into an increased adherence to therapy and, as a consequence, a reduced cardiovascular risk.

Role of Vitamins in Cardiovascular Health: Know Your Facts-Part 2

Cardiovascular disease (CVD) is a major cause of morbidity/mortality world-wide, hence preventive interventions are crucial. Observational data showing beneficial CV effects of vitamin supplements, promoted by self-proclaimed experts, have led to ~50% of Americans using multivitamins; this practice has culminated into a multi-billion-dollar business. However, robust evidence is lacking, and certain vitamins might incur harm. This two-part review focuses on the attributes or concerns about specific vitamin consumption on CVD. The evidence for indiscriminate use of multivitamins indicates no consistent CVD benefit. Specific vitamins and/or combinations are suggested, but further supportive evidence is needed. Data presented in Part 1 indicated that folic acid and certain B-vitamins may decrease stroke, whereas niacin might raise mortality; beta-carotene mediates pro-oxidant effects, which may abate the benefits from other vitamins. In Part 2, data favor the anti-oxidant effects of vitamin C and the anti-atherogenic effects of vitamins C and E, but clinical evidence is inconsistent. Vitamin D may provide CV protection, but data are conflicting. Vitamin K appears neutral. Thus, there are favorable CV effects of individual vitamins (C/D), but randomized/controlled data are lacking. An important caveat regards the potential toxicity of increased doses of fat-soluble vitamins (A/D/E/K). As emphasized in Part 1, vitamins might benefit subjects who are antioxidant-deficient or exposed to high levels of oxidative-stress (e.g., diabetics, smokers, and elderly), stressing the importance of targeting certain subgroups for optimal results. Finally, by promoting CV-healthy balanced-diets, we could acquire essential vitamins and nutrients and use supplements only for specific indications.

Associations of siesta and total sleep duration with hypertension or cardiovascular diseases in middle-aged and older adults

BACKGROUND

Whether the ratio of siesta duration in the total sleep duration was associated with the occurrence of hypertension or cardiovascular diseases (CVDs) was unclear.

HYPOTHESIS

To explore the associations of siesta, and siesta ratio with hypertension or CVDs in middle-aged and older adults.

METHODS

This cohort study collected the data of 9247 middle-aged and older adults. The associations of siesta, and siesta ratio with hypertension were analyzed in 7619 participants while the associations of siesta, and siesta ratio with CVDs were analyzed in 8685 participants via univariate and multivariate logistic regression analysis.

RESULTS

Total sleep duration < 6 h (odd ratio [OR] = 1.168, 95% confidence interval [CI]: 1.023-1.335) and siesta ratios ≥ 0.4 (OR = 1.712, 95% CI: 1.129-2.594) were associated with increased risk of hypertension in middle-aged and older adults. Siesta ratio ≥ 0.4 was linked with higher risk of hypertension in males aged ≥ 60 years and total sleep duration < 6 h was correlated with elevated risk of hypertension in males < 60 years. The risk of CVDs was elevated in people with siesta duration < 0.5 h (OR = 2.053, 95% CI: 1.323-3.185). In females ≥60 years, the sleep duration at night < 6 h was associated with increased risk of CVDs. In females < 60 years, increased risk was observed in those with siesta duration < 0.5 h and sleep duration at night < 6 h.

CONCLUSION

Short sleep duration or high siesta ratio were associated with higher risk of hypertension. Short siesta duration, sleep duration at night or total sleep duration were correlated with an elevated risk of CVDs.

Increased sympathetic tone is associated with illness burden in bipolar disorder

BACKGROUND

We recently described an association between reduced heart rate variability (HRV) and illness burden in bipolar disorder (BD) using a novel Illness Burden Index (IBI). We aimed to further characterize this association by using spectral analyses to assess whether the IBI is also associated with autonomic imbalance in BD patients.

METHODS

In this cross-sectional study, 53 participants with BD wore a device for 24 h to assess association between HRV spectral measures and the IBI or each of its components (age of onset, number and type of previous episode(s), duration of the most severe episode, history of suicide attempts or psychotic symptoms during episodes, co-morbid psychiatric disorders, and family history). We ran both unadjusted models and models controlling for age, sex, years of education, marital status, BMI, pharmacotherapy, and baseline functional cardiovascular capacity.

RESULTS

HRV low-frequency (LF) normalized values were almost twice as high as published in healthy controls. Higher IBI was associated with higher LF and lower High Frequency (HF) values, resulting in a higher LF/HF ratio, indicating an increased sympathetic tone. Four individual components of the IBI were similarly associated with measures of increased sympathetic tone: earlier age of onset, number of depressive episodes, co-morbid anxiety disorders, and family history of suicide. Adjusted and unadjusted models had similar results.

LIMITATIONS

Our models used mean LF and HF and do not consider their dynamic variations over 24 h or phase of the illness.

CONCLUSIONS

Burden of illness is associated with increased sympathetic tone in patients with BD, putting them at risk for arrythmias and sudden death.

Vaccine-induced immune thrombotic thrombocytopenia after vaccination against Covid-19: A clinical dilemma for clinicians and patients

The coronavirus disease 2019 (Covid-19) pandemic has had devastating effects on public health worldwide, but the deployment of vaccines for Covid-19 protection has helped control the spread of SARS Coronavirus 2 (SARS-CoV-2) infection where they are available. The common side effects reported following Covid-19 vaccination were mostly self-restricted local reactions that resolved quickly. Nevertheless, rare vaccine-induced immune thrombotic thrombocytopenia (VITT) cases have been reported in some people being vaccinated against Covid-19. This review summarizes the thromboembolic events after Covid-19 vaccination and discusses its molecular mechanism, incidence rate, clinical manifestations and differential diagnosis. Then, a step-by-step algorithm for diagnosing such events, along with a management plan, are presented. In conclusion, considering the likeliness of acquiring severe SARS-CoV-2 infection and its subsequent morbidity and mortality, the benefits of vaccination outweigh its risks. Hence, if not already initiated, all governments should begin an effective and fast public vaccination plan to overcome this pandemic.

COVID-19 pandemic: demographic and clinical correlates of disturbed sleep among 6,041 Canadians

OBJECTIVES

Psychological burdens of the COVID-19 pandemic are likely to impact sleep negatively. We investigate prevalence and correlates of disturbed sleep among subscribers to Text4Hope a daily supportive text message program launched in Alberta to support residents to deal with stress, anxiety, and depression.

METHODS

A survey link was sent to Text4Hope subscribers to assess demographic and clinical variables, including disturbed sleep, stress, anxiety, and depression using the third question on the Patient Health Questionnaire-9 (PHQ-9), Perceived Stress Scale, Generalised Anxiety Disorder 7-item scale, and PHQ-9, respectively. Data were analysed using univariate and logistic regression analyses.

RESULTS

Overall, 6041 out of 32,805 Text4Hope subscribers completed the survey (18.4% response rate). Prevalence of disturbed sleep was 77.8%. Subscribers aged 41-60 years were twice as likely to present with sleep disturbance compared to individuals ≤25 years (OR 1.89, 95% CI: 1.27-2.81). Individuals with moderate/high anxiety and stress symptoms and those with passive death wish/suicidal ideation had higher probability for sleep disturbance [(OR 4.05, 95% CI: 3.33-4.93), (OR 2.42, 95% CI: 1.99-2.94), and (OR 2.39, 95% CI: 1.69-3.38)], respectively.

CONCLUSION

As the pandemic continues, more Canadians are likely to develop sleep problems, an important consideration for planning mental health services.KEY POINTSThis is the first study to examine the prevalence rates and demographic and clinical correlates of disturbed sleep in a large sample (n = 6041) of Canadians during the COVID-19 pandemic.Prevalence of disturbed sleep was high at 77.8%.Individuals aged 41-60 years were twice as likely to present with sleep disturbance compared to individuals ≤25 years (OR 1.89, 95% CI: 1.27-2.81).Individuals with moderate/high anxiety symptoms, moderate/high stress symptoms, and suicidal ideation/thoughts of self-harm had higher likelihood of developing sleep disturbance, compared to individuals lacking these symptoms [(OR 4.05, 95% CI: 3.33-4.93) and (OR 2.42, 95% CI: 1.98-2.94)], respectively.As the pandemic continues, with fear of multiple waves, more Canadians are likely to develop sleep problems, an important consideration for planning the provision of mental health services.

ADVERSE EFFECT OF INSOMNIA ON BLOOD LIPIDS IN PATIENTS WITH HYPERTENSION

Insomnia is a risk factor for the development of arterial hypertension, obesity, type 2 diabetes mellitus, cardiac rhythm disorders, and myocardial infarction. At the same time, insomnia is one of the most frequent non-cardiac complaints in patients with cardiovascular diseases. The aim of the work was to study the presence of possible relationships between insomnia and the level of blood lipids. Materials and methods. A cross-sectional study involving 118 patients was conducted. Criteria for inclusion in the study were age over 45 years, the presence of essential hypertension. All patients included the study underwent sampling of 7 ml of venous blood in the morning under fasting conditions. The content of total cholesterol (TCS), triglycerides (TG), high-density lipoprotein cholesterol (HDL CS) was determined by enzymatic method on a biochemical analyser Humalyzer 2000. The patient was interviewed by a pre-trained study doctor.  Results. In the article a relationship between total cholesterol, low-density lipoprotein cholesterol and the presence of insomnia has been established and proved by statistical model. The overall statistical model accuracy is 89.6 % and statistical significance p < 0.005. Accuracy of insomnia prediction is 85.7 % by level of total cholesterol (TCS) and patient interview data. Only one model with best accuracy exists and it was estimated at the article. Conclusions. Relationship between total cholesterol, low-density lipoprotein cholesterol and the presence of insomnia has been established and proved by statistical model. Accuracy of insomnia prediction is 85.7 % by level of total cholesterol (TCS) and patient interview data.

Self-care of heart failure patients: practical management recommendations from the Heart Failure Association of the European Society of Cardiology

Self-care is essential in the long-term management of chronic heart failure. Heart failure guidelines stress the importance of patient education on treatment adherence, lifestyle changes, symptom monitoring and adequate response to possible deterioration. Self-care is related to medical and person-centred outcomes in patients with heart failure such as better quality of life as well as lower mortality and readmission rates. Although guidelines give general direction for self-care advice, health care professionals working with patients with heart failure need more specific recommendations. The aim of the management recommendations in this paper is to provide practical advice for health professionals delivering care to patients with heart failure. Recommendations for nutrition, physical activity, medication adherence, psychological status, sleep, leisure and travel, smoking, immunization and preventing infections, symptom monitoring, and symptom management are consistent with information from guidelines, expert consensus documents, recent evidence and expert opinion.

The role of the autonomic nervous system in cardiac arrhythmias: The neuro-cardiac axis, more foe than friend?

The autonomic nervous system (ANS) with its two limbs, the sympathetic (SNS) and parasympathetic nervous system (PSNS), plays a critical role in the modulation of cardiac arrhythmogenesis. It can be both pro- and/or anti-arrhythmic at both the atrial and ventricular level of the myocardium. Intricate mechanisms, different for specific cardiac arrhythmias, are involved in this modulatory process. More data are available for the arrhythmogenic effects of the SNS, which, when overactive, can trigger atrial and/or ventricular "adrenergic" arrhythmias in susceptible individuals (e.g. in patients with paroxysmal atrial fibrillation-PAF, ventricular pre-excitation, specific channelopathies, ischemic heart disease or cardiomyopathies), while it can also negate the protective anti-arrhythmic drug effects. However, there is also evidence that PSNS overactivity may be responsible for triggering "vagotonic" arrhythmias (e.g. PAF, Brugada syndrome, idiopathic ventricular fibrillation). Thus, a fine balance is necessary to attain in these two limbs of the ANS in order to maintain eurhythmia, which is a difficult task to accomplish. Over the years, in addition to classical drug therapies, where beta-blockers prevail, several ANS-modulating interventions have been developed aiming at prevention and management of arrhythmias. Among them, techniques of cardiac sympathetic denervation, renal denervation, vagal stimulation, ganglionated plexi ablation and the newer experimental method of optogenetics have been employed. However, in many arrhythmogenic diseases, ANS modulation is still an investigative tool. Initial data are encouraging; however, further studies are needed to explore the efficacy of such interventions. These issues are herein reviewed and old and recent literature data are discussed, tabulated and pictorially illustrated.