Linking Atrial Fibrillation with Alzheimer's Disease: Epidemiological, Pathological, and Mechanistic Evidence

Coffee Consumption Correlates With Better Cognitive Performance in Patients With a High Incidence for Stroke

BACKGROUND

Atrial fibrillation is an independent risk factor for the development of cognitive impairments. Regular coffee consumption has shown cognitive benefits in healthy individuals. Whether regular consumption reduces cognitive decline in vulnerable patients is controversial. We investigated the association in elderly people with atrial fibrillation.

METHODS AND RESULTS

Daily coffee consumption was assessed using a structured nutrition questionnaire, and cognitive function was evaluated by a detailed neurocognitive-test-battery, including the Montreal Cognitive Assessment, Trail-Making Test, semantic fluency, and Digit-Symbol-Substitution Test. The cognitive construct score combines all neurocognitive tests mentioned and provides an overall cognitive performance indicator. Hs-CRP (high-sensitivity C-reactive protein) and IL-6 (interleukin-6) were measured to explore an association with inflammation. Results were estimated using linear mixed-effects-models with detailed adjustments for confounders. The <1 cup/day consumers (reference group) reached a cognitive construct score of -0.24 (95% CI, -0.27 to -0.16), and the group with the highest consumption (>5 cups/day) was at -0.10 (95% CI, -0.10 to 0.04; p=0.048). Montreal Cognitive Assessment score in the reference group was 24.58 (95% CI, 24.58-25.32); the group with the highest intake achieved 25.25 (95% CI, 24.98-26.85; p=0.163). Inflammatory markers decreased with higher coffee consumption (hs-CRP with 5 compared with <1 cup/day by factor 0.78 [95% CI, 0.54-1.13], p= 0.188, IL-6 significantly by factor 0.73 [95% CI, 0.57-0.95], p=0.017).

CONCLUSIONS

Coffee consumption in patients with atrial fibrillation may be associated with improved cognitive performance and reduced inflammatory markers. Further research is needed to confirm these findings and to consider implementation in dietary counseling for atrial fibrillation management.

REGISTRATION

URL: https://www.clinicaltrials.gov; Identifier: NCT02105844.

Impact of depression and cardiovascular risk factors on cognitive impairment in patients with atrial fibrillation: A Systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) is a common cardiac arrhythmia associated with significant cardiovascular morbidity and mortality, as well as cognitive impairment (CI). The interplay between AF and CI is complex, involving various pathophysiological changes and numerous risk factors. Among them, depression has emerged as a significant contributor to both AF and CI, further complicating the relationship between these conditions.

OBJECTIVES

This systematic review and meta-analysis aimed to investigate the influence of depression on the development of cognitive impairment in AF patients and assess the predictive value of the CHA2DS2-VASc score for CI risk.

METHODS

We searched PubMed, Scopus, and Web of Science for relevant studies without language or date restrictions. Ten studies, comprising 1,605,577 participants, were included. A random-effects model was used for meta-analysis, and heterogeneity was assessed using I2 statistics. Funnel plots and Egger's test evaluated publication bias.

RESULTS

Depression significantly increased the risk of CI in AF patients (OR: 2.23, 95 % CI: 1.54-3.21, p < 0.01; I2=99 %). This association persisted in studies excluding baseline CI (OR: 1.95, 95 % CI: 1.33-2.85, p < 0.01; I2=88 %). Subgroup analysis confirmed these results for both prospective (OR: 1.78, 95 % CI: 0.92-3.44, p = 0.02; I2=65 %) and retrospective studies (OR: 2.63, 95 % CI: 1.75-3.93, p < 0.01; I2=100 %). Analysis of CHA2DS2-VASc risk factors showed associations with CI, particularly cerebrovascular disease (OR: 1.86, 95 % CI: 1.61-2.16).

CONCLUSIONS

Our findings support the association between depression and cognitive impairment in AF patients, demonstrating the importance of addressing mental health in cardiovascular care. Future research is necessary for a comprehensive understanding of this association.

Association between Atrial Fibrillation and Risk of Alzheimer's Disease and Vascular Dementia: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Recent research suggests that atrial fibrillation (AF) may influence the risk of developing Alzheimer's disease (AD) and vascular dementia (VaD). However, existing studies have provided inconsistent results, with some showing a significant association between AF and the risk of AD and VaD, while others do not. The objective of this study is to conduct a meta-analysis to investigate the association between AF and the risk of AD and VaD.

METHODS

A comprehensive search was conducted in several databases, including PubMed, Web of Science, Embase, and Google Scholar, covering research published before December 2023. Odds ratios (ORs) or relative risks (RRs) and 95% confidence intervals (CIs) were calculated using Stata 12.0 software to assess the association between AF and the risk of AD or VaD.

RESULTS

The meta-analysis revealed a significant association between AF and an increased risk of AD, using a random effects model (OR/RR: 1.23, 95% CI: 1.13-1.34, I2 = 81.3%, P < 0.001). Similarly, a significant association was found between AF and an increased risk of VaD, using a random effects model (OR/RR: 1.80, 95% CI: 1.57-2.07, I2 = 82.1%, P < 0.001).

CONCLUSION

In summary, our comprehensive meta-analysis provides compelling evidence of a significant association between AF and an elevated risk of AD and VaD. The findings are corroborated by robust cross-sectional and longitudinal cohort studies, which further validate the observed link. However, further large-scale prospective studies are necessary to comprehensively investigate the relationship between AF and the risk of AD and VaD.

Investigating the Interplay between Cardiovascular and Neurodegenerative Disease

Neurological diseases, including neurodegenerative diseases (NDDs), are the primary cause of disability worldwide and the second leading cause of death. The chronic nature of these conditions and the lack of disease-modifying therapies highlight the urgent need for developing effective therapies. To accomplish this, effective models of NDDs are required to increase our understanding of underlying pathophysiology and for evaluating treatment efficacy. Traditionally, models of NDDs have focused on the central nervous system (CNS). However, evidence points to a relationship between systemic factors and the development of NDDs. Cardiovascular disease and related risk factors have been shown to modify the cerebral vasculature and the risk of developing Alzheimer's disease. These findings, combined with reports of changes to vascular density and blood-brain barrier integrity in other NDDs, such as Huntington's disease and Parkinson's disease, suggest that cardiovascular health may be predictive of brain function. To evaluate this, we explore evidence for disruptions to the circulatory system in murine models of NDDs, evidence of disruptions to the CNS in cardiovascular disease models and summarize models combining cardiovascular disruption with models of NDDs. In this study, we aim to increase our understanding of cardiovascular disease and neurodegeneration interactions across multiple disease states and evaluate the utility of combining model systems.

INTEGRATING MENDELIAN RANDOMIZATION WITH CAUSAL MEDIATION ANALYSES FOR CHARACTERIZING DIRECT AND INDIRECT EXPOSURE-TO-OUTCOME EFFECTS

Mendelian randomization (MR) assesses the total effect of exposure on outcome. With the rapidly increasing availability of summary statistics from genome-wide association studies (GWASs), MR leverages existing summary statistics and is widely used to study the causal effects among complex traits and diseases. The total effect in the population is a sum of indirect and direct effects. For complex disease outcomes with complicated etiologies, and/or for modifiable exposure traits, there may exist more than one pathway between exposure and outcome. The direct effect and the indirect effect via a mediator of interest could be of opposite directions, and the total effect estimates may not be informative for treatment and prevention decision-making or may be even misleading for different subgroups of patients. Causal mediation analysis delineates the indirect effect of exposure on outcome operating through the mediator and the direct effect transmitted through other mechanisms. However, causal mediation analysis often requires individual-level data measured on exposure, outcome, mediator and confounding variables, and the power of the mediation analysis is restricted by sample size. In this work, motivated by a study of the effects of atrial fibrillation (AF) on Alzheimer's dementia, we propose a framework for Integrative Mendelian randomization and Mediation Analysis (IMMA). The proposed method integrates the total effect estimates from MR analyses based on large-scale GWASs with the direct and indirect effect estimates from mediation analysis based on individual-level data of a limited sample size. We introduce a series of IMMA models, under the scenarios with or without exposure-mediator interaction and/or study heterogeneity. The proposed IMMA models improve the estimation and the power of inference on the direct and indirect effects in the population, as well as the characterization of the variation of effects. Our analyses showed a significant positive direct effect of AF on Alzheimer's dementia risk not through the use of the oral anticoagulant treatment and a significant indirect effect of AF-induced anticoagulant treatment in reducing Alzheimer's dementia risk. The results suggested potential Alzheimer's dementia risk prediction and prevention strategies for AF patients, and paved the way for future re-evaluation of anticoagulant treatment guidelines for AF patients. A sensitivity analysis was conducted to assess the sensitivity of the conclusions to a key assumption of the IMMA approach.

Association between new-onset atrial fibrillation and dementia among individuals with type 2 diabetes

AIM

To assess the association between new-onset atrial fibrillation and dementia among patients with type 2 diabetes, a group with a high prevalence of atrial fibrillation.

MATERIALS AND METHODS

This cohort study included 22 989 patients with type 2 diabetes from the UK Biobank. New-onset atrial fibrillation was ascertained from hospital admission records. We used an algorithm officially released by the UK Biobank to identify all-cause dementia, Alzheimer's disease and vascular dementia. The algorithm was developed using multiple sources, including hospital admissions and the death registry. Time-varying Cox regression analyses were performed to investigate the association between new-onset atrial fibrillation and dementia.

RESULTS

A total of 2843 participants developed atrial fibrillation, whereas the remaining 20 146 did not. During the median of 12.3 years of follow-up, 844 all-cause dementia, 342 Alzheimer's disease and 246 vascular dementia cases occurred. Compared with participants without atrial fibrillation, those with atrial fibrillation had higher risks of all-cause dementia (hazard ratio [HR] 2.15, 95% confidence interval [CI] 1.80-2.57), Alzheimer's disease (HR 1.44, 95% CI 1.06-1.96) and vascular dementia (HR 3.11, 95% CI 2.32-4.17).

CONCLUSIONS

New-onset atrial fibrillation was associated with a substantially higher risk of all-cause dementia, Alzheimer's disease and vascular dementia in patients with type 2 diabetes. Our findings highlight the significance of atrial fibrillation management in mitigating the risk of dementia in this demographic.

Atrial Fibrillation and Cognitive Disorders

The prevalence of atrial fibrillation among older adults is increasing. Research has indicated that atrial fibrillation is linked to cognitive impairment disorders such as Alzheimer and vascular dementia, as well as Parkinson disease. Various mechanisms are believed to be shared between atrial fibrillation and cognitive impairment disorders. The specific pathologies and mechanisms of different cognitive disorders are still being studied. Potential mechanisms include cerebral hypoperfusion, ischemic or hemorrhagic infarction, and cerebrovascular reactivity to carbon dioxide. Additionally, circulatory biomarkers and certain infectious organisms appear to be involved. This review offers an examination of the overlapping epidemiology between atrial fibrillation and cognitive disorders, explores different cognitive disorders and their connections with this arrhythmia, and discusses trials and guidelines for preventing and treating atrial fibrillation in patients with cognitive disorders. It synthesizes existing knowledge on the management of atrial fibrillation and identifies areas that require further investigation to bridge the gap in understanding the complex relationship between dementia and atrial fibrillation.

Fibrinaloid Microclots and Atrial Fibrillation

Atrial fibrillation (AF) is a comorbidity of a variety of other chronic, inflammatory diseases for which fibrinaloid microclots are a known accompaniment (and in some cases, a cause, with a mechanistic basis). Clots are, of course, a well-known consequence of atrial fibrillation. We here ask the question whether the fibrinaloid microclots seen in plasma or serum may in fact also be a cause of (or contributor to) the development of AF. We consider known 'risk factors' for AF, and in particular, exogenous stimuli such as infection and air pollution by particulates, both of which are known to cause AF. The external accompaniments of both bacterial (lipopolysaccharide and lipoteichoic acids) and viral (SARS-CoV-2 spike protein) infections are known to stimulate fibrinaloid microclots when added in vitro, and fibrinaloid microclots, as with other amyloid proteins, can be cytotoxic, both by inducing hypoxia/reperfusion and by other means. Strokes and thromboembolisms are also common consequences of AF. Consequently, taking a systems approach, we review the considerable evidence in detail, which leads us to suggest that it is likely that microclots may well have an aetiological role in the development of AF. This has significant mechanistic and therapeutic implications.

Atrial Fibrillation and Dementia: Focus on Shared Pathophysiological Mechanisms and Therapeutic Implications

OBJECTIVES

Atrial fibrillation (AF) and dementia are highly prevalent chronic and debilitating conditions, especially affecting the older population. This review focuses on possible common pathophysiological mechanisms that could explain the association between the 2 conditions.

DESIGN

Narrative review.

SETTING AND PARTICIPANTS

Evidence from epidemiologic, observational, and interventional studies evaluating prevalence and incidence of cognitive impairment in patients with AF.

METHODS

Broad literature search between December 2022 and May 2023. Eligible categories for inclusion comprised interventional studies, observational studies, systematic reviews, and meta-analysis.

RESULTS

Evidence from different cohorts has shown that AF increases the risk of dementia, although the association with dementia subtypes is not always unequivocal. According to recent evidence, common pathophysiological mechanisms include thromboembolism and hypercoagulable states, proinflammatory state, infection, cerebral hypoperfusion, and brain atrophy. Moreover, we reviewed the evidence on therapeutic measures to prevent dementia in patients with AF.

CONCLUSIONS AND IMPLICATIONS

Screening for cognition in patients with AF is of paramount importance, given the shared risk factors and common pathophysiological mechanisms. More evidence is needed to clarify whether antiarrhythmic and anticoagulant therapy have an impact on cognitive outcomes in AF patients.

Associations between cardiometabolic multimorbidity and cerebrospinal fluid biomarkers of Alzheimer's disease pathology in cognitively intact adults: the CABLE study

BACKGROUND

Cardiometabolic multimorbidity is associated with an increased risk of dementia, but the pathogenic mechanisms linking them remain largely undefined. We aimed to assess the associations of cardiometabolic multimorbidity with cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) pathology to enhance our understanding of the underlying mechanisms linking cardiometabolic multimorbidity and AD.

METHODS

This study included 1464 cognitively intact participants from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) database. Cardiometabolic diseases (CMD) are a group of interrelated disorders such as hypertension, diabetes, heart diseases (HD), and stroke. Based on the CMD status, participants were categorized as CMD-free, single CMD, or CMD multimorbidity. CMD multimorbidity is defined as the coexistence of two or more CMDs. The associations of cardiometabolic multimorbidity and CSF biomarkers were examined using multivariable linear regression models with demographic characteristics, the APOE ε4 allele, and lifestyle factors as covariates. Subgroup analyses stratified by age, sex, and APOE ε4 status were also performed.

RESULTS

A total of 1464 individuals (mean age, 61.80 years; age range, 40-89 years) were included. The markers of phosphorylated tau-related processes (CSF P-tau181: β = 0.165, P = 0.037) and neuronal injury (CSF T-tau: β = 0.065, P = 0.033) were significantly increased in subjects with CMD multimorbidity (versus CMD-free), but not in those with single CMD. The association between CMD multimorbidity with CSF T-tau levels remained significant after controlling for Aβ42 levels. Additionally, significantly elevated tau-related biomarkers were observed in patients with specific CMD combinations (i.e., hypertension and diabetes, hypertension and HD), especially in long disease courses.

CONCLUSIONS

The presence of cardiometabolic multimorbidity was associated with tau phosphorylation and neuronal injury in cognitively normal populations. CMD multimorbidity might be a potential independent target to alleviate tau-related pathologies that can cause cognitive impairment.

Autonomic nervous system dysfunction throughout menopausal transition: A potential mechanism underpinning cardiovascular and cognitive alterations during female ageing

Cardiovascular diseases (CVD) and neurodegenerative disorders, such as Alzheimer's disease (AD), are highly prevalent conditions in middle-aged women that severely impair quality of life. Recent evidence suggests the existence of an intimate cross-talk between the heart and the brain, resulting from a complex network of neurohumoral circuits. From a pathophysiological perspective, the higher prevalence of AD in women may be explained, at least in part, by sex-related differences in the incidence/prevalence of CVD. Notably, the autonomic nervous system, the main heart-brain axis physiological orchestrator, has been suggested to play a role in the incidence of adverse cardiovascular events in middle-aged women because of decreases in oestrogen-related signalling during transition into menopause. Despite its overt relevance for public health, this hypothesis has not been thoroughly tested. Accordingly, in this review, we aim to provide up to date evidence supporting how changes in circulating oestrogen levels during transition to menopause may trigger autonomic dysfunction, thus promoting cardiovascular and cognitive decline in women. A main focus on the effects of oestrogen-mediated signalling at CNS structures related to autonomic regulation is provided, particularly on the role of oestrogens in sympathoexcitation. Improving the understanding of the contribution of the autonomic nervous system on the development, maintenance and/or progression of both cardiovascular and cognitive dysfunction during the transition to menopause should help improve the clinical management of elderly women, with the outcome being an improved life quality during the natural ageing process.

Cardiovascular and Neurological Outcomes in Patients Treated with Edoxaban for Atrial Fibrillation and Characteristics in Patients with Cancer

BACKGROUND

Direct oral anticoagulants (DOACs) outperform warfarin in vascular and bleeding events in atrial fibrillation (AF) patients. Yet, effects of DOACs on congestive heart failure (CHF) and Alzheimer's disease (AD) remain less explored.

METHODS

Using the Taiwan National Health Insurance Research Database, a nationwide retrospective cohort study was conducted. The study matched 5,683 non-valvular atrial fibrillation (NVAF) edoxaban patients with 11,366 warfarin patients, and 703 NVAF with cancer (NVAF-C) edoxaban patients with 1,406 warfarin patients. Vasular and non-vascular outcomes, with focuses on CHF and AD, were compared between the edoxaban and warfarin users.

RESULTS

Edoxaban significantly lowered adjusted hazrad ratio (aHR) of all-cause mortality, hospitalization for gastrointestinal bleeding, and CHF (0.37, 0.74, and 0.26, respectively, in NVAF; 0.39, 0.67, and 0.31, respectively, in NVAF-C, all p < 0.05), compared to warfarin. Edoxaban was associated with significantly lower aHRs of acute myocardial infarction, peripheral artery disease, venous thromboembolism, pulmonary embolism, and AD (0.71, 0.48, 0.55, 0.20, and 0.66, respectively; all p < 0.05) in NVAF patients versus warfarin. However, edoxaban had higher aHR of hospitalized bleeding (1.19, p = 0.002) than warfarin in NVAF patients, but not in NVAF-C patients.

CONCLUSIONS

Edoxaban demonstrated lowered CHF risks in both NVAF and NVAF-C patients, and reduced AD occurrence in NVAF patients versus warfarin. These findings advocate for edoxaban's use in AF cases.

CLINICAL PERSPECTIVE

What Is New?: The study reveals that in patients with atrial fibrillation (AF), edoxaban, a direct oral anticoagulant (DOAC), demonstrates significant advantages over warfarin. Notably, edoxaban is associated with a reduced risk of congestive heart failure (CHF) and Alzheimer's disease (AD) when compared to warfarin.Clinical Implications?: These findings have important clinical implications. Edoxaban appears to be a superior anticoagulant choice for AF patients, as it lowers the risk of CHF and AD. This highlights the potential of edoxaban to improve patient outcomes and underscores its relevance for managing AF cases.

Risk factor profile for newly diagnosed atrial fibrillation: 4-year follow-up of annual health examinations in a Japanese Adult Cohort

Background

Detecting unknown atrial fibrillation (AF) would provide an opportunity to prevent ischemic stroke by instituting appropriate anticoagulation. Although opportunistic screening of older patients is recommended in current guidelines, which patients may benefit from intensive AF screening remains unclear. We sought to clarify the risk factor profile for newly diagnosed AF in annual health examinations of a Japanese adult cohort.

Methods

Among 141 441 Japanese patients who underwent annual health examinations in 2014, 87 872 patients aged ≥20 years without known AF who had undergone electrocardiography were analyzed (mean age: 47 ± 12 years; 64% men). The absence of known AF was confirmed by prior electrocardiography in 2012 and/or 2013. Newly diagnosed AF was observed in 244 patients in 2014-2017 (mean age: 62 ± 12 years; 83% men).

Results

In the multivariable analysis, waist circumference obesity (hazard ratio [HR], 1.5; 95% confidence interval [CI], 1.13-1.99; p = .005) high blood pressure (HR, 1.9; 95% CI, 1.01-3.59; p = .047), on-treatment hypertension (HR, 1.53; 95% CI, 1.01-2.31; p = .046), and daily alcohol drinking (HR, 2.18; 95% CI, 1.52-3.12; p < .001) were significantly associated with newly diagnosed AF.

Conclusions

In this Japanese cohort, waist circumference obesity, hypertension, and alcohol drinking were independent predictors of newly diagnosed AF in annual medical examinations. This finding encourages further evaluation of systematic AF screening programs in at-risk populations.

Amyloid β induces cardiac dysfunction and neuro-signaling impairment in the heart of an Alzheimer's disease model

Aims

Alzheimer's disease (AD) is a complex neurodegenerative disorder characterized by cerebral amyloid β (Aβ) deposition and tau pathology. The AD-mediated degeneration of the brain neuro-signaling pathways, together with a potential peripheral amyloid accumulation, may also result in the derangement of the peripheral nervous system, culminating in detrimental effects on other organs, including the heart. However, whether and how AD pathology modulates cardiac function, neurotrophins, innervation, and amyloidosis is still unknown. Here, we report for the first time that cardiac remodeling, amyloid deposition, and neuro-signaling dysregulation occur in the heart of Tg2576 mice, a widely used model of AD and cerebral amyloidosis.

Methods ad Results

Echocardiographic analysis showed significant deterioration of left ventricle function, evidenced by a decline of both ejection fraction and fraction shortening percentage in 12-month-old Tg2576 mice compared to age-matched WT littermates. Tg2576 mice hearts exhibited an accumulation of amyloid aggregates, including Aβ, an increase in interstitial fibrosis and severe cardiac nervous system dysfunction. The transgenic mice also showed a significant decrease in cardiac nerve fiber density, including both adrenergic and regenerating nerve endings. This myocardial denervation was accompanied by a robust reduction in NGF and BDNF protein expression as well as GAP-43 expression (regenerating fibers) in both the brain and heart of Tg2576 mice. Accordingly, cardiomyocytes and neuronal cells challenged with Aβ oligomers showed significant downregulation of BDNF and GAP-43, indicating a causal effect of Aβ on the loss of cardiac neurotrophic function.

Conclusions

Overall, this study uncovers possible harmful effects of AD on the heart, revealing cardiac degeneration induced by Aβ through fibrosis and neuro-signaling pathway deregulation for the first time in Tg2576 mice. Our data suggest that AD pathology can cause deleterious effects on the heart, and the peripheral neurotrophic pathway may represent a potential therapeutic target to limit these effects.

Soluble and insoluble protein aggregates, endoplasmic reticulum stress, and vascular dysfunction in Alzheimer's disease and cardiovascular diseases

Dementia refers to a particular group of symptoms characterized by difficulties with memory, language, problem-solving, and other thinking skills that affect a person's ability to perform everyday activities. Alzheimer's disease (AD) is the most common form of dementia, affecting about 6.2 million Americans aged 65 years and older. Likewise, cardiovascular diseases (CVDs) are a major cause of disability and premature death, impacting 126.9 million adults in the USA, a number that increases with age. Consequently, CVDs and cardiovascular risk factors are associated with an increased risk of AD and cognitive impairment. They share important age-related cardiometabolic and lifestyle risk factors, that make them among the leading causes of death. Additionally, there are several premises and hypotheses about the mechanisms underlying the association between AD and CVD. Although AD and CVD may be considered deleterious to health, the study of their combination constitutes a clinical challenge, and investigations to understand the mechanistic pathways for the cause-effect and/or shared pathology between these two disease constellations remains an active area of research. AD pathology is propagated by the amyloid β (Aβ) peptides. These peptides give rise to small, toxic, and soluble Aβ oligomers (SPOs) that are nonfibrillar, and it is their levels that show a robust correlation with the extent of cognitive impairment. This review will elucidate the interplay between the effects of accumulating SPOs in AD and CVDs, the resulting ER stress response, and their role in vascular dysfunction. We will also address the potential underlying mechanisms, including the possibility that SPOs are among the causes of vascular injury in CVD associated with cognitive decline. By revealing common mechanistic underpinnings of AD and CVD, we hope that novel experimental therapeutics can be designed to reduce the burden of these devastating diseases. Graphical abstract Alzheimer's disease (AD) pathology leads to the release of Aβ peptides, and their accumulation in the peripheral organs has varying effects on various components of the cardiovascular system including endoplasmic reticulum (ER) stress and vascular damage. Image created with BioRender.com.

Autonomic nervous system and cardiac neuro-signaling pathway modulation in cardiovascular disorders and Alzheimer's disease

The heart is a functional syncytium controlled by a delicate and sophisticated balance ensured by the tight coordination of its several cell subpopulations. Accordingly, cardiomyocytes together with the surrounding microenvironment participate in the heart tissue homeostasis. In the right atrium, the sinoatrial nodal cells regulate the cardiac impulse propagation through cardiomyocytes, thus ensuring the maintenance of the electric network in the heart tissue. Notably, the central nervous system (CNS) modulates the cardiac rhythm through the two limbs of the autonomic nervous system (ANS): the parasympathetic and sympathetic compartments. The autonomic nervous system exerts non-voluntary effects on different peripheral organs. The main neuromodulator of the Sympathetic Nervous System (SNS) is norepinephrine, while the principal neurotransmitter of the Parasympathetic Nervous System (PNS) is acetylcholine. Through these two main neurohormones, the ANS can gradually regulate cardiac, vascular, visceral, and glandular functions by turning on one of its two branches (adrenergic and/or cholinergic), which exert opposite effects on targeted organs. Besides these neuromodulators, the cardiac nervous system is ruled by specific neuropeptides (neurotrophic factors) that help to preserve innervation homeostasis through the myocardial layers (from epicardium to endocardium). Interestingly, the dysregulation of this neuro-signaling pathway may expose the cardiac tissue to severe disorders of different etiology and nature. Specifically, a maladaptive remodeling of the cardiac nervous system may culminate in a progressive loss of neurotrophins, thus leading to severe myocardial denervation, as observed in different cardiometabolic and neurodegenerative diseases (myocardial infarction, heart failure, Alzheimer's disease). This review analyzes the current knowledge on the pathophysiological processes involved in cardiac nervous system impairment from the perspectives of both cardiac disorders and a widely diffused and devastating neurodegenerative disorder, Alzheimer's disease, proposing a relationship between neurodegeneration, loss of neurotrophic factors, and cardiac nervous system impairment. This overview is conducive to a more comprehensive understanding of the process of cardiac neuro-signaling dysfunction, while bringing to light potential therapeutic scenarios to correct or delay the adverse cardiovascular remodeling, thus improving the cardiac prognosis and quality of life in patients with heart or neurodegenerative disorders.

Relationships between cerebral small vessel diseases markers and cognitive performance in stroke-free patients with atrial fibrillation

Background

Atrial fibrillation (AF) is related to an increased risk of cognitive dysfunction. Besides clinically overt stroke, AF can damage the brain via several pathophysiological mechanisms. We aimed to assess the potential mediating role of cerebral small vessel disease (SVD) and cognitive performance in individuals with AF.

Methods

Stroke-free individuals with AF from the cardiological outpatient clinic at West China Hospital of Sichuan University were recruited. Extensive neuropsychological testing tools were assessed including global function, domains of attention, executive functions, learning, and memory. 3 T magnetic resonance imaging (MRI) was used for SVD markers assessment of white matter hyperintensities (WMH), lacunes, cerebral microbleeds (CMBs), and enlarged perivascular spaces (EPVS). The correlation between SVD markers and cognitive measures was analyzed by multivariate linear regression models.

Results

We finally enrolled 158 participants, of whom 95 (60.1%) were males. In multivariate models, the presence of lacunes independently associated with Montreal Cognitive Assessment (Model 1: ß = 0.52, Model 2: ß = 0.55), Rey Auditory Verbal Learning Test-immediate and delayed recall (Model 1: ß = 0.49; ß = 0.69; Model 2: ß = 0.53; ß = 0.73) as well as Stroop-A_correct (Model 1: ß = 0.12; Model 2: ß = 0.13), while total WMH severity independently associated with Stroop_time-A (Model 1: ß = 0.24; Model 3: ß = 0.27), Stroop_time-B (Model 1: ß = 0.17; Model 3: ß = 0.17), Stroop_time-C (Model 1: ß = 0.22; Model 3: ß = 0.21) and Shape Trail Test-A (Model 1: ß = 0.17; Model 3: ß = 0.16).

Conclusion

In our cohort of stroke-free individuals with AF, lacunes, and WMHs were independently associated with cognitive decline while EPVS and CMBs did not show significance. Assessment of SVD MRI markers might be valuable for cognition risk stratification and facilitate optimal management of patients with AF.

Impact of catheter ablation versus medical therapy on cognitive function in atrial fibrillation: a systematic review

PURPOSE

Atrial fibrillation is associated with an increased risk of cognitive impairment. It is unclear whether the restoration of sinus rhythm with catheter ablation may modify this risk. We conducted a systematic review of studies comparing cognitive outcomes following catheter ablation with medical therapy (rate and/or rhythm control) in atrial fibrillation.

METHODS

Searches were performed on the following databases from their inception to 17 October 2021: PubMed, OVID Medline, Embase and Cochrane Library. The inclusion criteria comprised studies comparing catheter ablation against medical therapy (rate and/or rhythm control in conjunction with anticoagulation where appropriate) which included cognitive assessment and/or a diagnosis of dementia as an outcome.

RESULTS

A total of 599 records were screened. Ten studies including 15,886 patients treated with catheter ablation and 42,684 patients treated with medical therapy were included. Studies which compared the impact of catheter ablation versus medical therapy on quantitative assessments of cognitive function yielded conflicting results. In studies, examining new onset dementia during follow-up, catheter ablation was associated with a lower risk of subsequent dementia diagnosis compared to medical therapy (hazard ratio: 0.60 (95% confidence interval 0.42-0.88, p < 0.05)).

CONCLUSION

The accumulating evidence linking atrial fibrillation with cognitive impairment warrants the design of atrial fibrillation treatment strategies aimed at minimising cognitive decline. However, the impact of catheter ablation and atrial fibrillation medical therapy on cognitive decline is currently uncertain. Future studies investigating atrial fibrillation treatment strategies should include cognitive outcomes as important clinical endpoints.

Abnormal circadian blood pressure regulation and cognitive impairment in α-synucleinopathies

Circadian blood pressure (BP) rhythm is important for the maintenance of healthy daily life, and its disruption is associated with poor outcomes. Cardiovascular autonomic failure is often observed in older populations but has a greater impact on neurodegenerative disorders such as α-synucleinopathies. These BP abnormalities include orthostatic hypotension (OH), supine hypertension (SH), and a loss of nocturnal BP fall. OH not only causes falls or syncope but is also related to cognitive impairment in α-synucleinopathies. For example, OH doubles or triples the risk for the development of cognitive impairment in Parkinson's disease (PD). The diffuse central and peripheral neuropathology of α-synuclein may contribute to both OH and cognitive impairment. Moreover, repeated cerebral hypoperfusion in OH is thought to be related to cerebrovascular and neuronal damage, which may cause cognitive impairment. SH, which often coexists with OH, is also associated with cognitive impairment through cerebrovascular damage, such as white matter lesions and cerebral microbleeds. The reverse-dipping (riser) pattern on ambulatory BP monitoring is commonly observed in PD (∼56%), regardless of disease duration and severity. It is also related to cognitive impairment and more pronounced when coexisting with OH. These abnormal circadian BP profiles may be synergistically associated with cognitive impairment and poor outcomes in α-synucleinopathies. Although evidence for aggressive control of BP dysregulation improving cognitive impairment and outcomes is limited, regular BP monitoring appears to be important for total management of α-synucleinopathies.

Alzheimer's disease diagnosis and management: Perspectives from around the world

Alzheimer's disease (AD) and other dementias are a global challenge. Early diagnosis is important to manage the disease. However, there are barriers to diagnosis that differ by region. Researchers from Brazil, China, Nigeria, Spain, and Sweden have identified key barriers to AD diagnosis in their countries. In Brazil, socioeconomic inequalities and poor recognition of dementia by physicians can prevent diagnosis. In China, a very large population and lack of physician training in dementia make diagnosis problematic. In Nigeria, socioeconomic inequalities and cultural stigma can stand in the way of diagnosis. In Spain, patient hesitancy and an overloaded health-care system are barriers to diagnosis. In Sweden, inconsistent use of biomarkers is a prominent barrier to diagnosis of AD. To support diagnosis, more focus is needed on education of patients and physicians, increased use of support services, and improved access to biomarkers to accurately diagnose AD.

Atrial Fibrillation and the Risk of Early‐Onset Dementia: A Systematic Review and Meta‐Analysis

Background

Recent studies have identified an increased risk of dementia in patients with atrial fibrillation (AF). However, both AF and dementia usually manifest late in life. Few studies have investigated this association in adults with early‐onset dementia. The aim of this study was to investigate the relationship between AF and early‐onset dementia.

Methods and Results

We searched the PubMed/MEDLINE, Embase, and Scopus databases through April 15, 2022, for studies reporting on the association between AF and dementia in adults aged <70 years, without language restrictions. Two reviewers independently performed the study selection, assessed the risk of bias, and extracted the study data. We performed a meta‐analysis of early‐onset dementia risk according to occurrence of AF using a random‐effects model. We retrieved and screened 1006 potentially eligible studies. We examined the full text of 33 studies and selected the 6 studies that met our inclusion criteria. The pooled analysis of their results showed an increased risk of developing dementia in individuals with AF, with a summary relative risk of 1.50 (95% CI, 1.00–2.26) in patients aged <70 years, and 1.06 (95% CI, 0.55–2.06) in those aged <65 years.

Conclusions

In this systematic review and meta‐analysis, AF was a risk factor for dementia in adults aged <70 years, with an indication of a slight and statistically imprecise excess risk already at ages <65 years. Further research is needed to assess which characteristics of the arrhythmia and which mechanisms play a role in this relationship.

Environmental and lifestyle risk factors for early-onset dementia: a systematic review

BACKGROUND AND AIM

The term early-onset dementia (EOD) encompasses several forms of neurodegenerative diseases characterized by symptom onset before 65 years and leading to severe impact on subjects already in working activities, as well as on their family and caregivers. Despite the increasing incidence, the etiology is still unknown, with possible association of environmental factors, although the evidence is still scarce. In this review, we aimed to assess how several environmental and lifestyle factors may be associated with the onset of this disease.

METHODS

We conducted a literature search in PubMed and EMBASE databases up to May 6, 2022, to retrieve epidemiological studies evaluating the effect of environmental and lifestyle factors on EOD risk.

RESULTS

We eventually included 22 studies, ten with cohort and twelve with case-control design. Traumatic injury, especially on the head/brain, some cardiovascular diseases such as atrial fibrillation and stroke, metabolic diseases including diabetes and hypercholesterolemia, and alcohol consumption have been identified as potential risk factors for EOD. Conversely, playing leisure activities including sports (without trauma), higher educational attainment and higher adherence to Mediterranean DASH-Intervention for Neurodegenerative Delay (MIND) diet appeared to be protective for EOD.

CONCLUSIONS

The literature on environmental risk factors for EOD has been considerably growing in recent years. Overall, it supports an association between some environmental and lifestyle factors with disease risk. However, additional high-quality research is required to confirm these relations and its causal nature (www.actabiomedica.it).

Pathophysiological pathways in patients with heart failure and atrial fibrillation

Aims

Atrial fibrillation (AF) and heart failure (HF) are two growing epidemics that frequently co-exist. We aimed to gain insights into the underlying pathophysiological pathways in HF patients with AF by comparing circulating biomarkers using pathway overrepresentation analyses.

Methods and results

From a panel of 92 biomarkers from different pathophysiological domains available in 1620 patients with HF, we first tested which biomarkers were dysregulated in patients with HF and AF (n = 648) compared with patients in sinus rhythm (n = 972). Secondly, pathway overrepresentation analyses were performed to identify biological pathways linked to higher plasma concentrations of biomarkers in patients who had HF and AF. Findings were validated in an independent HF cohort (n = 1219, 38% with AF). Patient with AF and HF were older, less often women, and less often had a history of coronary artery disease compared with those in sinus rhythm. In the index cohort, 24 biomarkers were up-regulated in patients with AF and HF. In the validation cohort, eight biomarkers were up-regulated, which all overlapped with the 24 biomarkers found in the index cohort. The strongest up-regulated biomarkers in patients with AF were spondin-1 (fold change 1.18, P = 1.33 × 10⁻¹²), insulin-like growth factor-binding protein-1 (fold change 1.32, P = 1.08 × 10⁻⁸), and insulin-like growth factor-binding protein-7 (fold change 1.33, P = 1.35 × 10⁻¹⁸). Pathway overrepresentation analyses revealed that the presence of AF was associated with activation amyloid-beta metabolic processes, amyloid-beta formation, and amyloid precursor protein catabolic processes with a remarkable consistency observed in the validation cohort.

Conclusion

In two independent cohorts of patients with HF, the presence of AF was associated with activation of three pathways related to amyloid-beta. These hypothesis-generating results warrant confirmation in future studies.

Risk of dementia in patients with atrial fibrillation: Short versus long follow-up. A systematic review and meta-analysis

BACKGROUND

No previous meta-analyses have compared the risk of dementia, due to an underlying atrial fibrillation (AF), in the short-term versus the long-term period.

AIM

To perform an update meta-analysis of studies examining the association between AF and dementia and the relative impact of follow-up period.

METHODS

Data were obtained searching MEDLINE and Scopus for all investigations published between 1 January 2000 and March 1, 2021 reporting the risk of dementia in AF patients. The following MeSH terms were used for the search: "Atrial Fibrillation" AND "Dementia" OR "Alzheimer's disease". From each study, the adjusted hazard ratio (aHR) with the related 95% confidence interval (CI) was pooled using a random effect model.

RESULTS

The analysis was carried out on 18 studies involving 3.559.349 subjects, of which 902.741 (25.3%) developed dementia during follow-up. A random effect model revealed an aHR of 1.40 (95% CI: 1.27-1.54, p < 0.0001; I2  = 93.5%) for dementia in subjects with AF. Stratifying the studies according to follow-up duration, those having a follow-up ≥10 years showed an aHR for dementia of 1.37 (95% CI: 1.21-1.55, p < 0.0001, I2  = 96.6%), while those with a follow-up duration <10 years has a slightly higher aHR for dementia (HR: 1.59, 95%CI: 1.51-1.67, p < 0.0001, I2  = 49%). Nine studies showed that the aHR for Alzheimer's disease (AD) in AF patients was 1.30 (95%CI: 1.12-1.51, p < 0.0001, I2  = 87.6%).

CONCLUSIONS

Evidence suggests that patients with AF have an increased risk of developing dementia and AD. The risk of dementia was slightly higher when the follow-up was shorter than 10 years.

Mendelian randomization study on atrial fibrillation and cardiovascular disease subtypes

Atrial fibrillation (AF) has been associated with numerous diseases. However, whether AF is a cause or consequence of these diseases is uncertain. To clarify, we assessed the causal role of AF on ischemic heart disease (IHD), stroke, other cardiovascular disease (CVD) subtypes, type 2 diabetes mellitus (T2DM), and late-onset AD using bi-directional two-sample Mendelian randomization (MR) among people primarily of European descent. Genetically predicted log odds of AF was associated with any stroke (odds ratio (OR) 1.22, 95% CI 1.18 to 1.27), particularly cardioembolic stroke and possibly subdural hemorrhage, with sensitivity analyses showing similar positive findings. Genetically predicted AF was also associated with arterial thromboembolism (1.32, 1.13 to 1.53), and heart failure (1.26, 1.21 to 1.30). No association of genetically predicted AF with IHD, T2DM, cognitive function, or late-onset AD was found. Conversely, genetically predicted IHD, heart failure and possibly ischemic stroke, particularly cardioembolic stroke, were positively associated with AF. Atrial fibrillation plays a role in any stroke, arterial thromboembolism, and heart failure, corroborating current clinical guidelines on the importance of preventing these complications by effective AF management. In addition, patients with IHD, heart failure or possibly ischemic stroke might be predisposed to developing AF, with implications for management.

Haemodynamic impairment along the Alzheimer's disease continuum

BACKGROUND AND PURPOSE

Alzheimer's disease (AD) is considered a clinical and biological continuum identified via cerebrospinal fluid (CSF) or imaging biomarkers. Chronic hypoperfusion is held as one of the main features of Alzheimer's disease, as part of the processes causing neuronal degeneration. The mechanism responsible for such condition is still debated, although recently a direct connection with amyloid peptides has been shown. Here the aim was to investigate whether measures of hypoperfusion change along the AD continuum.

METHODS

Seventy patients with mild AD were recruited and stratified according to their CSF biomarker profile-as indicated by the National Institute on Aging and Alzheimer's Association research framework-into patients with either isolated amyloid pathology (A+T-) or full-blown AD (A+T+), and further layered according to apolipoprotein E genotype. After evaluation of vascular risk factors, a transcranial Doppler was performed on each patient, to evaluate mean flow velocity and pulsatility index in the middle cerebral artery, and to calculate the breath-holding index. Patients were compared to a cohort of 17 healthy controls.

RESULTS

The breath-holding index was reduced in the AD continuum and was inversely correlated to CSF amyloid β42 levels. Such correlation was stronger in the A+T+ than in the A+T- group, and unexpectedly reached statistical significance only in the E3 and not in the E4 genotype carriers.

CONCLUSIONS

These results suggest a tight and effective relationship between amyloid β42, vascular hypoperfusion, cerebrovascular reactivity and epsilon genotype.

The Microbiota-Gut-Brain Axis and Alzheimer's Disease: Neuroinflammation Is to Blame?

For years, it has been reported that Alzheimer’s disease (AD) is the most common cause of dementia. Various external and internal factors may contribute to the early onset of AD. This review highlights a contribution of the disturbances in the microbiota–gut–brain (MGB) axis to the development of AD. Alteration in the gut microbiota composition is determined by increase in the permeability of the gut barrier and immune cell activation, leading to impairment in the blood–brain barrier function that promotes neuroinflammation, neuronal loss, neural injury, and ultimately AD. Numerous studies have shown that the gut microbiota plays a crucial role in brain function and changes in the behavior of individuals and the formation of bacterial amyloids. Lipopolysaccharides and bacterial amyloids synthesized by the gut microbiota can trigger the immune cells residing in the brain and can activate the immune response leading to neuroinflammation. Growing experimental and clinical data indicate the prominent role of gut dysbiosis and microbiota–host interactions in AD. Modulation of the gut microbiota with antibiotics or probiotic supplementation may create new preventive and therapeutic options in AD. Accumulating evidences affirm that research on MGB involvement in AD is necessary for new treatment targets and therapies for AD.

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

The interplay between host genetics and the gut microbiome reveals common and distinct microbiome features for complex human diseases

BACKGROUND

Interest in the interplay between host genetics and the gut microbiome in complex human diseases is increasing, with prior evidence mainly being derived from animal models. In addition, the shared and distinct microbiome features among complex human diseases remain largely unclear.

RESULTS

This analysis was based on a Chinese population with 1475 participants. We estimated the SNP-based heritability, which suggested that Desulfovibrionaceae and Odoribacter had significant heritability estimates (0.456 and 0.476, respectively). We performed a microbiome genome-wide association study to identify host genetic variants associated with the gut microbiome. We then conducted bidirectional Mendelian randomization analyses to examine the potential causal associations between the gut microbiome and complex human diseases. We found that Saccharibacteria could potentially decrease the concentration of serum creatinine and increase the estimated glomerular filtration rate. On the other hand, atrial fibrillation, chronic kidney disease and prostate cancer, as predicted by host genetics, had potential causal effects on the abundance of some specific gut microbiota. For example, atrial fibrillation increased the abundance of Burkholderiales and Alcaligenaceae and decreased the abundance of Lachnobacterium, Bacteroides coprophilus, Barnesiellaceae, an undefined genus in the family Veillonellaceae and Mitsuokella. Further disease-microbiome feature analysis suggested that systemic lupus erythematosus and chronic myeloid leukaemia shared common gut microbiome features.

CONCLUSIONS

These results suggest that different complex human diseases share common and distinct gut microbiome features, which may help reshape our understanding of disease aetiology in humans. Video Abstract.

Repositioning medication for cardiovascular and cerebrovascular disease to delay the onset and prevent progression of Alzheimer's disease

Alzheimer's disease (AD) is a complex, progressive, neurodegenerative disorder. As with other common chronic diseases, multiple risk factors contribute to the onset and progression of AD. Many researchers have evaluated the epidemiologic and pathophysiological association between AD, cardiovascular diseases (CVDs), and cerebrovascular diseases (CBVDs), including commonly reported risk factors such as diabetes, hypertension, and dyslipidemia. Relevant therapies of CVDs/CBVDs for the attenuation of AD have also been empirically investigated. Considering the challenges of new drug development, in terms of cost and time, multifactorial approaches such as therapeutic repositioning of CVD/CBVD medication should be explored to delay the onset and progression of AD. Thus, in this review, we discuss our current understanding of the association between cardiovascular risk factors and AD, as revealed by clinical and non-clinical studies, as well as the therapeutic implications of CVD/CBVD medication that may attenuate AD. Furthermore, we discuss future directions by evaluating ongoing trials in the field.

Peri-procedural novel oral anticoagulants dosing strategy during atrial fibrillation ablation: A meta-analysis

BACKGROUND

This study aimed at determining whether uninterrupted novel oral anticoagulant (UI-NOAC) would have similar rates of bleeding and thromboembolic events as minimally interrupted NOAC (MI-NOAC) at the time of ablation for atrial fibrillation (AF) as relevant studies are scarce.

METHODS

We searched through the PubMed, EMBASE, and Cochrane Library databases for prospective observational studies (POSs) or randomised controlled trials (RCTs) comparing UI-NOAC versus MI-NOAC from their establishment to January 2020. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to compare the pooled treatment effect.

RESULTS

Nine studies (three POSs and six RCTs) with 2578 patients were included in the final analysis (55% patients received MI-NOAC). No significant difference was found regarding the risk of major bleeding (OR 0.92, 95% CI 0.43-2.00, P = .84, I²   = 0%). Both groups were comparable in all subgroups ([Asians: OR 1.00, 95% CI 0.43-2.36, P = .99, I²   = 0%], [non-Asians: OR 0.64, 95% CI 0.11-3.88, P = .63, I²   = 0%], [RCTs: OR 0.85, 95% CI 0.37-1.97, P = .71, I²   = 0%], and [POSs: OR 0.52, 95% CI 0.19-12.01, P = .69, I²   = 0%]). The risk of minor bleeding (P = .88) or stroke (P = .69) was comparable between the groups. UI-NOAC resulted in a significant reduction in silent stroke (SS) (OR 0.44, 95% CI 0.23-0.83, P = .01, I²   = 72%). No significant difference was found in SS between once-daily and twice-daily NOACs (OR 0.91, 95% CI 0.63-1.33, P = .64, I²   = 0%) in the MI-NOAC group.

CONCLUSIONS

UI-NOAC, as a peri-procedural anticoagulation strategy for catheter ablation in AF, had similar safety compared with MI-NOAC, but was advantageous in terms of SS.

Increased Levels of Coagulation Factor XI in Plasma Are Related to Alzheimer's Disease Diagnosis

BACKGROUND

Alzheimer's disease is a complex disorder of unclear etiology that develops in the elderly population. It is a debilitating, progressive neurodegeneration for which disease-modifying therapies do not exist. Previous studies have suggested that, for a subset of patients, dysregulation in hemostasis might be one of the molecular mechanisms that ultimately leads to the development of neurodegeneration resulting in cognitive decline that represents the most prominent symptomatic characteristic of Alzheimer's disease.

OBJECTIVE

To examine a relationship between factors that are part of coagulation and anticoagulation pathways with cognitive decline that develops during Alzheimer's disease.

METHODS

SOMAscan assay was used to measure levels of coagulation/anticoagulation factors V, VII, IX, X, Xa, XI, antithrombin III, protein S, protein C, and activated protein C in plasma samples obtained from three groups of subjects: 1) subjects with stable cognitively healthy function, 2) subjects with stable mild cognitive impairment, and 3) subjects diagnosed with probable Alzheimer's disease.

RESULTS

Our results show that protein levels of coagulation factor XI are significantly increased in patients who are diagnosed with probable Alzheimer's disease compared with cognitively healthy subjects or patients diagnosed with mild cognitive impairment. Furthermore, our results demonstrate that significant predictors of Alzheimer's-type diagnosis are factors IX and XI-an increase in both factors is associated with a reduction in cognitive function.

CONCLUSION

Our study justifies further investigations of biological pathways involving coagulation/anticoagulation factors in relation to dementia, including dementia resulting from Alzheimer's-type neurodegeneration.

The environmental toxicant ziram enhances neurotransmitter release and increases neuronal excitability via the EAG family of potassium channels

Environmental toxicants have the potential to contribute to the pathophysiology of multiple complex diseases, but the underlying mechanisms remain obscure. One such toxicant is the widely used fungicide ziram, a dithiocarbamate known to have neurotoxic effects and to increase the risk of Parkinson's disease. We have used Drosophila melanogaster as an unbiased discovery tool to identify novel molecular pathways by which ziram may disrupt neuronal function. Consistent with previous results in mammalian cells, we find that ziram increases the probability of synaptic vesicle release by dysregulation of the ubiquitin signaling system. In addition, we find that ziram increases neuronal excitability. Using a combination of live imaging and electrophysiology, we find that ziram increases excitability in both aminergic and glutamatergic neurons. This increased excitability is phenocopied and occluded by null mutant animals of the ether a-go-go (eag) potassium channel. A pharmacological inhibitor of the temperature sensitive hERG (human ether-a-go-go related gene) phenocopies the excitability effects of ziram but only at elevated temperatures. seizure (sei), a fly ortholog of hERG, is thus another candidate target of ziram. Taken together, the eag family of potassium channels emerges as a candidate for mediating some of the toxic effects of ziram. We propose that ziram may contribute to the risk of complex human diseases by blockade of human eag and sei orthologs, such as hERG.

Impaired cerebral autoregulation is associated with poststroke cognitive impairment

Objective

To investigate whether dynamic cerebral autoregulation (CA) and neuroimaging characteristics are determinants of poststroke cognitive impairment (PSCI).

Methods

Eighty patients within 7 days of acute ischemic stroke and 35 age‐ and sex‐matched controls were enrolled. In the patients with stroke, brain magnetic resonance imaging and dynamic CA were obtained at baseline, and dynamic CA was followed up at 3 months and 1 year. Montreal Cognitive Assessment (MoCA) was performed at 3 months and 1 year. Patients with a MoCA score <23 at 1 year were defined as having PSCI, and those with a MoCA score that decreased by 2 points or more between the 3‐month and 1‐year assessments were defined as having progressive cognitive decline.

Results

In total, 65 patients completed the study and 16 developed PSCI. The patients with PSCI exhibited poorer results for all cognitive domains than did those without PSCI. The patients with PSCI also had poorer CA (lower phase shift between cerebral blood flow and blood pressure waveforms in the very low frequency band) compared with that of the patients without PSCI and controls at baseline and 1 year. CA was not different between the patients without PSCI and controls. In the multivariate analysis, low education level, lobar microbleeds, and impaired CA (very low frequency phase shift [≤46°] within 7 days of stroke), were independently associated with PSCI. In addition, impaired CA was associated with progressive cognitive decline.

Interpretation

Low education level, lobar microbleeds, and impaired CA are involved in the pathogenesis of PSCI.

Prevalence of Comorbidities in Individuals Diagnosed and Undiagnosed with Alzheimer's Disease in León, Spain and a Proposal for Contingency Procedures to Follow in the Case of Emergencies Involving People with Alzheimer's Disease

Background: Alzheimer's disease (AD) which is the most common type of dementia is characterized by mental or cognitive disorders. People suffering with this condition find it inherently difficult to communicate and describe symptoms. As a consequence, both detection and treatment of comorbidities associated with Alzheimer's disease are substantially impaired. Equally, action protocols in the case of emergencies must be clearly formulated and stated. Methods: We performed a bibliography search followed by an observational and cross-sectional study involving a thorough review of medical records. A group of AD patients was compared with a control group. Each group consisted of 100 people and were all León residents aged ≥65 years. Results: The following comorbidities were found to be associated with AD: cataracts, urinary incontinence, osteoarthritis, hearing loss, osteoporosis, and personality disorders. The most frequent comorbidities in the control group were the following: eye strain, stroke, vertigo, as well as circulatory and respiratory disorders. Comorbidities with a similar incidence in both groups included type 2 diabetes mellitus, glaucoma, depression, obesity, arthritis, and anxiety. We also reviewed emergency procedures employed in the case of an emergency involving an AD patient. Conclusions: Some comorbidities were present in both the AD and control groups, while others were found in the AD group and not in the control group, and vice versa.

Inflammatory and Infectious Processes Serve as Links between Atrial Fibrillation and Alzheimer's Disease

Atrial fibrillation (AF) is one of the most prevalent forms of arrhythmia that carries an increased risk of stroke which, in turn, is strongly associated with cognitive decline. The majority of dementia cases are caused by Alzheimer's disease (AD) with obscure pathogenesis. While the exact mechanisms are unknown, the role of inflammatory processes and infectious agents have recently been implicated in both AD and AF, suggesting a common link between these maladies. Here, we present the main shared pathways underlying arrhythmia and memory loss. The overlapping predictive biomarkers and emerging joint pharmacological approaches are also discussed.

Cognitive Screening in Geriatric Patients with Atrial Fibrillation Evaluated for Falls

Background

Atrial fibrillation (AF) is associated with cognitive decline and dementia. This study investigates whether the Montreal Cognitive Assessment (MoCA) detects more cognitive decline than the Mini Mental State Examination (MMSE) in patients with AF. Secondary aims were to assess the rate of white matter hyperintensities (WMH) and mesotemporal atrophy (MTA) in patients with AF.

Methods

Observational cohort study. Patients of 65 years and older that visited the Fall and Syncope Clinic were eligible. Patients were included if both a MoCA and MMSE were completed. In patients of whom an MRI was performed WMH were assessed with the Fazekas score and MTA was assessed with the MTA score. To assess frailty a Frailty Index (FI) was calculated.

Results

428 patients were included. Mean age was 80 years, 66% was female. The mean FI was 0.28 (CI 0.11 to 0.45), indicative of severe frailty. In 90 patients AF was known and in 9 patients it was first diagnosed, overall prevalence 23%. Cognitive impairment was found with the MoCA in 80% of patients with persistent AF, versus in 33% with the MMSE. Patients with paroxysmal AF had more WMH than patients with SR (p 0.04). No differences were found in relevant MTA between patients with AF or SR.

Conclusions

Cognitive decline in patients with AF is better detected using the MoCA than the MMSE. This means that in daily clinical practice, the MOCA should be used instead of the MMSE for patients with AF.

Atrial Fibrillation and Cognitive Impairment: An Associated Burden or Burden by Association?

Growing evidence suggests that atrial fibrillation (AF), in addition to its thromboembolic risk, is a risk factor for cognitive impairment (CI) via several pathways and mechanisms, further contributing to morbidity/mortality. Prior stroke is a contributor to CI, but AF is also associated with CI independently from prior stroke. Silent brain infarctions, microemboli and microbleeds, brain atrophy, cerebral hypoperfusion from widely fluctuating ventricular rates, altered hemostatic function, vascular oxidative stress, and inflammation may all exacerbate CI, particularly in patients with persistent/permanent rather than paroxysmal AF and with increased duration/burden of the arrhythmia. Brain magnetic resonance imaging is an important screening tool in eliciting and monitoring vascular and nonvascular lesions contributing to CI. Evidence is also emerging about the role of genetics in CI development. Anticoagulation and rhythm/rate control strategies may protect against CI preventing or slowing its progression or conversion to dementia, particularly at the early stages when CI may still be a treatable condition. Importantly, AF and CI share many common risk factors. Thus, screening for these 2 conditions and searching for and managing modifiable risk factors and potentially reversible causes for both AF and CI remains an important step toward prevention or amelioration of the impact incurred by these 2 conditions.

Opportunistic screening for atrial fibrillation with a single lead device in geriatric patients

OBJECTIVE

To determine the diagnostic yield of repeated screening for atrial fibrillation (AF) among geriatric patients.

METHODS

A pragmatic prospective cohort study into applying opportunistic screening for AF with a handheld single lead ECG device (SLD) in a geriatric cohort. Consecutive patients of 65 years old and older visiting the geriatric outpatient clinic were eligible for inclusion. A 12 lead ECG was performed, followed by measurements with the SLD during every visit to the geriatric outpatient clinic. A frailty index was based on the accumulation of deficits model.

RESULTS

478 patients were eligible. Patients were excluded if they did not give informed consent (17 patients), had a pacemaker or implantable cardioverter defibrillator (20 patients), or had incomplete medical files (two patients). After exclusion, 439 patients participated in this study. The mean age was 78 years (range 65 to 100 years), 54% were female. AF was known in 89 patients (20%), first detected on the baseline ECG in four patients (1%) and first detected with the SLD in 20 patients (5%) during follow up visits. Sensitivity of the SLD was 90.0%, specificity 99.0%, negative predictive value 99.7%, and positive predictive value 73.5%. Most patients (82%) with AF were frail and 53% were severely frail.

CONCLUSION

Repeated screening in geriatric patients has a five times higher diagnostic yield than usual care. It was easily combined with usual care. Because of the positive predictive value of 73.5%, it remains necessary to confirm AF with a 12 lead ECG or 24-h Holter monitoring.

Evaluating the functional and structural changes in the vagus nerve: Should the vagus nerve be tested in patients with atrial fibrillation?

One of the multiple factors believed to contribute to the initiation and maintenance of atrial fibrillation (AF) is altered activity of the autonomic nervous system. Debate continues about the role of the vagus nerve (CNX) in AF since its effect depends on the level of its activation as well as on simultaneous sympathetic activation. Surplus either vagal or sympathetic activity may rarely induce the development of AF; however, typically loss of balance between the both systems mediates the induction and maintenance of AF. Vagal stimulation has been proposed as a novel treatment approach for AF because the anti-arrhythmic effects of low-level vagus nerve stimulation have been shown both in patients and animal models. We hypothesize that in typical cases of AF without any clear trigger by either autonomic nervous system, significant changes in vagus somatosensory evoked potentials and a smaller cross-sectional area of CNX could be detected, representing functional and structural changes in CNX, respectively.

The association between atrial fibrillation and Alzheimer's disease: fact or fallacy? A systematic review and meta-analysis

BACKGROUND

The association between atrial fibrillation and dementia has been described. Whether a specific association exists between atrial fibrillation and Alzheimer's disease remains uncertain. This study aims to assess the association between atrial fibrillation and Alzheimer's disease through a systematic review and meta-analysis of the literature.

METHODS

An exhaustive search of electronic databases up to October 2018 was conducted. Studies that identified patients with and without atrial fibrillation as well as patients with and without Alzheimer's disease and reported results of at least one relevant outcome, including hazard ratio of the association between atrial fibrillation and Alzheimer's disease were included in this analysis. The hazard ratios and their confidence interval were then pooled using a DerSimonian and Laird random effects model.

RESULTS

Six studies enrolling a total of 56 370 patients were included. At baseline, the mean or median ages ranged from 50 to 78 years with a subsequent follow-up of 3 to 25 years. The random-effect pooled analysis showed a hazard ratio of 1.30 (95% confidence interval 1.01-1.59) and the heterogeneity was not significant, I 48.1%. All of the included studies were rated as good quality.

CONCLUSION

Pooled analysis suggest that patients with atrial fibrillation may be exposed to an increased risk of developing new onset of Alzheimer's disease. Given the relevant clinical implications, further studies are required to corroborate these findings.

Oral anticoagulant and reduced risk of dementia in patients with atrial fibrillation: A population-based cohort study

BACKGROUND

Whether oral anticoagulation (OAC) can prevent dementia or cognitive impairment (CI) in patients with atrial fibrillation (AF) remains unclear.

OBJECTIVE

The purpose of this study was to investigate the risk of dementia/CI among AF patients with and without OAC treatment.

METHODS

We conducted a retrospective cohort study using United Kingdom (UK) primary care data (2000-2017). Participants with newly diagnosed AF without a history of dementia/CI were identified. Inverse probability of treatment weights based on propensity scores and Cox regression were used to compare the dementia outcomes.

RESULTS

Among 84,521 patients with AF, 35,245 were receiving OAC treatment and 49,276 received no OAC treatment; of these patients, 29,282 were receiving antiplatelets. Over a mean follow-up of 5.9 years, 5295 patients developed dementia/CI. OAC treatment was associated with a lower risk of dementia/CI compared to no OAC treatment (hazard ratio [HR] 0.90; 95% confidence interval 0.85-0.95; P <.001) or antiplatelets (HR 0.84; 95% confidence interval 0.79-0.90; P <.001). No significant difference in dementia risk was observed for direct oral anticoagulants (DOACs) vs warfarin (HR 0.89; 95% confidence interval 0.70-1.14; P = .373), whereas dual therapy (OAC plus an antiplatelet agent) was associated with a higher risk of dementia/CI compared with no treatment (HR 1.17; 95% confidence interval 1.05-1.31; P = .006).

CONCLUSION

OAC use was associated with a lower risk of dementia/CI compared to non-OAC and antiplatelet treatment among AF patients. The evidence for DOAC on cognitive function is insufficient, and further studies including randomized clinical trials are warranted.

Cognitive Impairment Before Atrial Fibrillation-Related Ischemic Events: Neuroimaging and Prognostic Associations

Background

It is likely that a proportion of poststroke cognitive impairment is sometimes attributable to unidentified prestroke decline; prestroke cognitive function is also clinically relevant because it is associated with poor functional outcomes, including death. We investigated the radiological and prognostic associations of preexisting cognitive impairment in patients with ischemic stroke or transient ischemic attack associated with atrial fibrillation.

Methods and Results

We included 1102 patients from the prospective multicenter observational CROMIS‐2 (Clinical Relevance of Microbleeds in Stroke 2) atrial fibrillation study. Preexisting cognitive impairment was identified using the 16‐item Informant Questionnaire for Cognitive Decline in the Elderly. Functional outcome was measured using the modified Rankin scale. Preexisting cognitive impairment was common (n=271; 24.6%). The presence of lacunes (odds ratio [OR], 1.50; 95% CI, 1.03–1.05; P=0.034), increasing periventricular white matter hyperintensity grade (per grade increase, OR, 1.38; 95% CI, 1.17–1.63; P<0.0001), deep white matter hyperintensity grade (per grade increase, OR, 1.26; 95% CI, 1.05–1.51; P=0.011), and medial temporal atrophy grade (per grade increase, OR, 1.61; 95% CI, 1.34–1.95; P<0.0001) were independently associated with preexisting cognitive impairment. Preexisting cognitive impairment was associated with poorer functional outcome at 24 months (mRS >2; adjusted OR, 2.43; 95% CI, 1.42–4.20; P=0.001).

Conclusions

Preexisting cognitive impairment in patients with atrial fibrillation–associated ischemic stroke or transient ischemic attack is common, and associated with imaging markers of cerebral small vessel disease and neurodegeneration, as well as with longer‐term functional outcome.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02513316.

Association Between Atrial Fibrillation and Dementia: A Meta-Analysis

Background: A potential evidence from previous epidemiological studies remains conflicting findings regarding the association between atrial fibrillation (AF) and dementia risk. We, therefore, carried out a meta-analysis of relevant studies to investigate the magnitude of the association between AF and dementia risk.

Methods: We performed a systematic literature search of PubMed, EMBASE, and Google Scholar for potential studies between January 1, 1990, and December 31, 2018, with no restriction on the publication language. All potential studies were independently assessed by two reviewers. We only included observational studies that calculated the odds ratio (OR)/hazards ratio (HR) for dementia associated with atrial fibrillation. We first assessed the heterogeneity among study-specific HRs using the Q statistic and I² statistic. We then used the random-effects model to obtain the overall HR and its 95% CI for all studies. We also tested and corrected for publication bias by funnel plot–based methods. The quality of each study was assessed with the Newcastle Ottawa Scale.

Results: A total of 16 studies with 2,415,356 individuals, and approximately 200,653 cases of incidence dementia were included in this study. Patients with AF had a greater risk of incidence dementia than those without AF (random-effect hazard ratio HR: 1.36, 95% CI: 1.23–1.51, p < 0.0001; I² = 83.58). Funnel plot and Egger test did not reveal significant publication bias. However, limitations of the study included high heterogeneity and varying degrees of confounder adjustment across individual studies.

Conclusion: This study serves as added evidence supporting the hypothesis that AF is associated with an increased risk of dementia. More studies are needed to establish whether optimal treatment of AF can reduce or mitigate the risk of dementia.