Atrial fibrillation and cognitive disorders in older people

The use of nonlinear analysis in understanding postural control: A scoping review

Nonlinear analyses have emerged as an approach to unraveling the intricate dynamics and underlying mechanisms of postural control, offering insights into the complex interplay of physiological and biomechanical factors. However, achieving a comprehensive understanding of the application of nonlinear analysis in postural control studies remains a challenge due to the various nonlinear measurement methods currently available. Thus, this scoping review aimed to identify existing nonlinear analyses used to study postural control in both dynamic and quiet tasks, and to summarize and disseminate the available literature on the use of nonlinear analysis in postural control. For this purpose, a scoping review was conducted and reported following the PRISMA Extension for Scoping Reviews (PRISMA-ScR) Checklist and Explanation. Searches were conducted up to July 2023 on PubMed/Medline, Embase, CINAHL, Web of Science, and Google Scholar databases, resulting in the inclusion of 397 unique studies. The main classes employed among the studies were entropy-based, fractal-based, quantification of recurrence plots, and quantification of stability, with a total of 91 different algorithms distributed among these classes. The most common condition used to study postural control was quiet standing, followed by dynamic standing and gait tasks. Although various algorithms were utilized for this purpose, sample entropy was employed in 43% of studies to explore mechanisms related to postural control. Among them, 28% were in quiet standing, 3.27% were in dynamic standing, and 4.78% to study postural control during the gait. The results also provide insights into nonlinear analysis for future studies, concerning the complexity and interactions within the postural control system across various task demands.

Time-varying information measures: an adaptive estimation of information storage with application to brain-heart interactions

Network Physiology is a rapidly growing field of study that aims to understand how physiological systems interact to maintain health. Within the information theory framework the information storage (IS) allows to measure the regularity and predictability of a dynamic process under stationarity assumption. However, this assumption does not allow to track over time the transient pathways occurring in the dynamical activity of a physiological system. To address this limitation, we propose a time-varying approach based on the recursive least squares algorithm (RLS) for estimating IS at each time instant, in non-stationary conditions. We tested this approach in simulated time-varying dynamics and in the analysis of electroencephalographic (EEG) signals recorded from healthy volunteers and timed with the heartbeat to investigate brain-heart interactions. In simulations, we show that the proposed approach allows to track both abrupt and slow changes in the information stored in a physiological system. These changes are reflected in its evolution and variability over time. The analysis of brain-heart interactions reveals marked differences across the cardiac cycle phases of the variability of the time-varying IS. On the other hand, the average IS values exhibit a weak modulation over parieto-occiptal areas of the scalp. Our study highlights the importance of developing more advanced methods for measuring IS that account for non-stationarity in physiological systems. The proposed time-varying approach based on RLS represents a useful tool for identifying spatio-temporal dynamics within the neurocardiac system and can contribute to the understanding of brain-heart interactions.

Economic Burden of Dementia Caused by Cardiovascular Disease in Australia

Background: The established link between cardiovascular disease (CVD) and dementia may provide new insights into dementia prevention. Objective: It aims to quantify the burden of dementia attributable to people with CVD. Methods: A Markov microsimulation model was developed to simulate the lifetime cost and quality-adjusted life-years (QALYs) related to people with and without CVD in Australia. A de-novo systematic review was undertaken to identify all evidence around the association between CVD [i.e., stroke, myocardial infarction (MI), atrial fibrillation (AF), and heart failure (HF)] and the risk of developing dementia. Incremental costs and QALY losses were estimated for people by type of CVD compared to the general Australian population without CVD. Results: Of the comprehensive literature search, 19 observational studies were included in the qualitative synthesis. Patients who had CVD incurred both higher healthcare costs over their lifetime (ranging from $73,131 for patients with AF to $127,396 for patients with HF) and fewer QALYs gains (from –1.099 for patients with MI to –5.163 for patients with stroke), compared to people who did not have CVD. The total incremental economic burden of dementia from patients aged 65 years and over with CVD was $6.45 billion (stroke), $11.89 billion (AF), $17.57 billion (MI), or $7.95 billion (HF) over their remaining life expectancy. Conclusion: The results highlighted the importance of CVD prevention to reduce the CVD burden and decrease the prevalence of dementia. Interventions that target patients with dementia risk factors like CVD may prove to be effective and cost-effective strategies.

[Efficiency of the Decision-Making Module in the Personalized Choice of an Anticoagulant]

Aim        To evaluate the effectiveness of the decision-making module in selecting an oral anticoagulant for patients with atrial fibrillation.Material and methods        638 patients with atrial fibrillation aged 68.2±4.5 years were evaluated. The CHA2DS2-VASc, HAS-BLED, and 2MАСЕ scales, the creatinine clearance calculator, and the Morisky-Green questionnaire were used.Results   311 (48.75 %) patients had paroxysmal atrial fibrillation, 138 (21.6%) had persistent atrial fibrillation, 44 (22.7%) had long-standing persistent atrial fibrillation, and 145 (22.7 %) had permanent atrial fibrillation. Mean CHADS2‑VASc scale score was 4.82; НAS-BLED scale score was 2.9; 2MACE score was 2.28; and compliance score was 3.52. 172 (26.9 %) patients were treated with rivaroxaban; 166 (26 %), with apixaban; 84 (13.2 %), with dabigatran; 210 (32.9 %), with warfarin; and 6 (1 %), with acetylsalicylic acid.Conclusion            The developed decision-making module is based on scientific justification of personalized selection of the oral anticoagulant and updates the knowledge on major issues of prescription.

Hemodynamic Instability in Heart Failure Intensifies Age-Dependent Cognitive Decline

This review attempts to examine two key elements in the evolution of cognitive impairment in the elderly who develop heart failure. First, major left side heart parts can structurally and functionally deteriorate from aging wear and tear to provoke hemodynamic instability where heart failure worsens or is initiated; second, heart failure is a major inducer of cognitive impairment and Alzheimer's disease in the elderly. In heart failure, when the left ventricular myocardium of an elderly person does not properly contract, it cannot pump out adequate blood to the brain, raising the risk of cognitive impairment due to the intensification of chronic brain hypoperfusion. Chronic brain hypoperfusion originates from chronically reduced cardiac output which progresses as heart failure worsens. Other left ventricular heart parts, including atrium, valves, myocardium, and aorta can contribute to the physiological shortfall of cardiac output. It follows that hemodynamic instability and perfusion changes occurring from the aging heart's blood pumping deficiency will, in time, damage vulnerable brain cells linked to specific cognitive regulatory sites, diminishing neuronal energy metabolism to a level where progressive cognitive impairment is the outcome. Could cognitive impairment progress be reversed with a heart transplant? Evidence is presented detailing the errant hemodynamic pathways leading to cognitive impairment during aging as an offshoot of inefficient structural and functional heart parts and their contribution to heart failure.

Dementia and Atrial Fibrillation: Pathophysiological Mechanisms and Therapeutic Implications

Atrial fibrillation increases the risk of stroke by a factor of four- to fivefold, and dementia is a common consequence of stroke. However, atrial fibrillation has been associated with cognitive impairment and dementia, even in patients without prior overt stroke. Nonischemic mechanisms include cerebral hypoperfusion, vascular inflammation, brain atrophy, genetic factors, and shared risk factors such as age or hypertension. Critical appraisal of studies evaluating the association between atrial fibrillation and dementia in stroke-free patients reveals that several suffer from methodological issues, such as not including silent stroke or anticoagulation therapy in multivariate analyses. Some studies show a close relationship between atrial fibrillation and dementia due to silent stroke, in the absence of overt stroke. Evidence is accumulating that anticoagulation may be effective to decrease the risk of dementia in atrial fibrillation patients. Overall, the pathogenesis linking atrial fibrillation to dementia is likely multifactorial. Cerebral infarctions, including silent stroke, play a central role. These findings underscore the importance of stroke prevention measures in atrial fibrillation patients.

Impact of Atrial Fibrillation on Cognitive Function, Psychological Distress, Quality of Life, and Impulsiveness

OBJECTIVE

Atrial fibrillation is the most common cardiac arrhythmia and a known risk factor for cerebrovascular stroke. Atrial fibrillation and longstanding hypertension may produce ischemic lesions leading to progressive cognitive impairment. The impact of atrial fibrillation alone on cognitive impairment has not been evaluated. Our objective was to compare cognitive function, quality of life, psychological distress, and impulsiveness in people with atrial fibrillation and a matched control group.

METHODS

The study included 60 patients. The first group of patients were ≥55 years of age, with ≥5 years history of atrial fibrillation, without hypertension (or with well-controlled hypertension), without previous dementia, compared with a matched group of 30 healthy control participants. Demographic and clinical characteristics were recorded. Subjects underwent the following rating scales: Mini-Mental State Examination, Hospital Anxiety and Depression, Heart Quality of Life, and Barratt Impulsiveness Scale.

RESULTS

In the atrial fibrillation group there were 63% male (n = 19) and 37% female (n = 11) patients; the control group was 33% male (n = 10) and 67% female (n = 20). Age range was from 55 to 81 years in both groups, mean = 63.9 years (±6.4) in the atrial fibrillation group and 66.1 years (±8.0) in controls. In the atrial fibrillation group, 23.3% had primary or general education, college - 23.3% and university - 53.3%; in the control group - 20%, 23.3%, and 56.7%, respectively. Mini-Mental State Examination score was 27.6 (±1.6) in the atrial fibrillation group vs 29.5 (±0.73) in the control group (P < .0001). Anxiety disorders were observed in 20 patients (66.7%) in atrial fibrillation vs 8 patients (26.67%) in the control group (P = .009). Heart Quality of Life mean score was 1.4 (±0.65) in the atrial fibrillation and 2.6 (±0.35) in the control group (P < .0001). Physical subscale mean scores were 1.4 (±0.74) in atrial fibrillation vs 2.8 (±0.18) in the control group (P < .0001).

CONCLUSION

Individuals with atrial fibrillation are more likely to develop anxiety disorder. Cognitive status is significantly lower in the atrial fibrillation group. In comparison with healthy subjects, individuals with atrial fibrillation have worse quality of life.

Alteration of cerebrovascular haemodynamic patterns due to atrial fibrillation: an in silico investigation

There has recently been growing evidence that atrial fibrillation (AF), the most common cardiac arrhythmia, is independently associated with the risk of dementia. This represents a very recent frontier with high social impact for the number of individuals involved and for the expected increase in AF incidence in the next 40 years. Although a number of potential haemodynamic processes, such as microembolisms, altered cerebral blood flow, hypoperfusion and microbleeds, arise as connecting links between the two pathologies, the causal mechanisms are far from clear. An in silico approach is proposed that combines in sequence two lumped-parameter schemes, for the cardiovascular system and the cerebral circulation. The systemic arterial pressure is obtained from the cardiovascular system and used as the input for the cerebral circulation, with the aim of studying the role of AF on the cerebral haemodynamics with respect to normal sinus rhythm (NSR), over a 5000 beat recording. In particular, the alteration of the haemodynamic (pressure and flow rate) patterns in the microcirculation during AF is analysed by means of different statistical tools, from correlation coefficients to autocorrelation functions, crossing times, extreme values analysis and multivariate linear regression models. A remarkable signal alteration, such as a reduction in signal correlation (NSR, about 3 s; AF, less than 1 s) and increased probability (up to three to four times higher in AF than in NSR) of extreme value events, emerges for the peripheral brain circulation. The described scenario offers a number of plausible cause-effect mechanisms that might explain the occurrence of critical events and the haemodynamic links relating to AF and dementia.

From time-series to complex networks: Application to the cerebrovascular flow patterns in atrial fibrillation

A network-based approach is presented to investigate the cerebrovascular flow patterns during atrial fibrillation (AF) with respect to normal sinus rhythm (NSR). AF, the most common cardiac arrhythmia with faster and irregular beating, has been recently and independently associated with the increased risk of dementia. However, the underlying hemodynamic mechanisms relating the two pathologies remain mainly undetermined so far; thus, the contribution of modeling and refined statistical tools is valuable. Pressure and flow rate temporal series in NSR and AF are here evaluated along representative cerebral sites (from carotid arteries to capillary brain circulation), exploiting reliable artificially built signals recently obtained from an in silico approach. The complex network analysis evidences, in a synthetic and original way, a dramatic signal variation towards the distal/capillary cerebral regions during AF, which has no counterpart in NSR conditions. At the large artery level, networks obtained from both AF and NSR hemodynamic signals exhibit elongated and chained features, which are typical of pseudo-periodic series. These aspects are almost completely lost towards the microcirculation during AF, where the networks are topologically more circular and present random-like characteristics. As a consequence, all the physiological phenomena at the microcerebral level ruled by periodicity-such as regular perfusion, mean pressure per beat, and average nutrient supply at the cellular level-can be strongly compromised, since the AF hemodynamic signals assume irregular behaviour and random-like features. Through a powerful approach which is complementary to the classical statistical tools, the present findings further strengthen the potential link between AF hemodynamic and cognitive decline.

Uncovering brain-heart information through advanced signal and image processing

Through their dynamical interplay, the brain and the heart ensure fundamental homeostasis and mediate a number of physiological functions as well as their disease-related aberrations. Although a vast number of ad hoc analytical and computational tools have been recently applied to the non-invasive characterization of brain and heart dynamic functioning, little attention has been devoted to combining information to unveil the interactions between these two physiological systems. This theme issue collects contributions from leading experts dealing with the development of advanced analytical and computational tools in the field of biomedical signal and image processing. It includes perspectives on recent advances in 7 T magnetic resonance imaging as well as electroencephalogram, electrocardiogram and cerebrovascular flow processing, with the specific aim of elucidating methods to uncover novel biological and physiological correlates of brain-heart physiology and physiopathology.

Atrial fibrillation, cognitive impairment, and neuroimaging

INTRODUCTION

The objective of our study was to investigate cross-sectional associations of atrial fibrillation with neuroimaging measures of cerebrovascular disease and Alzheimer's disease and their interactions with mild cognitive impairment (MCI).

METHODS

Magnetic resonance imaging scans of individuals from a population-based study were analyzed for infarctions, total gray matter, and hippocampal and white matter hyperintensity volumes. A subsample underwent positron emission tomography imaging.

RESULTS

Atrial fibrillation was associated with infarctions and lower total gray matter volume. Compared with subjects with no atrial fibrillation and no infarction, the odds ratio (95% confidence intervals) for MCI was 2.99 (1.57-5.70; P = .001) among participants with atrial fibrillation and infarction, 0.90 (0.45-1.80; P = .77) for atrial fibrillation and no infarction, and 1.50 (0.96-2.34; P = .08) for no atrial fibrillation and any infarction.

DISCUSSION

Participants with both atrial fibrillation and infarction are more likely to have MCI than participants with either infarction or atrial fibrillation alone.

Cognitive impairment and cardiovascular diseases in the elderly. A heart-brain continuum hypothesis

The aging population is increasing and, therefore, a higher prevalence of cardiac disease is emerging; including hypertension, coronary artery disease, atrial fibrillation and chronic heart failure. Large cohort studies have revealed a relationship among increased risk for cognitive impairment and dementia in cardiovascular diseases probably due to embolic stroke or chronic cerebral hypoperfusion. Thus, the aim of the present review is to overview the studies that investigate the presence and/or the development of cognitive impairments and dementia in patients with varied types of cardiovascular disease. Finally, a continuum among hypertension, coronary artery disease, atrial fibrillation and chronic heart failure with to the development of cognitive impairment and progression to dementia has been hypothesized.

Cardiovascular disease and cognitive decline in postmenopausal women: results from the Women's Health Initiative Memory Study

BACKGROUND

Data on cardiovascular diseases (CVD) and cognitive decline are conflicting. Our objective was to investigate if CVD is associated with an increased risk for cognitive decline and to examine whether hypertension, diabetes, or adiposity modify the effect of CVD on cognitive functioning.

METHODS AND RESULTS

Prospective follow-up of 6455 cognitively intact, postmenopausal women aged 65 to 79 years old enrolled in the Women's Health Initiative Memory Study (WHIMS). CVD was determined by self-report. For cognitive decline, we assessed the incidence of mild cognitive impairment (MCI) or probable dementia (PD) via modified mini-mental state examination (3 MS) score, neurocognitive, and neuropsychiatric examinations. The median follow-up was 8.4 years. Women with CVD tended to be at increased risk for cognitive decline compared with those free of CVD (hazard ratio [HR], 1.29; 95% CI: 1.00, 1.67). Women with myocardial infarction or other vascular disease were at highest risk (HR, 2.10; 95% CI: 1.40, 3.15 or HR, 1.97; 95% CI: 1.34, 2.87). Angina pectoris was moderately associated with cognitive decline (HR 1.45; 95% CI: 1.05, 2.01) whereas no significant relationships were found for atrial fibrillation or heart failure. Hypertension and diabetes increased the risk for cognitive decline in women without CVD. Diabetes tended to elevate the risk for MCI/PD in women with CVD. No significant trend was seen for adiposity.

CONCLUSIONS

CVD is associated with cognitive decline in elderly postmenopausal women. Hypertension and diabetes, but not adiposity, are associated with a higher risk for cognitive decline. More research is warranted on the potential of CVD prevention for preserving cognitive functioning.

Atrial Fibrillation - A Common Ground for Neurology and Cardiology

Atrial fibrillation (AF) has a huge impact on clinical stroke because it is the primary cause of cardio-embolism, which constitutes ~20% of all strokes. As a result, there is a great need to explore safer and more effective primary and secondary prophylactic agents. In this article, we discuss the overlapping issues pertaining to AF from both a neurology and cardiology standpoint. We focus on the dynamic interplay of neurovascular and cardiovascular diseases in relation to AF, traditional and novel risk factors for AF leading to stroke, impact of AF on cognitive decline, and current upstream medical and surgical options for embolism prophylaxis.

Improved neurocognitive functions correlate with reduced inflammatory burden in atrial fibrillation patients treated with intensive cholesterol lowering therapy

Background

Atrial fibrillation (AF) is associated with increased mortality and morbidity, including risk for cerebral macro- and microinfarctions and cognitive decline, even in the presence of adequate oral anticoagulation. AF is strongly related to increased inflammatory activity whereby anti-inflammatory agents can reduce the risk of new or recurrent AF. However, it is not known whether anti-inflammatory therapy can also modify the deterioration of neurocognitive function in older patients with AF. In the present study, older patients with AF were treated with intensive lipid-lowering therapy with atorvastatin 40 mg and ezetimibe 10 mg, or placebo. We examined the relationship between neurocognitive functions and inflammatory burden.

Findings

Analysis of inflammatory markers revealed significant reductions in high sensitivity C-reactive protein (hs-CRP), fibroblast growth factor (FGF), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 receptor antagonist (IL-1RA), interleukin (IL)-9, IL-13 and IL-17, and interferon-γ (IFNγ) in the treatment group compared to placebo. Reduction in plasma concentration of IL-1RA, IL-2, IL-9 and IL-12, and macrophage inflammatory protein-1β (MIP-1β) correlated significantly with improvement in the neurocognitive functions memory and speed. Loss of volume in amygdala and hippocampus, as determined by magnetic resonance imaging (MRI), was reduced in the treatment arm, statistically significant for left amygdala.

Conclusions

Anti-inflammatory therapy through intensive lipid-lowering treatment with atorvastatin 40 mg and ezetimibe 10 mg can modify the deterioration of neurocognitive function, and the loss of volume in certain cerebral areas in older patients with AF.

Trial registration Clinical Trials.gov

NCT00449410

Atrial fibrillation and cognitive decline: a longitudinal cohort study

OBJECTIVE

We sought to determine whether in the absence of clinical stroke, people with atrial fibrillation experience faster cognitive decline than people without atrial fibrillation.

METHODS

We conducted a longitudinal analysis in the Cardiovascular Health Study, a community-based study of 5,888 men and women aged 65 years and older, enrolled in 1989/1990 or 1992/1993. Participants did not have atrial fibrillation or a history of stroke at baseline. Participants were censored when they experienced incident clinical stroke. Incident atrial fibrillation was identified by hospital discharge diagnosis codes and annual study ECGs. The main outcome was rate of decline in mean scores on the 100-point Modified Mini-Mental State Examination (3MSE), administered annually up to 9 times.

RESULTS

Analyses included 5,150 participants, of whom 552 (10.7%) developed incident atrial fibrillation during a mean of 7 years of follow-up. Mean 3MSE scores declined faster after incident atrial fibrillation compared with no prior atrial fibrillation. For example, the predicted 5-year decline in mean 3MSE score from age 80 to age 85 was -6.4 points (95% confidence interval [CI]: -7.0, -5.9) for participants without a history of atrial fibrillation, but was -10.3 points (95% CI: -11.8, -8.9) for participants experiencing incident atrial fibrillation at age 80, a 5-year difference of -3.9 points (95% CI: -5.3, -2.5).

CONCLUSIONS

In the absence of clinical stroke, people with incident atrial fibrillation are likely to reach thresholds of cognitive impairment or dementia at earlier ages than people with no history of atrial fibrillation.

Heart disease as a risk factor for dementia

As life expectancy lengthens, dementia is becoming a significant human condition in terms of its prevalence and cost to society worldwide. It is important in that context to understand the preventable and treatable causes of dementia. This article exposes the link between dementia and heart disease in all its forms, including coronary artery disease, myocardial infarction, atrial fibrillation, valvular disease, and heart failure. This article also explores the cardiovascular risk factors and emphasizes that several of them are preventable and treatable. In addition to medical therapies, the lifestyle changes that may be useful in retarding the onset of dementia are also summarized.

Transitions of care in anticoagulation management for patients with atrial fibrillation

Thromboprophylaxis with oral anticoagulants (OACs) is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk with anticoagulants comes at the price of increased bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another. Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the OAC, administering vitamin K, when appropriate, to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of OACs in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant. Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by both AF and aging are goals for all patients receiving OACs. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, or particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, and long-term care settings are vital for patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.

Point-of-care screening to identify cognitive impairment in older adults

OBJECTIVE

To explore associations between results of a rapid screening tool for cognitive impairment and individual patient characteristics in a sample of patients receiving outpatient anticoagulation therapy who were not previously diagnosed with a dementia.

DESIGN

Descriptive, nonexperimental, cross-sectional study.

SETTING

Pharmacist-managed anticoagulation clinic in Spokane, WA, from June 2006 to March 2007.

PARTICIPANTS

300 community-dwelling patients aged 60 years or older who had at least 6 months of outpatient anticoagulation therapy services.

INTERVENTION

Following informed consent, demographic, medical history, medication history, anticoagulation therapy, and cognitive screening data were recorded from participant medical records, and a participant interview was performed using a standardized questionnaire and data collection form.

MAIN OUTCOME MEASURES

Cognitive screening status (suggests cognitive impairment versus suggests dementia less likely) was used as an independent variable by which to compare patient demographics, medical history, medication history, and percent of out-of-range International Normalized Ratio (INR) visits.

RESULTS

55 of 300 participants (18.3%) with no previous diagnosis of a cognitive impairment were classified as "suggests cognitive impairment" based on the screening test. Presence or absence of cognitive impairment differed in those needing assistance with taking medications but was not associated with other sample characteristics, including percentage of visits with out-of-range INR value, gender, in-home care needs, age, and number of medical conditions.

CONCLUSION

Screening at a convenient health care access point may lead to increased identification of community-dwelling elderly patients with unrecognized and undiagnosed cognitive impairment. Pharmacists are particularly well suited to conduct this screening because of the extended and frequent contact they have with patients in settings such as anticoagulation therapy clinics.

Microembolism, silent brain infarcts and dementia

Cognitive decline becomes more prevalent than ever in parallel with the increasing life expectancy of the population. Alzheimer' disease (AD) and cerebral vascular lesions are common in the elderly and represent, with increased age, the most frequent contributors to cognitive decline. It is now believed that these pathologies frequently coexist in the same brain. The border discriminating vascular dementia from AD is blurred and challenges our understanding of these clinical entities. Further research, at both basic and clinical levels, is mandatory in order to better understand the interactions of vascular ischemic injury and primary degenerative physiopathologies of the brain, in order to prevent and better manage patients with cognitive decline. We review recent published clinical evidence of silent brain ischemia as a contributor to cognitive decline and dementia. Microemboli, from both cardiac and vascular origins, have been shown to be associated with structural changes in the brain. The role of transcranial Doppler as an objective tool for detecting and quantifying microemboli is discussed in light of recent clinical evidence.

Increased risk of cognitive and functional decline in patients with atrial fibrillation: results of the ONTARGET and TRANSCEND studies

BACKGROUND

The role of atrial fibrillation in cognitive impairment and dementia, independent of stroke, is uncertain. We sought to determine the association of atrial fibrillation with cognitive and physical impairment in a large group of patients at high cardiovascular risk.

METHODS

We conducted a post-hoc analysis of two randomized controlled trials involving 31,546 patients, the aims of which were to evaluate the efficacy of treatment with ramipril plus telmisartan (ONTARGET) or telmisartan alone (TRANSCEND) in reducing cardiovascular disease. We evaluated the cognitive function of participants at baseline and after two and five years using the Mini-Mental State Examination (MMSE). In addition, we recorded incident dementia, loss of independence in activities of daily living and admission to long-term care facilities. We used a Cox regression model adjusting for main confounders to determine the association between atrial fibrillation and our primary outcomes: a decrease of three or more points in MMSE score, incident dementia, loss of independence in performing activities of daily living and admission to long-term care.

RESULTS

We enrolled 31,506 participants for whom complete information on atrial fibrillation was available, 70.4% of whom were men. The mean age of participants was 66.5 years, and the mean baseline MMSE score was 27.7 (standard deviation 2.9) points. At baseline, 1016 participants (3.3%) had atrial fibrillation, with the condition developing in an additional 2052 participants (6.5%) during a median follow-up of 56 months. Atrial fibrillation was associated with an increased risk of cognitive decline (hazard ratio [HR] 1.14, 95% confidence interval [CI] 1.03-1.26), new dementia (HR 1.30, 95% CI 1.14-1.49), loss of independence in performing activities of daily living (HR 1.35, 95% CI 1.19-1.54) and admission to long-term care facilities (HR 1.53, 95% CI 1.31-1.79). Results were consistent among participants with and without stroke or receiving antihypertensive drugs.

INTERPRETATION

Cognitive and functional decline are important consequences of atrial fibrillation, even in the absence of overt stroke.

Atrial fibrillation predicts cognitive impairment in patients with ischemic stroke

BACKGROUND

Atrial fibrillation (AF) is considered as a risk factor for cognitive impairment.

METHODS

This retrospective chart review study was conducted in a patient stroke rehabilitation ward of a university-affiliated referral hospital. The participants were 707 patients admitted for a standard rehabilitation course after an ischemic stroke. Cognitive status was assessed by the Mini-Mental State Examination (MMSE), and scores lower than 24 points were considered as suggestive of cognitive impairment.

RESULTS

Atrial fibrillation, age, gender, diabetes, and dementia emerged as the only statistically significant parameters differing between those with MMSE score lower than 24 or higher. In a multiple logistic regression analysis, AF (odds ratio 1.6, 95% confidence interval 1.03-2.47, P = .03) was associated with an increased risk of cognitive impairment.

CONCLUSIONS

Our findings suggest that atrial fibrillation upon admission is independently associated with lower MMSE scores in patients with ischemic stroke.

Cognitive dysfunctions in intensive cardiac care unit

BACKGROUND

Cognitive impairment is gaining recognition as sequelae of heart failure and the ICCU environment adds to their worsening symptoms.

OBJECTIVES

To determine cognitive dysfunctions in patients with heart disease admitted in intensive cardiac care unit (ICCU) and to compare it with patients admitted in general medical wards with heart disease.

MATERIALS AND METHODS

A total of 30 patients admitted to ICCU with heart disease were taken for the study and compared to patients with heart disease admitted in general medicine wards (except ICCU). The tools used were SMMSE (Standardized Mini Mental State Examination) and BCRS (Brief Cognitive Rating Scale). Statistical tests used were Student 't' test and Chi-Square test.

RESULTS

This study showed cognitive dysfunctions in the domains of orientation, attention and constructional ability as measured by SMMSE and cognitive dysfunction in the domain of concentration as measured by BCRS. Overall cognitive dysfunctions were present in the total score of both SMMSE and BCRS scale, which was statistically very highly significant.

CONCLUSION

The results showed that the patients in ICCU had cognitive dysfunctions in the domains of orientation, attention, constructional ability and concentration. Overall cognitive dysfunctions were found in the total scores of SMMSE and BCRS, thus signifying a global cognitive deficit.

Short-term and long-term success of electrical cardioversion in atrial fibrillation in managed care system

Background

Initial success of electrical cardioversion (ECV) of atrial fibrillation (AF) has been reported in several studies as 50%-90%, of which only 50% patients remain in sinus rhythm (SR) at the end of one year. We conducted this study to see if outcomes of other trials are applicable in managed care setting.

Methods

We conducted a retrospective study in 370 consecutive patients who underwent ECV for AF. They were reviewed for initial outcome of ECV and recurrence of AF after a successful ECV, with and without prophylactic antiarrhythmic drugs.

Results

Initial success of ECV for AF was 65.7%. At one year, 47% remained in SR. AF for ≤ 3 months (p = 0.006) and pretreatment with antiarrhythmic drugs (p = 0.032) resulted in improved success. Predictors of recurrence were patients ≤ 65 years (p = 0.019), paroxysmal atrial fibrillation (PAF) (p = 0.0094) and alcohol consumption (p = 0.0074).

Conclusion

Shorter duration of AF, prophylactic antiarrhythmic drugs and serial ECVs improve outcome of ECV in AF. For younger patients with PAF and alcohol consumption, due to higher recurrence of AF, rate control or ablative therapy may be the preferred strategy.

Atrial fibrillation is associated with lower cognitive performance in the Framingham offspring men

The purpose of this study was to investigate the association of atrial fibrillation (AFIB) with multiple measures of cognitive performance in a large community-based sample extensively characterized for vascular risk factors. Our primary analysis included 1011 Framingham Offspring Study (Framingham, Mass) men, mean age = 61.0 (37-89) years, free of clinical stroke and dementia. Using multivariable linear regression models, we related the presence (n = 59) versus absence (n = 952) of AFIB in men to a global measure of performance and multiple measures of specific cognitive abilities assessed an average of 8 months after the AFIB surveillance period. Adjusting for age, education, multiple cardiovascular risk factors, and cardiovascular disease, men with AFIB exhibited significantly lower mean levels of cognitive performance compared with men in normal sinus rhythm. Men with AFIB exhibited lower performance on global cognitive ability and cognitive abilities including Similarities (abstract reasoning), Visual Reproductions-Immediate Recall, Visual Reproductions-Delayed Recall, Visual Organization, Logical Memory-Delayed Recall, and Trail Making A (scanning and tracking) and Trail Making B (scanning, tracking, and executive functioning). Further studies leading to a better understanding of the mechanisms underlying the relation between AFIB and cognitive performance are important.

Vascular risk factors, cognitive decline, and dementia

Dementia is one of the most important neurological disorders in the elderly. Aging is associated with a large increase in the prevalence and incidence of degenerative (Alzheimer's disease) and vascular dementia, leading to a devastating loss of autonomy. In view of the increasing longevity of populations worldwide, prevention of dementia has turned into a major public health challenge. In the past decade, several vascular risk factors have been found to be associated with vascular dementia but also Alzheimer's disease. Some longitudinal studies, have found significant associations between hypertension, diabetus mellitus, and metabolic syndrome, assessed at middle age, and dementia. Studies assessing the link between hypercholesterolemia, atrial fibrillation, smoking, and dementia have given more conflicting results. Furthermore, some studies have highlighted the possible protective effect of antihypertensive therapy on cognition and some trials are evaluating the effects of statins and treatments for insulin resistance. Vascular risk factors and their treatments are a promising avenue of research for prevention of dementia, and further long-term, placebo-controlled, randomized studies, need to be performed.

The routine electrocardiogram for cardiovascular risk stratification in old age: the Leiden 85-plus study

OBJECTIVES

To explore the prognostic value of signs of prior myocardial infarction (MI) and atrial fibrillation (AF) on routine electrocardiograms (ECGs) at the age of 85 with respect to mortality and changes in functional status.

DESIGN

Observational, prospective cohort study with complete 6-year follow-up.

SETTING

General population.

PARTICIPANTS

A population-based sample of 566 85-year-old participants (377 women, 189 men), without exclusion criteria.

MEASUREMENTS

Annual ECG recording and evaluation using automated Minnesota Coding; annual assessment of functional status using validated questionnaires and tests; complete mortality data from civic and national registries.

RESULTS

Participants with prior MI at the age of 85 (prevalence 9%) showed greater all-cause mortality (relative risk (RR)=1.7, 95% confidence interval (CI)=1.2-2.2) and cardiovascular mortality (RR=2.5, 95% CI=1.6-3.8) but no accelerated decline in functional status during follow-up. Participants with AF at the age of 85 (prevalence 10%) showed greater all-cause (RR=1.5, 95% CI=1.2-2.0) and cardiovascular (RR=2.0, 95% CI=1.3-3.0) mortality, as well as an accelerated decline in functional status during follow-up.

CONCLUSION

Very elderly people with prior MI or AF on a routine ECG have markedly greater (cardiovascular) mortality risks. In addition, AF, but not prior MI, is associated with accelerated decline in functional status. These findings suggest that older patients with occasional findings of prior MI or AF on a routine ECG should receive optimal secondary preventive therapy. Furthermore, programmatic ECG recording could be of significant value for cardiovascular risk stratification in old age and needs further exploration.

Atrial fibrillation and risk of dementia in non-demented elderly subjects with and without mild cognitive impairment (MCI)

MCI is regarded as a precursor of dementia, but not all patients with MCI actually develop dementia. As Alzheimer and vascular dementia (AD and VD, respectively) are thought to share many common etiopathogenetic mechanisms, we investigated whether the vascular risk factor atrial fibrillation affect the risk of conversion to dementia for different MCI subtypes diagnosed according to international criteria. One-hundred-eighty elderly outpatients with MCI and 431 elderly outpatients with a normal cognition were followed-up for a mean of 3 and 4 years, respectively. The risk of conversion to dementia associated with atrial fibrillation was studied in both samples using a Cox proportional-hazards model adjusted for sociodemographic and medical variables. Overall conversion rate to dementia was 10.5 (8.0-13.8) per 100 person-years in the MCI group and 2.2 (1.5-3.1) per 100 person-years in the normal cognition group. Atrial fibrillation was significantly associated with conversion to dementia (hazard ratio=HR=4.63, 95% confidence interval=Cl=1.72-12.46) in the MCI group, but not in the cognitively normal group (HR=1.10, 95% Cl=0.40-3.03). Current diagnostic criteria for MCI subtypes define heterogeneous populations, but atrial fibrillation can be useful in identifying people with increased risk of conversion to dementia.

Risk of dementia in stroke-free patients diagnosed with atrial fibrillation: data from a community-based cohort

AIMS

To estimate the incidence of dementia after the first atrial fibrillation (AF), and its impact on survival in a community-based cohort.

METHODS AND RESULTS

Olmsted County, Minnesota adult residents diagnosed with first AF during 1986-2000 were identified, and followed until 2004. The primary outcome was new detection of dementia. Interim stroke was censored in the analyses. Of 2837 subjects (71 +/- 15 years old) diagnosed with first AF and without any evidence of cognitive dysfunction or stroke at the time of AF onset, 299 were diagnosed with dementia during a median follow-up of 4.6 years [interquartile (IQR) range 1.5-7.9 years], and 1638 died. The Kaplan-Meier cumulative rate of dementia was 2.7% at 1 year and 10.5% at 5 years. After adjustment for age and sex, dementia was strongly related to advancing age [hazard ratio (HR)/10 years, 2.8; 95% confidence interval (CI), 2.5-3.2], but did not vary with sex (P = 0.52). The occurrence of post-AF dementia was associated with significantly increased mortality risk (HR 2.9; 95% CI 2.5-3.3), even after adjustment for multiple comorbidities, and did not vary with age (P = 0.75) or sex (P = 0.33).

CONCLUSION

Dementia appeared common following the diagnosis of first AF, and was associated with premature death.

A review of the literature on atrial fibrillation: rate reversion or control?

AIMS

The aim of this paper is to review the current literature describing the aetiology of atrial fibrillation and to examine the evidence for rate reversion and rate control.

BACKGROUND

Atrial fibrillation is the most commonly seen arrhythmia within the clinical setting. Treatment depends on severity of symptoms, which are predominantly palpitations and shortness of breath. The primary complications from atrial fibrillation are thrombo-embolic events (such as a pulmonary embolus or stroke).

OBJECTIVES AND METHODS

A comprehensive literature review on atrial fibrillation, rate reversion and rate control was undertaken to examine the incidence of atrial fibrillation, to review research on management of atrial fibrillation and to determine if rate reversion was superior to rate control in the treatment of atrial fibrillation.

RESULTS

Many studies have been carried out to determine the best treatment for this condition. The choices are currently pharmacological and electrical cardioversion in conjunction with anticoagulant therapy. Drug therapies are not without their problems, especially toxicity and the need for close clinical monitoring. Transaesophageal echocardiography has been used to establish the presence of left atrial thrombi and aims to reduce the anticoagulation time and reduce the risk of thrombo-embolic events. A randomized comparative study of transaesophageal echocardiography and conventional anticoagulation therapy prior to cardioversion demonstrated statistically significant reduction in haemorrhagic events and a shorter time to cardioversion in those in the transaesophageal echocardiography group compared with the conventional group. For those with persistent atrial fibrillation, surgery is an option with valve repair or replacement carried out in conjunction with a bi-atrial surgical ablation.

CONCLUSIONS

The management of atrial fibrillation is dependent on many factors and to date there are no proven clinical rationale for rate control or reversion.

RELEVANCE TO CLINICAL PRACTICE

Atrial fibrillation requires immediate attention in order to avoid thrombo-embolic complications and the use of transaesophageal echocardiography and conventional anticoagulation therapy can significantly reduce these complications.

Atrial fibrillation and risk of dementia in non-demented elderly subjects with and without mild cognitive impairment

OBJECTIVES

Mild cognitive impairment (MCI) is regarded as a precursor to dementia, but not all patients with MCI actually develop dementia. As Alzheimer and vascular dementia are thought to share many common etiopathogenetic mechanisms, we investigated whether the vascular risk factor atrial fibrillation affects the risk of conversion to dementia for different MCI subtypes diagnosed according to international criteria.

METHODS

One hundred and eighty elderly outpatients with MCI and 431 elderly outpatients with a normal cognition were followed up for a mean of 3 and 4 years, respectively. The risk of conversion to dementia associated with atrial fibrillation was studied in both samples using a Cox proportional hazards model adjusted for socio-demographic and medical variables.

RESULTS

Overall conversion rate to dementia was 10.5 (8.0-13.8 per 100 person-years) in the MCI group and 2.2 (1.5-3.1 per 100 person-years) in the normal cognition group. Atrial fibrillation was significantly associated with conversion to dementia [hazard ratio (HR): 4.63; 95% confidence interval: 1.72-12.46] in the MCI group but not in the cognitively normal group (HR: 1.10; 95% confidence interval: 0.40-3.03).

DISCUSSION

Current diagnostic criteria for MCI subtypes define heterogeneous populations, but atrial fibrillation can be useful in identifying people with increased risk of conversion to dementia.

Frequency and clinical determinants of poststroke cognitive impairment in nondemented stroke patients

The objective of this study was to examine the prevalence and clinical correlates of poststroke cognitive impairment in Chinese stroke patients in Hong Kong. One hundred seventy-nine stroke patients were interviewed by a psychiatrist 3 months after their stroke. Cognitive impairment was determined according to the Mini-Mental State Examination score. Thirty-nine participants (21.8%) had cognitive impairment. Univariate analysis found that cognitive impairment was associated with age, female sex, level of education, previous stroke, prestroke Rankin score, National Institutes of Health Stroke Scale dysarthria and total scores, urinary incontinence, and cerebral atrophy index. Multivariate logistic regression suggested that female sex, education, National Institutes of Health Stroke Scale dysarthria score, urinary incontinence, and atrial fibrillation were independent risk factors of poststroke cognitive impairment. After removal of 54 patients with previous stroke from the sample, the frequency of cognitive impairment decreased to 18.4%. It was concluded that cognitive impairment is common among nondemented Chinese stroke patients in Hong Kong.

Conversion of mild cognitive impairment to dementia: predictive role of mild cognitive impairment subtypes and vascular risk factors

Mild cognitive impairment (MCI) is regarded as a precursor to dementia, but not all patients with MCI develop dementia. We followed up 165 elderly outpatients with MCI for a mean of 3 years. The aims were (1) to investigate the risk of conversion to dementia for different MCI subtypes diagnosed according to standardized criteria (amnestic; impairment of memory plus other cognitive domains; nonamnestic); (2) to assess whether the risk of conversion was affected by several established and emerging vascular risk factors. Forty-eight subjects (29%) converted to dementia, and the risk of conversion was doubled for amnestic MCI with respect to the other subtypes. Independently of MCI subtype, risk of conversion was associated with atrial fibrillation and low serum folate levels. Our results show that current diagnostic criteria for MCI define heterogeneous populations, but some potentially treatable vascular risk factors may be of help in predicting conversion to dementia.

Functional Status in Rate- Versus Rhythm-Control Strategies for Atrial Fibrillation

OBJECTIVES

The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) functional status substudy aimed to test the hypothesis that functional status is similar in rate-control and rhythm-control strategies.

BACKGROUND

Randomized studies, including the AFFIRM study, have failed to demonstrate survival benefits between rate-control and rhythm-control strategies for atrial fibrillation (AF). However, AF may cause functional capacity or cognitive impairment that might justify maintenance of sinus rhythm.

METHODS

Investigators of the AFFIRM study enrolled 4,060 patients with AF who required long-term therapy and who were 65 years of age or older or who had another risk factor for stroke or death. New York Heart Association functional class (NYHA-FC) and Canadian Cardiovascular Society Angina Classification were assessed at initial and each follow-up visit. From 22 randomly chosen functional status substudy sites, 245 participants underwent 6-min walk tests and Mini-Mental State Examination (MMSE) at initial, two-month, and yearly visits. Patients were assigned randomly to rate-controlling drugs, allowing AF to persist, or rhythm-controlling antiarrhythmic drugs, to maintain sinus rhythm.

RESULTS

The NYHA-FC worsened with time in both rate-control and rhythm-control groups, with no differences between groups. Presence of AF was associated with worse NYHA-FC (p < 0.0001). No differences were observed in Canadian Cardiovascular Society Angina Classification or MMSE scores. Six-minute walk distance improved over time in both study arms. On average, walk distance was 94 feet greater in the rhythm-control group (adjusted p = 0.049).

CONCLUSIONS

Modest improvement in 6-min walk distance was noted in the rhythm-control arm. Presence of AF was associated with worse NYHA-FC. No difference in cognitive function was detected.

Prestroke dementia in patients with atrial fibrillation

BACKGROUND AND PURPOSE

Prestroke dementia is frequent but usually not identified. Non-valvular atrial fibrillation (NVAF) is independently associated with an increased risk for dementia. However, the frequency and determinants of prestroke dementia in patients with NVAF have never been evaluated.

OBJECTIVE

The aim of this study was to determine the frequency of prestroke dementia and associated factors in patients with a previously known NVAF.

METHODS

This is an ancillary study of Stroke in Atrial Fibrillation Ensemble II (SAFE II), an observational study conducted in patients with a previously known NVAF, consecutively admitted for an acute stroke in French and Italian centers. Prestroke dementia was evaluated by the IQCODE in patients with a reliable informant. Patients were considered as demented before stroke when their IQCODE score was > or = 104.

RESULTS

of 204 patients, 39 (19.1%; 95% confidence interval [CI]: 13.7%-24.5%) patients met criteria for prestroke dementia. The only variable independently associated with prestroke dementia was increasing age (adjusted odds ratio for 1 year increase in age: 1.10; 95 % CI: 1.04-1.17), and there was a nonsignificant tendency for previous ischemic stroke or TIA and arterial hypertension.

CONCLUSION

One fifth of stroke patients with a previously known NVAF were already demented before stroke. The main determinant of prestroke dementia is increasing age. A large cohort is necessary to identify other determinants.

Cognitive Impairment as Determinant for Sub-Optimal Control of Oral Anticoagulation Treatment in Elderly Patients with Atrial Fibrillation

BACKGROUND AND OBJECTIVE

Atrial fibrillation is an indication for oral anticoagulation treatment. Maintaining the International Normalized Ratio (INR) within the therapeutic range minimises thromboembolic and bleeding complications. We have investigated whether cognitive capacity affects control of anticoagulation in elderly patients with atrial fibrillation.

PATIENTS AND METHODS

A retrospective study was conducted to investigate the association between cognitive impairment and control of anticoagulation. Patients > or =70 years of age with atrial fibrillation using acenocoumarol (nicoumalone) as anticoagulant were included. All patients were monitored by the Anticoagulation Clinic in the Midden-Brabant region in the Netherlands. The cognitive function of all patients was assessed using the Mini-Mental State Examination (MMSE) on the index date. INR values were obtained from the year preceding the index date. Patients with an MMSE score <23 were defined as cognitively impaired. The primary outcome of the study was the incidence of an INR value within the therapeutic range of 2.0-3.4 during < or =70% of treatment time in the year prior to the cognitive function assessment. The secondary endpoint was the number of patients with an INR <2.0 or > or =6.0 at least once during this year. Logistic regression analysis was used to evaluate the association between cognitive function and control of anticoagulation.

RESULTS

A total of 152 patients were included in the study. An MMSE score <23 was associated with an inadequate INR control (odds ratio [OR] 2.77; 95% CI 1.13, 6.74). After correction for hospital admission and change of possibly interacting medication (both also associated with inadequate INR control), this association remained statistically significant. Significantly more patients with an MMSE score <23 had one or more INR values of six or higher (OR 3.06; 95% CI 1.14, 8.18).

CONCLUSION

In elderly people with atrial fibrillation using oral anticoagulation, an MMSE score <23 is independently associated with an inadequate INR control, mainly because of an increased number of supratherapeutic INR values. This finding should be taken into account when making decisions about use of oral anticoagulants in the elderly.

Blunted reduction in night-time blood pressure is associated with cognitive deterioration in subjects with long-standing hypertension

OBJECTIVE

Data about the relationship of blunted reduction of night-time blood pressure (BP) with cognitive deterioration (CD) are conflicting. This study aims to explore this possible association in elderly people with long-standing hypertension.

METHODS

Twenty-six hypertensive subjects consecutively admitted to a rehabilitation unit over a six-month period were recruited. Exclusion criteria concerned all clinical conditions potentially related to BP variability or leading to CD. All patients underwent a clinic and 24-h BP non-invasive monitoring assessment of BP, as well as a cognitive assessment with the Mini Mental State Examination (MMSE). The presence of cerebrovascular disease (CVD) was assessed on CT films, with a standardized visual rating scale.

RESULTS

Blunted reduction of both systolic and diastolic night-time BP were significantly associated with poorer cognitive performances (r=0.61, p=0.001 for systolic; and r=0.57, p=0.002 for diastolic, respectively). In a multiple regression model, blunted reduction of night-time BP (B=0.17, [95% confidence intervals: 1.1-1.3], p=0.008 for systolic; and B=0.15, [95% confidence intervals: 1.0-1.3], p=0.02 for diastolic) independently predicted poorer cognitive performances.

CONCLUSIONS

In subjects with long-standing hypertension the blunted reduction of night-time BP is independently associated with lower cognitive performances.

Ablation for atrial fibrillation: are cures really achieved?

During the past 10 years numerous studies on the treatment of paroxysmal atrial fibrillation (AF) by right and left atrial ablation procedures have been published. The results of studies based on follow-up periods of a few months have been repeatedly interpreted as providing evidence for curative therapy. However, insufficient focus on the variability of the natural history of paroxysmal AF, the inadequate detection of silent arrhythmic events, the eclectic post-interventional use of antiarrhythmic drugs, and the lack of appropriate control groups make the reports unconvincing. Randomized controlled trials are needed to confirm postulated long-term cure rates for AF.

Non-valvular atrial fibrillation and stroke: Implications for nursing practice and therapeutics

Atrial fibrillation (AF) is the most common sustained cardiac rhythm disturbance and is increasing in prevalence due to the ageing of the population, and rates of chronic heart failure. Haemodynamic compromise and thromboembolic events are responsible for significant morbidity and mortality in Australian communities. Non-valvular AF is a significant predictor for both a higher incidence of stroke and increased mortality. Stroke affects approximately 40,000 Australians every year and is Australia's third largest killer after cancer and heart disease. The burden of illness associated with AF, the potential to decrease the risk of stroke and other embolic events by thromboprophylaxis and the implications of this strategy for nursing care and patient education, determine AF as a critical element of nursing practice and research. A review of the literature was undertaken of the CINAHL, Medline, EMBASE and Cochrane Databases from 1966 until September 2002 focussing on management of atrial fibrillation to prevent thrombotic events. This review article presents key elements of this literature review and the implications for nursing practice.

Medical comorbidity in black and white patients with Alzheimer's disease

BACKGROUND

Little is known about co-medical illnesses in black and white patients with probable Alzheimer's disease (AD).

METHODS

To address this question, we used two methods. In the first (Group I), black and white probable AD patients were matched on age at presentation to the clinic, age of onset of AD, duration of illness, and Mini-Mental State Examination scores; then, a variety of co-medical illnesses were compared between blacks and whites. In Group II, whites were randomly matched to blacks on the variables listed above.

RESULTS

In Group I, blacks were found to have a higher rate of hypertension than whites, whereas whites had a higher incidence of atrial fibrillation and cancer than blacks. In Group II, age at presentation to the clinic was found to be shorter for men than for women; duration of illness was shorter for black men than for white men, white women, and black women; and Mini-Mental State Examination scores were lower in blacks than whites. As in Group I, blacks were found to have a higher rate of hypertension, whereas whites had higher rates of atrial fibrillation, cancer, coronary artery disease, high cholesterol, and gastrointestinal disease.

CONCLUSION

In both groups, black patients with probable AD had a higher rate of hypertension than white patients with probable AD, and whites had higher rates of atrial fibrillation and cancer. This finding suggests that these comorbid illnesses in black and white patients with probable AD is not due to a statistical Type II error, but rather to differences in these groups.

Atrial fibrillation in the elderly: facts and management

Although atrial fibrillation is not widely known by the general public, in developed countries it is the most common arrhythmia. The incidence increases markedly with advancing age. Thus, with the growing proportion of elderly individuals, atrial fibrillation will come to represent a significant medical and socioeconomic problem. The consequences of atrial fibrillation have the greatest impact. The risk of thromboembolism is well known; other outcomes of atrial fibrillation are less well recognised, such as its relationship with dementia, depression and death. Such consequences are responsible for diminished quality of life and considerable economic cost. Atrial fibrillation is characterised by rapid and disorganised atrial activity, with a frequency between 300 and 600 beats/minute. The ventricles react irregularly, and may contract rapidly or slowly depending on the health of the conduction system. Clinical symptoms are varied, including palpitations, syncope, dizziness or embolic events. Atrial fibrillation may be paroxysmal, persistent or chronic, and a number of attacks are asymptomatic. Suspicion or confirmation of atrial fibrillation necessitates investigation and, as far as possible, appropriate treatment of underlying causes such as hypertension, diabetes mellitus, hypoxia, hyperthyroidism and congestive heart failure. In the evaluation of atrial fibrillation, cardiac exploration is invaluable, including electrocardiogram (ECG) and echocardiography, with the aim of detecting cardiac abnormalities and directing management. In elderly patients (arbitrarily defined as aged >75 years), the management of atrial fibrillation varies; it requires an individual approach, which largely depends on comorbid conditions, underlying cardiac disease, and patient and physician preferences. This management is essentially based on pharmacological treatment, but there are also nonpharmacological options. Two alternatives are possible: restoration and maintenance of sinus rhythm, or control of ventricular rate, leaving the atria in arrhythmia. Pharmacological options include antiarrhythmic drugs, such as class III agents, beta-blockers and class IC agents. These drugs have some adverse effects, and careful monitoring is necessary. The nonpharmacological approach to atrial fibrillation includes external or internal direct-current cardioversion and new methods, such as catheter ablation of specific foci, an evolving science that has been shown to be successful in a very select group of atrial fibrillation patients. Another serious challenge in the management of chronic atrial fibrillation in older individuals is the prevention of stroke, its primary outcome, by choosing an appropriate antithrombotic treatment (aspirin or warfarin). Several risk-stratification schemes have been validated and may be helpful to determine the best antithrombotic choice in individual patients.

Does advanced age affect the immediate and long-term results of direct-current external cardioversion of atrial fibrillation?

OBJECTIVES

To determine whether advanced age affects the immediate and long-term results of direct-current external cardioversion (ECV) of atrial fibrillation (AF), the sustained arrhythmia most commonly encountered in older patients.

DESIGN

Retrospective analysis of medical records.

SETTING

Intensive care unit.

PARTICIPANTS

Two hundred fifty consecutive patients(age 34-100) with AF who underwent ECV following a standardized protocol in an intensive care unit.

MEASUREMENTS

Immediate efficacy of ECV, defined as recovery of sinus rhythm, and maintenance of sinus rhythm over the follow-up were study outcomes. The univariate and multivariate associations of immediate efficacy of ECV and long-term results with clinical variables were analyzed.

RESULTS

At univariate analysis, immediate efficacy of ECV (overall, 91.2%) was lower in older patients and in those with chronic obstructive pulmonary disease, higher for a 3- to 90-day pre-ECV duration of AF than for a duration of 2 days or less or more than 90 days, and independent of underlying cardiac disease, hypertension, diabetes mellitus, previous AF, and left atrial dimension. However, pre-ECV duration of AF was the only multivariate predictor of ECV immediate success. Major complications occurred in only three patients. Of 220 patients discharged in sinus rhythm, 211 were followed up for a mean period +/- standard deviation of 34 +/- 25 months. AF relapsed in 45.5% of them. At multivariate analysis, underlying cardiac disease was the only predictor of the relapse rate, and relapse rate was lower in coronary heart disease than in valvular heart disease, congestive heart failure, or lone AF.

CONCLUSION

Immediate and long-term results of ECV of AF, an effective and safe procedure, are unaffected by age,at least after adjusting for several covariates.

Screening for cognitive impairment in the older adult

Screening for cognitive impairment in the older adult is an often overlooked element of health promotion. Health care providers may assume that existing deficits will be apparent on routine medical encounters. Frequently, however, patients who are functionally impaired can present a convincing facade of normalcy. Objective screening is necessary to recognize decline. This article briefly reviews normal age-related changes in cognition and suggested screening tools as well as differential diagnoses, highlighting reversible aspects of impairment. Additionally, potential corrective measures are considered where appropriate. This evaluation will become even more significant as the geriatric population steadily increases.

Heart disease and vascular risk factors in the cognitively impaired elderly: implications for Alzheimer's dementia

The term "cardiogenic dementia" was introduced a few decades ago to indicate an alteration of consciousness and cognition due to heart disease. Although this term is now disused, the relationship between cardiovascular disease and cognitive impairment is currently of great interest, not only for its potential therapeutic implications. but also for the recently recognized important role that vascular factors appear to play in Alzheimer's disease. The aims of this review are therefore 1) to show data supporting the role of cardiac disease--namely congestive heart failure, myocardial infarction and atrial fibrillation--and other vascular risk factors--i.e., hypertension and diabetes--in the development or worsening of cognitive impairment; 2) to highlight recent observations on the relationship between presence and severity of congestive heart failure/ myocardial infarction/atrial fibrillation and Alzheimer's disease: and 3) to uncover the type of studies needed in this field in order to facilitate a more precise algorithm of dementia prevention as well as intervention in demented patients with cardiovascular disease.