Atrial fibrillation in stroke-free patients is associated with memory impairment and hippocampal atrophy

Outcome of Patients Discharged after their First Detected Episode of Atrial Fibrillation

Atrial fibrillation (AF) is the most frequent supraventricular arrhythmia with an approximative prevalence of 1 % in the general population and above 6 % in the elderly. After a first AF diagnosis, the hospitalization rate is markedly increased. Management of a first AF episode is different depending on the clinical status of patients. Practical guidelines developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society are available for the management of these patients. A four-step decisional scheme must be followed in the management of a first recent AF episode: need for a short- and long-term anticoagulation, define a rythmologic strategy (rhythm or rate control), select the weapon (drug, device or ablation) and reconsider the strategy if needed. After a first uncomplicated paroxysmal AF episode, guidelines recommend that prescription of antiarrhythmics must be avoided and anticoagulation is optional. After a first persistent AF episode, guidelines recommend to either respect or reduce the arrhythmia. Prescription of antiarrhythmics and anticoagulation is also optional depending on the patient?s condition. In case of the AF reduction decision, anticoagulation must be tailored preliminary to this reduction. AF recurrence rate varies depending on the patient?s condition, and the risk of stroke assessed by the CHA₂DS₂-VASc score might be similarly considered for both paroxysmal and persistent AF.

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.

[Management and therapy of atrial fibrillation in geriatric patients]

Among geriatric patients, atrial fibrillation is the most common cardiac arrhythmia. In patients over 80 years of age, the prevalence rises to approximately 10%. Atrial fibrillation is associated with serious health implications, including a 2-fold increase in mortality risk and a 5-fold increase in stroke risk. In contrast to these facts, the current guidelines on the management of atrial fibrillation of the European Society of Cardiology (ESC) contain only a short paragraph on these patients. Many relevant clinical aspects go without any comment. Thus, the purpose of our paper is to discuss those special needs of geriatric patients and their physicians which are not mentioned in the guidelines of the ESC. In our review, we discuss rhythm versus rate control, oral anticoagulation, outcome, prevention, falls, adherence, polypharmacy, dementia, nursing home patients, frailty, and geriatric assessment in consideration of geriatric patients. An extended search of the literature on Pubmed served as the basis for this review. Individual aspects of each geriatric patient should be considered when managing these complex patients; however, the complexity of each case must not lead to an individualized therapy that is not in accordance with current guidelines and the literature. A large number of papers which help us to answer most of the clinical questions regarding the management of trial fibrillation in geriatric patients have already been published.

One-year cholesterol lowering treatment reduces medial temporal lobe atrophy and memory decline in stroke-free elderly with atrial fibrillation: evidence from a parallel group randomized trial

OBJECTIVES

In elderly patients with atrial fibrillation (AF), medial temporal lobe (MTL) atrophy and white matter lesions (WML) may account for the cognitive decline. Though a combination therapy of statins with cholesterol lowering agents like ezetimibe may be beneficial in patients with AF, its effects on MTL structure and WML remains unknown.

METHODS

A parallel group double-blinded randomized trial was performed during 1 year whereby elderly stroke-free AF patients either received placebo or atorvastatin and ezetimibe on top oral anticoagulation therapy. Neuropsychological performance and inflammatory markers in the blood were assessed at baseline and 1 year later together with amygdala and hippocampal volume as well as WML.

RESULTS

Sixty-three patients were assessed for eligibility, but 29 patients had to be excluded so that 34 patients were randomized to both groups. In the treatment group, the systemic level of inflammation was significantly decreased after 1 year and an improvement in cognitive speed as well as short- and long-term memory was observed. While there was no significant difference in MTL volume at baseline, the placebo group exhibited more atrophy for right amygdala and left hippocampus at follow-up. Finally, descriptive data showed a slight decline of WML volume in the treatment group.

CONCLUSIONS

In spite of limitations due to small sample size, our data suggest that intensive cholesterol lowering therapy in AF patients may slow cognitive decline and atrophy of the MTL. Though these results have to be replicated in a larger sample, they offer potential for future interventions.

Left Atrial Catheter Ablation and Ischemic Stroke

Left atrial catheter ablation (LACA) has become an established therapy to abolish drug-refractory symptomatic paroxysmal and persistent atrial fibrillation. Restoring sinus rhythm by LACA may help to prevent atrial fibrillation-related strokes, but presently there is no evidence from randomized clinical trials to support this notion. This review summarizes the current knowledge and uncertainties regarding LACA and procedure-related ischemic stroke. In fact, most patients who undergo LACA have a rather low annual stroke risk even when left untreated, whereas LACA imposes a risk of procedure-related stroke of ≈0.5% to 1%. In addition, LACA may cause cerebral microemboli, resulting in ischemic lesions. These cerebral lesions, detectable by high-resolution MRI, could contribute to neuropsychological deficits and cognitive dysfunction. Furthermore, recurrent atrial fibrillaton episodes can be detected up to years after LACA and might cause ischemic strokes, especially in those patients in whom therapeutic anticoagulation was discontinued. Further prospective multicenter trials are needed to identify procedure-dependent risk factors for stroke and to optimize postprocedural anticoagulation management.

Dementia, Stroke, and Vascular Risk Factors; a Review

Interest in dementia has increased over the past few decades. Stroke is an important cause of cognitive problems. The term vascular cognitive impairment is now used to describe dementia attributed to stroke or deep white matter lesions detected on imaging. Although vascular cognitive impairment is increasingly diagnosed, Alzheimer's disease remains the most common dementia worldwide. The relationship between Alzheimer's disease and vascular cognitive impairment is unclear, although there exists significant overlap, which prompts physicians to consider them opposite ends of a disease spectrum, rather than separate entities. There is also substantial evidence that stroke risk factors such as hypertension, diabetes; lipid disorders, etc. are independently associated with an increased risk of Alzheimer's disease and vascular cognitive impairment. Evidence suggests that these risk factors have a cumulative effect on Alzheimer's disease development but not on vascular cognitive impairment. This is more marked in Alzheimer's disease patients in the presence of the ε4 allelic variant of apolipoprotein E. How these risk factors increase the risk of dementia is largely unknown. Physicians must be aware that stroke causes dementia; that vascular risk factors appear to be independent risk factors in developing dementia, and that poststroke care must include cognitive assessment.

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.

Atrial fibrillation (AF) and cognitive impairment in the elderly: a case-control study

AF is able not only to increase the risk of cognitive decline due to acute cerebrovascular events, but also to reduce cardiac output, with the consequence of impaired cerebral perfusion. The aim of this study was to evaluate the association between AF, dementia and depression in patients with negative anamnesis for past strokes. Our sample included 26 patients with a diagnosis of AF (paroxystic, persistent, permanent) and 31 patients with sinus rhythm, enrolled as controls. All selected patients underwent a Multidimensional Geriatric Assessment in order to investigate cognitive and behavioral functions. Statistical analysis of results showed a greater frequency of latent cognitive impairment in patients with AF, even in the absence of memory disorders. As a matter of facts, AF patients showed Mini Mental State Examination (MMSE) scores significantly lower than those with sinus rhythm (p<0.05) and Geriatric Depression Scale (GDS) scores higher than those without AF, evidencing a greater risk of depression too (p<0.02). Results showed a statistically significant association between AF, depression and cognitive impairment in early stage. In conclusion, AF is not only associated with the risk of developing cognitive impairment, but it can also be considered as a risk factor for dementia and depression, even in the absence of medical history of past stroke.

[Epidemiology, clinical picture and management of atrial fibrillation]

Atrial fibrillation (AF) is the most common cardiac arrhythmia, affects approximately 1% of adults and prevalence increases with age. Nine per cent of those aged 80 years and older have AF. AF is associated with increased cardiovascular mortality and morbidity, including stroke.Stroke in patients with AF is more severe and more likely to be fatal. Prevention of thromboembolism with oral anticoagulants and rate or rhythm control are the main therapeutic strategies for patients with AF. Vitamin K antagonists reduce the risk of stroke in patients with AF, however are underutilized. Dronedarone is the first antiarrhythmic drug that reduces the stroke rate.

The hidden-Markov brain: comparison and inference of white matter hyperintensities on magnetic resonance imaging (MRI)

Rating and quantification of cerebral white matter hyperintensities on magnetic resonance imaging (MRI) are important tasks in various clinical and scientific settings. As manual evaluation is time consuming and imprecise, much effort has been made to automate the quantification of white matter hyperintensities. There is rarely any report that attempts to study the similarity/dissimilarity of white matter hyperintensity patterns that have different sizes, shapes and spatial localizations on the MRI. This paper proposes an original computational neuroscience framework for such a conceptual study with a standpoint that the prior knowledge about white matter hyperintensities can be accumulated and utilized to enable a reliable inference of the rating of a new white matter hyperintensity observation. This computational approach for rating inference of white matter hyperintensities, which appears to be the first study, can be utilized as a computerized rating-assisting tool and can be very economical for diagnostic evaluation of brain tissue lesions.

Vascular diseases and old age mental disorders: an update of neuroimaging findings

PURPOSE OF REVIEW

To review neuroimaging findings that have been reported in samples of patients with cardiovascular disorders and their association with the onset of Alzheimer's disease, vascular dementia, depression and bipolar disorder in the elderly and to highlight the implications of these findings to the knowledge about the pathophysiology of psychiatric disorders in old age, as well as their potential clinical implications.

RECENT FINDINGS

Vascular risk factors, such as hypertension, diabetes, dyslipidemia, smoking habits and heart failure, have all been associated with signs of cerebrovascular dysfunction, including structural MRI findings of signal hyperintensities, lacunes and stroke and functional imaging findings of brain regional hypoperfusion and hypometabolism. Such brain abnormalities have been found to increase the risk of onset of psychiatric disorder (depression, bipolar and dementia) in old age.

SUMMARY

As vascular risk factors are potentially modifiable when detected in midlife, the early characterization of brain changes associated with the presence of cardiovascular diseases holds promise to afford clinical applications in psychiatry, providing new perspectives for the prevention of old age psychiatric disorders.

Radiofrequency Catheter Ablation of Atrial Fibrillation: A Cause of Silent Thromboembolism?

Background—

Radiofrequency left atrial catheter ablation has become a routine procedure for treatment of atrial fibrillation. The aim of this study was to assess with preprocedural and postprocedural cerebral magnetic resonance imaging the thromboembolic risk, either silent or clinically manifest, in the context of atrial fibrillation ablation. The secondary end point was the identification of clinical or procedural parameters that correlate with cerebral embolism.

Methods and Results—

A total of 232 consecutive patients with paroxysmal or persistent atrial fibrillation who were candidates for radiofrequency left atrial catheter ablation were included in the study. Pulmonary vein isolation or pulmonary vein isolation plus linear lesions plus atrial defragmentation with the use of irrigated-tip ablation catheters was performed. All of the patients underwent preprocedural and postablation cerebral magnetic resonance imaging. A periprocedural symptomatic cerebrovascular accident occurred in 1 patient (0.4). Postprocedural cerebral magnetic resonance imaging was positive for new embolic lesions in 33 patients (14). No clinical parameters such as age, hypertension, diabetes mellitus, previous history of stroke, type of atrial fibrillation, and preablation antithrombotic treatment showed significant correlation with ischemic cerebral embolism. Procedural parameters such as activated clotting time value and, in particular, electric or pharmacological cardioversion to sinus rhythm correlated with an increased incidence of cerebral embolism. Cardioversion was also associated with an increased risk of 2.75 (95 confidence interval, 1.29 to 5.89; P =0.009).

Conclusions—

Radiofrequency left atrial catheter ablation carries a low risk of symptomatic cerebral ischemia but is associated with a substantial risk of silent cerebral ischemia detected on magnetic resonance imaging. Independent risk factors for cerebral thromboembolism are the level of activated clotting time and, in particular, the electric or pharmacological cardioversion to sinus rhythm during the procedure.

Automated detection of white matter changes in elderly people using fuzzy, geostatistical, and information combining models

Detection of white matter changes of the brain using magnetic resonance imaging (MRI) has increasingly been an active and challenging research area in computational neuroscience. There have rarely been any single image analysis methods that can effectively address the issue of automated quantification of neuroimages, which are subject to different interests of various medical hypotheses. This paper presents new image segmentation models for automated detection of white matter changes of the brain in an elderly population. The methods are based on the computational models of fuzzy clustering, possibilistic clustering, geostatistics, and knowledge combination. Experimental results on MRI data have shown that the proposed image analysis methodology can be applied as a very useful computerized tool for the validation of our particular medical question, where white matter changes of the brain are thought to be the most important social medical evidence.

The impact of new and emerging clinical data on treatment strategies for atrial fibrillation

INTRODUCTION

The Atrial Fibrillation (AF) Exchange Group, an international multidisciplinary group concerned with the management of AF, was convened to review recent advances in the field and the potential impact on treatment strategies.

METHODS

Issues discussed included epidemiology and the impact of the rising incidence of AF on health care systems, developments in pharmacological and surgical interventions in the management of arrhythmias and thromboprophylaxis, the potential to affect treatment strategies, and barriers to implementing them.

RESULTS

The incidence of AF and the associated burden on health care systems are increasing with aging populations, prevalence of comorbidities and more effective treatment of cardiovascular diseases. Advances in available medical treatments, in particular dronedarone and dabigatran, with other products in development, offer the possibility of changes in treatment paradigms and a greater emphasis on reducing hospitalizations and improvement in long-term outcomes instead of a symptom/safety-driven approach in which the priority is symptom suppression without provoking drug toxicity. Developments in catheter ablation techniques may mean that, in experienced centers, ablation may be offered as first-line treatment in selected patient populations. Barriers to optimal treatment include underdiagnosis, lack of recognition as a serious condition and as a risk factor for stroke, limited access to care, inadequate implementation of guidelines, and poor adherence to treatment.

CONCLUSIONS

The focus of the management of AF may be changing as a consequence of new treatments based on the outcome improvements they offer. However, the benefits will not be fully realized if guidelines and guidance are not observed in routine clinical practice.

Atrial fibrillation is independently associated with senile, vascular, and Alzheimer's dementia

BACKGROUND

The aging population has resulted in more patients living with cardiovascular disease, such as atrial fibrillation (AF). Recent focus has been placed on understanding the long-term consequences of chronic cardiovascular disease, such as a potential increased risk of dementia.

OBJECTIVE

This study sought to determine whether there is an association between AF and dementia and whether their coexistence is an independent marker of risk.

METHODS

A total of 37,025 consecutive patients from the large ongoing prospective Intermountain Heart Collaborative Study database were evaluated and followed up for a mean of 5 years for the development of AF and dementia. Dementia was sub-typed into vascular (VD), senile (SD), Alzheimer's (AD), and nonspecified (ND).

RESULTS

Of the 37,025 patients with a mean age of 60.6 +/- 17.9 years, 10,161 (27%) developed AF and 1,535 (4.1%) developed dementia (179 VD, 321 SD, 347 AD, 688 ND) during the 5-year follow-up. Patients with dementia were older and had higher rates of hypertension, coronary artery disease, renal failure, heart failure, and prior strokes. In age-based analysis, AF independently was significantly associated with all dementia types. The highest risk was in the younger group (<70). After dementia diagnosis, the presence of AF was associated with a marked increased risk of mortality (VD: hazard ratio [HR] = 1.38, P = .01; SD: HR = 1.41, P = .001; AD: HR = 1.45; ND: HR = 1.38, P <.0001).

CONCLUSION

AF was independently associated with all forms of dementia. Although dementia is strongly associated with aging, the highest risk of AD was in the younger group, in support of the observed association. The presence of AF also identified dementia patients at high risk of death.

Changing perspectives regarding late-life dementia

Individuals over 80 years of age represent the most rapidly growing segment of the population, and late-life dementia has become a major public health concern worldwide. Development of effective preventive and treatment strategies for late-life dementia relies on a deep understanding of all the processes involved. In the centuries since the Greek philosopher Pythagoras described the inevitable loss of higher cognitive functions with advanced age, various theories regarding the potential culprits have dominated the field, ranging from demonic possession, through 'hardening of blood vessels', to Alzheimer disease (AD). Recent studies suggest that atrophy in the cortex and hippocampus-now considered to be the best determinant of cognitive decline with aging-results from a combination of AD pathology, inflammation, Lewy bodies, and vascular lesions. A specific constellation of genetic and environmental factors (including apolipoprotein E genotype, obesity, diabetes, hypertension, head trauma, systemic illnesses, and obstructive sleep apnea) contributes to late-life brain atrophy and dementia in each individual. Only a small percentage of people beyond the age of 80 years have 'pure AD' or 'pure vascular dementia'. These concepts, formulated as the dynamic polygon hypothesis, have major implications for clinical trials, as any given drug might not be ideal for all elderly people with dementia.

[Does every case of atrial fibrillation need to be treated?]

There is a risk of atrial fibrillation for 1 in 4 adults over the age of 40 years. In most cases the cause of atrial fibrillation is an underlying organic disease. Approximately 2.5 million mostly elderly male patients in Europe are affected by this dysrhythmia and it is expected that the number of patients will more than double by the year 2050. With a few exceptions every form of fibrillation should be treated regarding the underlying disease, the risk of thrombo-embolization and the arrhythmogenic symptoms. However, it must be questioned whether every case of atrial fibrillation must be anti-arrhythmically treated or in which cases rate control of ventricle function is adequate or whether rhythm control, i.e. conversion into sinus rhythm, is necessary. Arguments for conversion into a sinus rhythm are improved cardiac output, decreased risk of thrombo-embolization and hypercoagulability as well as a reduction of tachycardiomyopathies. A decline in clinical symptoms leads to improvement in the quality of life and also in many cases brain function.

The patient with atrial fibrillation

Atrial fibrillation is a frequently encountered arrhythmia, particularly affecting the elderly. Patients at significant risk for stroke should be considered for anticoagulation with warfarin. Management of atrial fibrillation revolves around either controlling the ventricular rate response or trying to maintain sinus rhythm with either pharmacologic or nonpharmacologic therapies. There are many treatment options to consider, based upon the patient's expectations, symptoms, and comorbid conditions. Therefore, the treatment of atrial fibrillation must be individualized.