Rethinking Cognitive Health: The Atrial Fibrillation-Dementia Link

Significance 

Atrial Fibrillation (AF) is a common type of heart arrhythmia, characterized by an irregular and often rapid heart rate. It occurs when the two upper chambers of the heart (the atria) beat chaotically and out of sync with the two lower chambers (the ventricles). This can lead to a variety of symptoms, including heart palpitations, shortness of breath, weakness, and reduced ability to exercise. There is growing evidence suggesting a link between Atrial Fibrillation and an increased risk of developing dementia.  It is believed AF can lead to an inconsistent blood flow to the brain. Regular heart rhythms help to ensure a consistent blood supply, but the erratic heartbeats in AF can disrupt this, potentially leading to reduced blood flow to the brain. Moreover, AF significantly increases the risk of stroke. When the heart doesn’t beat properly, blood can pool and form clots in the atria. If a blood clot forms, it can travel to the brain, leading to a stroke. Strokes can cause brain damage, which is a risk factor for certain types of dementia. Additionally, AF may contribute to cerebral small vessel disease, a condition in which the small arteries in the brain are damaged. This damage can also contribute to the development of dementia. It is also believed that AF can lead to chronic inflammation in the body, which has been linked to the development of dementia. Inflammation can damage brain cells and contribute to the decline in cognitive functions. It is noteworthy to mention that both AF and dementia share common risk factors such as high blood pressure, diabetes, and age. These overlapping risk factors can contribute to the development of both conditions.

In a new study published in the Journal of the American College of Cardiology by Sheng-Chia Chung PhD, Martin Rossor MD, Ana Torralbo PhD, Cai Ytsma MSc, Natalie K. Fitzpatrick MSc, Spiros Denaxas PhD, and led by Professor Rui Providencia MD, PhD from the University College London investigated the association between atrial fibrillation (AF) and the development of mild cognitive impairment (MCI), along with its progression to dementia. The study spanned from January 1, 1998, to May 31, 2016. The researchers included all individuals with incident AF and defined the index date as the date of the first recorded AF diagnosis. For each case of AF, a control individual without AF was randomly selected from the study cohort. These controls were matched to the cases based on sex and age at the diagnosis of AF. AF was identified using ICD-10 codes and corresponding Read version 2 terms from the Clinical Practice Research Datalink.

A key aspect of the study was the use of the UK-based linked electronic health records (EHR), which provided a rich source of data for analysis. The researchers defined AF based on ICD-10 codes and included a comprehensive set of variables such as socio-demographic factors, comorbidities, and treatments like digoxin and oral anticoagulants. This holistic approach allowed for a nuanced understanding of the AF-MCI-dementia trajectory.

The study’s findings are profound. Firstly, it established that AF is associated with a 45% increased risk of developing MCI. This is a significant leap in understanding the cognitive risks associated with AF, a common cardiac arrhythmia. Moreover, the study showed that cardiovascular risk factors and multimorbidity are linked to this increased risk, providing insights into potential intervention points. The implications of these findings are far-reaching. For clinicians, it underscores the importance of vigilant cognitive health monitoring in AF patients. It also suggests that managing cardiovascular risk factors and multimorbidity could be key in preventing or delaying cognitive decline in this population. Furthermore, the study challenges existing paradigms about the relationship between heart health and brain health. It positions AF not just as a cardiac issue but also a potential contributor to cognitive impairment and dementia. This reframing is crucial for developing integrated care approaches that address both cardiac and cognitive health. The significance of the study also lies in its methodological robustness. The large-scale population-based approach, coupled with the detailed analysis of EHR data, lends a high degree of reliability and applicability to the findings. It sets a new standard for epidemiological studies in the field of cognitive health.

In summary, this study is a seminal work in the intersection of cardiology and neurology. It not only elucidates the link between atrial fibrillation and cognitive decline but also prompts a reevaluation of clinical approaches towards AF patients. Management of AF, particularly through anticoagulants to prevent stroke, and controlling other risk factors like hypertension and diabetes, is crucial in potentially reducing the risk of developing dementia. It’s important for patients with AF to work closely with their healthcare providers to manage their condition and reduce their risk of associated complications, including dementia. The study’s revelations about the role of cardiovascular health in cognitive outcomes pave the way for more integrated and proactive strategies in managing patients with atrial fibrillation, with the ultimate goal of preserving cognitive function and quality of life.

Rethinking Cognitive Health: The Atrial Fibrillation-Dementia Link - Medicine Innovates
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About the author

Prof Rui Bebiano Da Providencia E Costa

Professor of Cardiovascular Epidemiology & Evidence Synthesis
Faculty of Pop Health Sciences
Institute of Health informatics Research, University College London

My involvement in Research started simultaneously with my Cardiology training, and I have combined both activities uninterruptedly ever since. After an initial period performing basic science, I chose to focus on clinical science, and later epidemiology and genetics. I have authored over 200publications in the field of cardiology and arrhythmias, some of which have been included in international guidelines – British, European and American -for the management of cardiovascular disease. My main research interests areatrial fibrillation, sudden cardiac death, catheter ablation techniques/approaches, clinical epidemiology and genetics. In 2015, I was awarded with the Young Investigator Award in Clinical Science at the European Heart Rhythm Association Congress, in Milan. The investigation was on there producibly of cryoballoon ablation vs. radio frequency ablation for the treatment of atrial fibrillation in a multic entre French survey. Those were data from the early days of this technique which has now become mainstream andhas gained worldwide usage. In 2016 I started working with Professor JP Casas at the Institute of Health Informatics with the aim of creating a group specialising on the epidemiology of arrhythmic disorders. I am currently studying the natural history of AF in the UK in a database of 6.7 million patients, and identifying the different AF sub-phenotypes based on the concept of clinical trajectories. One of my recent interests is the identification of novel drug targets for atrial fibrillation. I have been the Coordinating Editor of Cochrane’s Heart Group since 2018 and have an interest in evidence synthesis – I am currently collaborating in the preparation of 7 systematic reviews for the new Guideline in the treatment and prevention of acute rheumatic fever and rheumatic heart disease.

Reference

Sheng-Chia Chung, Martin Rossor, Ana Torralbo, Cai Ytsma, Natalie K. Fitzpatrick, Spiros Denaxas, Rui Providencia, Cognitive Impairment and Dementia in Atrial Fibrillation: A Population Study of 4.3 Million Individuals, JACC: Advances, Volume 2, Issue 9, 2023, 100655,

Go To JACC: Advances