Atrial fibrillation

Atrial fibrillation
J. Heuser · CC BY-SA 3.0 · source
Name	Atrial fibrillation
Caption	Electrocardiogram tracing showing irregular rhythm
Field	Cardiology
Symptoms	Palpitations, dyspnea, fatigue, syncope
Complications	Stroke, heart failure, thromboembolism
Onset	Sudden or gradual
Duration	Paroxysmal, persistent, permanent
Frequency	Common
Treatment	Rate control, rhythm control, anticoagulation, ablation

Atrial fibrillation Atrial fibrillation is a common cardiac arrhythmia characterized by disorganized atrial electrical activity leading to irregular ventricular response. It presents across a spectrum from intermittent episodes to chronic persistent forms and is a major cause of morbidity due to thromboembolic stroke and heart failure. Management integrates clinical assessment, imaging, pharmacotherapy, and procedural interventions to reduce symptoms and prevent complications.

Signs and symptoms

Patients frequently report palpitations, reduced exercise tolerance, dyspnea and episodes of dizziness or syncope; less specific complaints include fatigue and chest discomfort. Typical presentations can be acute with rapid ventricular rates prompting emergency evaluation or chronic with progressive exertional limitation seen in clinics associated with specialists at Mayo Clinic, Cleveland Clinic, Johns Hopkins Hospital, Massachusetts General Hospital and Mount Sinai Health System. On examination, findings often include an irregularly irregular pulse and variable intensity of the first heart sound noted in texts from Oxford University Press, Elsevier, Springer Nature and curricula at Harvard Medical School, Stanford University School of Medicine, University of Oxford.

Causes and risk factors

Etiologies include structural heart disease such as valvular lesions after rheumatic fever described in historical series from John Snow-era epidemiology, ischemic heart disease post–myocardial infarction summarized in guidelines from European Society of Cardiology and American Heart Association, and cardiomyopathies referenced in monographs by American College of Cardiology. Noncardiac contributors include hyperthyroidism long studied at Karolinska Institutet, alcohol use disorders discussed in reports by World Health Organization, and pulmonary disease encountered in cohorts at National Institutes of Health. Demographic and genetic predispositions have been linked to loci investigated by consortia including Wellcome Trust and efforts at Broad Institute; clinical risk scores draw on datasets from Framingham Heart Study and population studies like UK Biobank.

Pathophysiology

The arrhythmia arises from triggered activity and reentrant circuits in atrial myocardium, often involving pulmonary vein ostia as demonstrated in seminal electrophysiology work at University of California, Los Angeles and Guy's and St Thomas' NHS Foundation Trust. Structural remodeling with fibrosis and dilation, profiled in imaging cohorts from Mayo Clinic and histopathology collections at Massachusetts General Hospital, alters conduction and refractory periods. Neurohormonal influences mediated by autonomic tone, catecholamines studied in laboratories at National Institute of Mental Health and inflammatory pathways explored at National Heart, Lung, and Blood Institute contribute to initiation and perpetuation. Cellular mechanisms of ion channel dysfunction have been elucidated in basic science research at Cold Spring Harbor Laboratory, Salk Institute, and Max Planck Institute.

Diagnosis

Diagnosis is based on electrocardiographic demonstration of irregularly irregular RR intervals and absent distinct P waves, a criterion found in guidelines from European Society of Cardiology, American Heart Association, and textbooks by Guyton and Hall. Ambulatory monitoring with Holter devices and implantable loop recorders used in trials at Cleveland Clinic and University of California, San Francisco quantify burden. Echocardiography provided by departments at Johns Hopkins Hospital and Mount Sinai Health System assesses atrial size and valvular disease. Advanced modalities such as cardiac MRI and CT employed in centers like Mayo Clinic and Massachusetts General Hospital evaluate structural substrates and pulmonary vein anatomy for procedural planning.

Management and treatment

Therapeutic strategies encompass rate control, rhythm control, and stroke prevention, as codified by consensus documents from European Society of Cardiology and American College of Cardiology. Rate control often uses beta-blockers and calcium channel blockers available in formularies at National Health Service trusts and hospitals affiliated with Columbia University Irving Medical Center. Rhythm control includes antiarrhythmic drugs described in pharmacology texts at Oxford University Press and catheter ablation pioneered in randomized trials at Cleveland Clinic and St Bartholomew's Hospital. Anticoagulation for thromboembolic risk uses vitamin K antagonists or direct oral anticoagulants evaluated in multicenter trials coordinated by organizations such as World Health Organization and National Institutes of Health. Device therapies, including pacemakers and left atrial appendage occlusion, have been developed and tested at institutions including Mayo Clinic, Massachusetts General Hospital, and Johns Hopkins Hospital.

Complications and prognosis

Major complications include ischemic stroke, systemic embolism, and heart failure; stroke prevention efforts are informed by large trials from networks like European Medicines Agency and Food and Drug Administration. Mortality and morbidity relate to underlying comorbidity profiles characterized in cohorts such as the Framingham Heart Study and registries maintained by American Heart Association. Prognosis varies with age, comorbidity, and treatment; quality-of-life outcomes have been evaluated in comparative effectiveness studies from Institute for Clinical and Economic Review and health services research at Kaiser Permanente.

Epidemiology and public health impact

Prevalence rises with age and demographic shifts documented in epidemiologic reports from World Health Organization, Global Burden of Disease study coordinated by Institute for Health Metrics and Evaluation, and national surveillance by Centers for Disease Control and Prevention. Health system burdens including hospital admissions and costs are analyzed by agencies such as Agency for Healthcare Research and Quality and payers like Medicare. Public health strategies emphasize screening and risk-factor modification promoted by professional societies including European Society of Cardiology and American Heart Association to mitigate the growing clinical and economic impact.

Category:Cardiology