We searched Medline between January, 2000, and September, 2011, with the following terms individually or in combination: “atrial fibrillation”, “rate control”, “rhythm control”, “antithrombotic therapy”, “anticoagulation”, “stroke risk”, “bleeding risk”, “antiplatelet therapy”, “vernakalant”, and “dronedarone”. Additionally, we studied abstracts from national and international cardiovascular meetings to identify unpublished studies. The extensive detailed published work for the underlying
SeminarAtrial fibrillation
Introduction
Atrial fibrillation is the most common sustained cardiac rhythm disorder, and is increasing in prevalence and incidence.1 It is recognised as an increasing health-care burden, because of an ageing population and improved survival from disorders such as acute myocardial infarction. The lifetime risk for development of atrial fibrillation is about one in four for men and women aged 40 years and older, whereas for those without previous or concurrent congestive heart failure or myocardial infarction the lifetime risk is still about 16%.2, 3 The presence of atrial fibrillation independently increases the risk of mortality and morbidity due to stroke and thromboembolism, congestive heart failure, and impaired quality of life, resulting in a high health-care cost and public health burden.4, 5
In this Seminar, we review the epidemiology and pathophysiology of atrial fibrillation, and specifically address areas in which management of the disorder has advanced or developed since previous overviews on this topic.5, 6
Section snippets
Epidemiology
In the UK, findings from the Screening for Atrial Fibrillation in the Elderly (SAFE) study7 showed a baseline prevalence of atrial fibrillation of 7·2% in patients aged 65 years and older, with an increased prevalence in men (7·8%) and in those aged 75 years and older (10·3%), and a yearly incidence of new atrial fibrillation of about 1·6%. Investigators of one community survey reported a rise in incidence of atrial fibrillation of 12·6% during the past two decades, and projected that 15·9
Risk factors
Atrial fibrillation commonly coexists with cardiovascular risk factors and disorders, which in turn increase the risk of complications associated with the arrhythmia. Common predisposing factors for atrial fibrillation include both non-cardiovascular (eg, chest disease, infection) and cardiovascular (eg, hypertension, congestive heart failure, valvular heart disease, diabetes mellitus, and vascular disease) risk factors. Data from the Atherosclerosis Risk in Communities (ARIC) study11 have
Initial diagnostic considerations
For an assessment of a patient with atrial fibrillation, confirmation of the diagnosis and documentation of the arrhythmia are needed. Guidelines from the European Society of Cardiology (ESC) define atrial fibrillation as a cardiac arrhythmia with the following characteristics: the surface ECG shows absolutely irregular RR intervals; there are no distinct P waves on the surface ECG; and the atrial cycle length (ie, the interval between two atrial activations), when visible, is usually variable
Management
Management of atrial fibrillation needs early identification and treatment of predisposing factors and concomitant disorders, with the use of upstream therapy (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, statins, and omega-3 polyunsaturated fatty acids) when appropriate.4 After assessment of thromboembolic risk and appropriate thromboprophylaxis, rate or rhythm control strategies should be considered (figure 1).4
Subdivision into clinical subtypes of atrial
Stroke prevention
A prothrombotic state has been described in atrial fibrillation, and it contributes to the most common (and most important) complication of thromboembolism.30 The presence of atrial fibrillation is an independent risk factor for stroke and thromboembolism, and stroke in association with atrial fibrillation increases mortality and morbidity, with greater disability, longer hospital stays, and lower rates of discharge to patients' own homes.31 Although atrial fibrillation increases the risk of
Thromboprophylaxis in atrial fibrillation
In one study,49 adjusted dose warfarin reduced stroke risk by 64% (95% CI 49–74) and, importantly, all-cause mortality by 26% (3–43) compared with placebo. In a cohort of Medicare patients, the use of warfarin increased between 1992 and 2002, which greatly reduced the incidence of ischaemic stroke over that decade but not the rate of haemorrhagic strokes.60 By contrast, the value of aspirin in atrial fibrillation has been debated. In Hart and colleagues' meta-analysis,49 antiplatelet therapy
Initial management of atrial fibrillation
In patients presenting with newly diagnosed atrial fibrillation, the short-term treatment goal should be control of their symptoms with rate or rhythm control therapies.4, 5, 6 Except for the need of emergency cardioversion to restore sinus rhythm in patients with haemodynamic instability due to very rapid ventricular rates or presence of structural heart disease, the initial therapeutic approach should include assessment for the underlying causes of atrial fibrillation and ventricular rate
Cardiac pacing
In patients with atrial fibrillation who do not respond or are intolerant to atrioventricular blocking agents for ventricular rate control, atrioventricular nodal ablation with permanent pacemaker implant improves symptoms and quality of life.110, 111 After atrioventricular nodal ablation, biventricular pacing might be preferable to right ventricular pacing, especially in patients with impaired LVEF, to prevent deterioration of cardiac function.112, 113 However, cardiac resynchronisaton therapy
Conclusions
The management of atrial fibrillation has had substantial new developments. The limitations of aspirin (including its potential for bleeding, especially in elderly people) and the availability of new oral anticoagulant drugs that overcome the inherent drawbacks associated with warfarin would allow more widespread use of oral anticoagulant drugs, which would improve stroke prevention in atrial fibrillation. Stroke risk stratification, with comprehensive risk factor assessment, has led to a shift
Search strategy and selection criteria
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