Asymptomatic Atrial Fibrillation
Section snippets
Symptoms
Patients with AF commonly experience palpitations, dyspnea, chest pain, light-headedness, and fatigue. The precise mechanism by which AF causes symptoms is poorly understood. The hemodynamic consequences of (1) loss of atrial contraction and, thus, loss of atrioventricular (AV) synchrony; (2) heart rate (HR) irregularity; and (3) rapid ventricular response in AF may each contribute in varying degrees to the manifestation of symptoms. Loss of atrial contractility and its contribution to
Epidemiology of Asymptomatic AF
The reported incidence of asymptomatic AF depends on the frequency of monitoring, duration of follow-up, and the burden of AF in the population studied. In a study by Camm et al, among 106 asymptomatic elderly patients (≥75 years old), the incidence of AF detected by a “scout” 24-hour ambulatory monitor was 10.5%.11 Psaty et al reported 304 new cases of AF in 4844 patients aged 65 years or older screened with annual ECGs, history and physical examination, or hospital discharge diagnoses.
Asymptomatic AF in Patients With Implantable Monitoring Devices and Indications for a Permanent Pacemaker
Another high-risk population for AF is patients with sinus node dysfunction or AV conduction abnormalities. The reported incidence of AF in this population of patients may be as high as 4% to 6% per year.16 Many of these patients require a permanent pacemaker or, rarely, an atrial defibrillator, which then provides the opportunity to continuously monitor for atrial arrhythmias. In a study of patients with a clinical history of symptomatic AF by Defaye et al, a diagnostic algorithm for
Reliability of Symptoms
The study by Israel et al illustrates the poor correlation between symptoms and AF. During the study, 40% of patients reported symptoms suggestive of AF, but device interrogation proved absence of AF during the respective episodes.17 Symptoms cannot be relied upon, even in patients who initially present with symptomatic AF. In one study, it was shown that asymptomatic AF occurred 12 times more frequently than symptomatic AF.9 The poor correlation between symptoms and AF demonstrated in these
The Role of Drugs in Asymptomatic Bouts of AF
The presence of asymptomatic AF in patients treated with antiarrhythmic drugs is well recognized; however, the interaction of pharmacological interventions on the manifestation of symptoms has not been systematically studied. Antiarrhythmic agents could potentially alleviate symptoms by shortening the duration of arrhythmia, smoothing the ventricular rhythm (making it less irregular), or by slowing the ventricular response. Certain AV nodal drugs, including digoxin, β-adrenergic receptors
Clinical Consequences of Silent AF
The prevalence of asymptomatic AF has significant clinical implications:
- 1.
The magnitude of the problem reported in epidemiological studies of AF significantly underestimates the burden of arrhythmia on society because asymptomatic arrhythmias are not included.
- 2.
Given the well-documented presence of asymptomatic AF in patients treated with antiarrhythmic agents, the efficacy of pharmacological interventions on clinical AF burden may be overestimated. Many trials focus on symptomatic recurrence as a
Epidemiology of AF When Asymptomatic AF is Considered
Atrial fibrillation is associated with significant morbidity and is responsible for significant health care expenditures, so it is important to accurately represent its clinical and economic impact. Epidemiological studies of AF are limited by the unreliable methods used to determine cases of arrhythmia, such as extraction of hospitalization data, patient self-reporting, or on screening ECG databases.2, 14 In the ATRIA study, Go et al searched an automated clinical database of patients within a
Thromboembolic Consequences of Asymptomatic AF
Stroke is a devastating consequence of AF. Patients with AF have a 5- to 6-fold increase in stroke risk in comparison to patients in sinus rhythm.20 Evidence from randomized controlled studies supports warfarin use in all patients with one or more risk factors for stroke.21 Warfarin significantly reduces the risk of stroke and has been demonstrated to reduce clinical severity of strokes and mortality in patients who have strokes.22 In assessing stroke risk in individuals with AF, it is
Tachycardia-Induced Cardiomyopathy and Asymptomatic AF
Asymptomatic patients with inadequate rate control may develop significant CHF. Chronic exposure to rapid ventricular rates may result in a partially or completely reversible impairment of LV function. Grogan et al reported significant improvement in LV function in 10 patients who presented to the Mayo Clinic with severe LV dysfunction and AF who were then treated with adequate rate control.33 The mean LV ejection fraction before treatment was 25% (range, 12%-30%) and 52% (range, 40%-64%) after
Conclusion
Asymptomatic AF is common and has significant clinical implications. Asymptomatic AF should be considered in estimating the prevalence of the disease and its impact on health care resources, when interpreting the results of studies reporting the efficacy of various rhythm control strategies (eg, antiarrhythmic agents, AF ablation), and in the day-to-day management of patients suffering from AF. Failure to acknowledge the frequency of asymptomatic AF could lead to devastating consequences,
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2019, American Heart JournalCitation Excerpt :In the Atrial Fibrillation Follow-up Investigation of Rhythm Management Study, 12% of 4,060 trial participants had AF and were asymptomatic, whereas the Framingham Heart Study reported 40% (228/562) of AF to be asymptomatic on routine biennial ECGs.2628 Asymptomatic AF is thought to convey the same risks of thromboembolic events as does symptomatic AF; thus, studies that do not ascertain asymptomatic AF could grossly underestimate the prevalence and prognostic impact of AF.29 The NHLBI has recommended that cohort studies add AF as an end point and furthermore distinguish between asymptomatic and symptomatic events to better characterize the clinical course of AF.30
Role of Geriatric Syndromes in the Management of Atrial Fibrillation in Older Adults: A Narrative Review
2019, Journal of the American Medical Directors AssociationCitation Excerpt :However, 3%-44% of older persons with AF are asymptomatic.12 New research is questioning novel genetic variants associated with these asymptomatic presentations.13,14 AF has been associated with acute states of cognitive dysfunction (ie, delirium) and chronic cognitive dysfunction [ie, mild cognitive impairment (MCI) and dementia], although this association is not consistent across studies.