Screening for atrial fibrillation: a call for evidence

Abstract

Atrial fibrillation (AF) is the most common cardiac arrhythmia and prevalence is predicted to double over the next 30 years due to changing demographics and the rise in prevalence of risk factors such as hypertension and diabetes. Atrial fibrillation is associated with a five-fold increased stroke risk, but anticoagulation in eligible patients can reduce this risk by around 65%. Many people with AF currently go undetected and therefore untreated, either because they are asymptomatic or because they have paroxysmal AF. Screening has been suggested as one approach to increase AF detection rates and reduce the incidence of ischaemic stroke by earlier initiation of anticoagulation therapy. However, international taskforces currently recommend against screening, citing the cost implications and uncertainty over the benefits of a systematic screening programme compared to usual care. A number of large randomized controlled trials have commenced to determine the cost-effectiveness and clinical benefit of screening using a range of devices and across different populations. The recent AppleWatch study demonstrates how advances in technology are providing the public with self-screening devices that are increasingly affordable and accessible. Health care professionals should be aware of the implications of these emerging data for diagnostic pathways and treatment. This review provides an overview of the gaps in the current evidence and a summary of the arguments for and against screening.

Keywords: Anticoagulation; Atrial fibrillation; Screening; Stroke.

Figure 1

Kaplan–Meier estimates of cumulative incidence of subclinical atrial fibrillation (SCAF) >6 min, >6 h, and >24 h. Reproduced from the Van Gelder et al.

Figure 2

Extended Kaplan–Meier curves of ischaemic stroke/systemic embolism stratified by time-dependent durations of subclinical atrial fibrillation (SCAF). Reproduced from the Van Gelder et al.

Figure 3

Prevalence of asymptomatic atrial fibrillation by screening method and stroke risk score.

Figure 4

Examples of devices used to detect atrial fibrillation and how they record the arrhythmia.

Take home figure

Evidence uncertainties in atrial fibrillation screening.