AF Screening: The Tools Are Ready, But Should We Do It?

Abstract and Introduction

Introduction

Screening of diseases is intended to improve health at a population level. The World Health Organization has put forward prerequisite principles for screening (Figure).^[1] Atrial fibrillation (AF) fulfills the first 4 principles: It is the most common sustained cardiac arrhythmia and is associated with dire adverse outcomes (eg, stroke and death), which can in part be prevented by oral anticoagulation.^[2,3] Because AF may be silent and paroxysmal, it can be difficult to ascertain, leading to missed opportunities to prevent adverse outcomes. Longer or more frequent electrocardiographic recordings increase the diagnostic yield.^[4] The intuitive premise behind mass screening of AF is that it will result in improved outcomes through reliable identification of AF, initiation of anticoagulation, and prevention of stroke and systemic embolism.

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Figure.

WHO-recommended principles for screening.
Colors illustrate compliance with screening principles for atrial fibrillation (green, fulfilled; orange, debated or dependent on the tool used; red, not demonstrated). WHO indicates World Health Organization.

Recording short-duration electrocardiographic strips is cheap, harmless, widely accessible, and well accepted, fulfilling World Health Organization principles 5 and 6, and is therefore a good candidate screening tool for asymptomatic AF. However, it is critical to evaluate the ability of systematic ECG recordings to identify patients with unknown AF. The VITAL-AF trial (Screening for Atrial Fibrillation Among Older Patients in Primary Care Clinics),^[5] discussed in this issue of Circulation, is an important contribution in this regard. Lubitz et al^[5] tested the hypothesis that point-of-care electrocardiographic screening during primary practice visits of patients ≥65 years of age would identify more patients with AF than routine care. A total of 30 715 patients were included in a pragmatic, cluster-randomized controlled trial. Among 15 393 patients randomized to screening, 91% had an electrocardiographic recording with a handheld single-lead electrocardiographic device. At 1 year, newly diagnosed AF (cardiologist adjudicated) did not differ between groups (1.59% versus 1.72%, respectively; risk difference, 0.13 [95% CI, −0.16 to 0.42]; P=0.38).^[5] Furthermore, rates of new prescriptions of oral anticoagulants during the study or the proportion of individuals with newly diagnosed AF initiated on oral anticoagulants did not differ between groups. These results do not support the widely held belief that widespread screening for AF with the ECG will be effective at improving the rate of use of anticoagulation. Yet this large, well-conducted trial underlines the importance of (1) careful selection of the target population, (2) choosing the appropriate screening tools, and (3) demonstrating an impact on outcome.