Detection of Previously Unrecognized (Subclinical) Atrial Fibrillation

Atrial fibrillation (AF) has been associated with increased morbidity and mortality, even when symptoms are absent and the arrhythmia is unrecognized (e.g., subclinical AF [SCAF]). Despite substantial evidence demonstrating an association between AF and adverse outcomes, the role of mass screening for previously unrecognized SCAF, such that its individual and population risks may be reduced by prophylactic therapy, remains uncertain. Many AF screening strategies exist, from pulse palpation and single-use devices to implanted cardiac monitors; however, existing guidelines are insufficient in specifying who to screen and for how long. In general, higher age, more (and more severe) comorbidities, and longer monitoring periods are associated with greater detection of SCAF. Herein we review the significance of previously unrecognized SCAF and current status of SCAF detection methods. We then propose a clinical approach to help clinicians incorporate AF screening into their practice. In conclusion, we report that SCAF may not be rare, that inserted cardiac monitors have the highest yield of SCAF detection, that clinical concern regarding SCAF is appropriate, but that evidence for therapy mandates is still being collected.