How Much Atrial Fibrillation is Enough to Warrant Oral Anticoagulation: Management of Subclinical Atrial Fibrillation?

Stroke due to atrial fibrillation (AF) is common, the cause of significant morbidity and mortality, but is highly preventable with the appropriate use of oral anticoagulants. Recent advances in implantable and wearable electrocardiographic (ECG) technologies now allow continuous monitoring of a patient’s heart rhythm for months or years at a time. Cohort studies have shown that using such methods, it is very common to find asymptomatic, short-lasting episodes of subclinical AF. Subclinical AF is also associated with an increased risk of stroke; however, the risk is lower than with traditional, ECG-detected AF and the absolute risk appears to depend on the overall burden of AF. There is currently great uncertainty as to what duration of AF should trigger the use of oral anticoagulation in specific patient groups. Large randomized trials are underway to help clarify this issue; however, in the meantime, researchers and guideline committees have proposed some guidance to assist clinicians.