Challenging anticoagulation decisions in atrial fibrillation: a narrative review

Atrial fibrillation (AF) is common and warrants consideration of oral anticoagulant (OAC) medication. Usually, the decision is straightforward, following the pathway outlined in the European Society of Cardiology's guideline; however, certain situations fall outside of this evidence base - such as a diagnosis of subclinical AF made via implanted devices or wearable electrocardiogram monitors, or alternatively diagnosis of 'secondary AF' following a major stressor. Subclinical AF is associated with stroke, though not to the extent of clinical AF, and the benefits of anticoagulation appear to be lower. Longer episodes are more clinically meaningful, and recent randomised controlled trials have demonstrated that some patients derive benefit from OAC. Similarly, when AF is triggered by sepsis or non-cardiac surgery, specific evidence supporting OAC initiation is lacking and clinician behaviour is variable. Observational data demonstrate poorer outcomes in these patients, implying that the perception of a transient, reversible phenomenon may not be correct. Contrastingly, cardiac surgery very frequently induces AF, and the benefits of anticoagulation rarely outweigh the risks of bleeding. Following ischaemic stroke, recent evidence suggests that early (re-)initiation of OAC should be considered as this does not increase the risk of haemorrhagic transformation as previously hypothesised. This narrative review summarises the available literature and outlines, where possible, practical advice for clinicians facing these common clinical dilemmas.