The emerging role of biomarkers in atrial fibrillation.

Improved diagnostic techniques have identified various biomarkers that might play an important role in prediction of atrial fibrillation (AF) and related outcomes (cardio- and cerebrovascular events, and mortality and rhythm outcomes). Biomarkers can include blood markers (e.g., von Willebrand factor, D-dimer, natriuretic peptides, etc.), urine (e.g., proteinuria, estimated glomerular filtration rate, or creatinine clearance), cardiac imaging (echocardiography; transthoracic or transoesophageal), or cerebral imaging (e.g., computed tomography or magnetic resonance imaging), which can provide additional refinement to clinical stroke risk stratification for identification of "high risk" subjects. Although inclusion of some blood-based biomarkers (e.g., von Willebrand factor, D-dimer) in existing clinical stroke risk stratification schemes might improve their predictive value for identifying "high risk" patients, this concept might be outdated and overtaken by new developments in thromboprophylaxis (which now focus on initial identification of "low risk" patients who do not need any antithrombotic therapy, followed by patients with 1 or more stroke risk factors, to whom anticoagulation can be offered), and additional questionable practicality in "everyday" practice. Biomarkers could be applied as a "rule out" approach or as surrogates of anticoagulation efficacy in trials of new antithrombotic strategies. The present review aims to provide an update of the role of biomarkers in AF, with particular focus on AF outcomes.