Study	Risk
High	Intermediate	Low
Atrial Fibrillation Investigators (1994)	High to intermediate risk:Age >65 yearsHistory of hypertensionDiabetes		Age <65 yearsNo high risk features
American College of Chest Physicians Consensus (1998)	Age >75 yearsHistory of hypertensionLeft ventricular dysfunction†>1 moderate risk factor	Age 65-75 yearsDiabetesCoronary disease (thyrotoxicosis)*	Age <65 yearsNo risk factors
Stroke Prevention in Atrial Fibrillation	Women aged ⩾75 yearsSystolic blood pressure >160 mm HgLeft ventricular dysfunction‡	History of hypertensionNo high risk features	No high risk featuresNo history of hypertension
Lip (1999)	Patients aged >75 years and with diabetes or hypertensionPatients with clinical evidence of heart failure, thyroid disease, and impaired left ventricular function on echocardiography§	Patients aged <65 years with clinical risk factors: diabetes, hypertension, peripheral arterial disease, ischaemic heart diseasePatients aged >65 not in high risk group	Patients aged <65 years withno risk factors