Table 2

Schemes for stratification of stroke risk in non-valvar atrial fibrillation

	High risk	Moderate risk	Low risk
Untreated patients
Atrial Fibrillation Investigators (1994)11	Age ⩾ 65 years History of hypertension Diabetes Prior stroke/TIA		Age < 65 years No high risk features
Observed stroke rate	5.1%/year	NA	1.0%/year

American College of Chest Physicians Consensus (1998)14	Age > 75 years History of hypertension Prior stroke/TIA Left ventricular dysfunction^2-150 > 1 moderate risk factor	Age 65-75 years Diabetes Coronary disease Thyrotoxicosis	Age < 65 years No risk factors
Observed stroke rate	NA	NA	NA

Aspirin treated patients
Stroke Prevention in Atrial Fibrillation (1995)12	Women > 75 years Systolic BP > 160 mm Hg Prior stroke/TIA Left ventricular dysfunction^2-151	History of hypertension No high risk features	No high risk features No history of hypertension
Observed stroke rate	7.7%/year	3.6%/year	1.1%/year

SPAF Exploratory Analysis (1999)13	Women > 75 years Systolic > 160 mm Hg Hypertension plus age > 75 Prior stroke/TIA	Hypertension and age ⩽ 75 years Diabetes No high risk features	No high or moderate risk features
Observed stroke rate	7.1%/year	2.6%/year	0.9%/year

↵2-150 Moderate to severe left ventricular systolic dysfunction on echocardiography or recent congestive heart failure.
↵2-151 Impaired left ventricular function included recent congestive heart failure or fractional shortening ⩽ 25% by M mode echocardiography.
TIA, transient ischaemic attack.