Fifteen per cent of
cerebrovascular accidents have a cardiac origin, two thirds of which are due to
atrial fibrillation (AF). The Framingham study showed the risk of an ischaemic cerebral event to be increased by 5.6 in AF unrelated to
rheumatic heart disease and by 17.5 when AF is associated with
valvular heart disease. The risk of
embolism is higher in elderly subjects and in those with underlying
cardiac disease. Other high risk conditions include
hypertension, diabetes,
hyperthyroidism and cases with echocardiographic changes: left atrial dilatation, pre-thrombotic state or intra-atrial
thrombus,
atheroma of the ascending aorta. This stratification of risk should be taken into account when deciding on treatment. Conscious of the importance of the risk of
embolism in AF, several authors have undertaken, over the last few years, randomised studies of the prevention of thromboembolic complications of AF: the AFASAK, BAATAF,
SPAF and SPINAF trials. All showed the unquestionable efficacy of
warfarin, even at low doses, at the price of a haemorrhagic risk of less than 2% per year for severe haemorrhages. A more recent study (
SPAF II) confirmed the value of
aspirin at the dosage of 325 mg/day which would seem to be a good alternative to
anticoagulant therapy when this is contraindicated, although
aspirin is less effective. The indications for
anticoagulant therapy have become clearer since the publication of these results.
Anticoagulant therapy is essential in permanent AF whether or not associated with
rheumatic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)