Atrial fibrillation subtypes, risk of stroke, and antithrombotic therapy

Abstract

Despite a significant decline in the last 50 years, stroke remains the third leading cause of mortality in men and the second in women.1 Stroke also represents the leading cause of disability and the second of dementia, with a tremendous impact on the affected patients and their relatives. Approximately one-third of ischaemic strokes are caused by an embolus originating from the heart, and in the majority of these cases atrial fibrillation is responsible for the thromboembolic event. This proportion may be even higher, as the role of atrial fibrillation in the pathogenesis of stroke may be underestimated. In fact, the observation of sinus rhythm on the surface electrocardiogram at hospital admission for stroke, in the absence of clinical history of atrial fibrillation, does not rule out the possibility of a new-onset and self-terminating arrhythmic episode that preceded the occurrence of neurological symptoms. Close electrocardiographic monitoring may increase the detection of atrial fibrillation among stroke patients, but at present it can be performed only in the limited number of available stroke units. Atrial fibrillation is indeed one of the most important risk factors for stroke.2 The rate of ischaemic stroke among patients with atrial fibrillation averages 4.5% per year, which is 4–5 times more than in patients without atrial fibrillation, and the risk significantly increases with age.3 After 80 years of age, the annual rate of stroke in patients with atrial fibrillation reaches the staggering figure of 25%.4 Stroke due to atrial fibrillation is also associated with larger cerebral infarcts and a higher neurological impairment. As a consequence, the outcome of patients with atrial fibrillation who suffer a stroke is worse, as they show a greater degree of disability. The risk of stroke in … *Corresponding author. Tel: +39 02 619112850, Fax: +39 02 619112850, Email: stramba_badiale{at}auxologico.it