Atrial fibrillation and stroke risk

Every year, 15 million people suffer a stroke globally, with 5 million losing their lives and another 5 million left permanently disabled (WHO). Cardioembolic stroke, the most severe subtype of ischemic stroke, accounts for approximately 22% of stroke incidence worldwide, and data indicates that, in developed countries, the proportion of cardioembolic stroke reaches over 50%. One explanation might be that atrial fibrillation (AF), one of the most discussed risk factors of cardioembolic stroke, has a higher prevalence in developed countries.

The most significant risk factor of cardioembolic stroke, AF, has a general prevalence of about 1,9-2,9% in the European population and the prevalence increases with age, approaching 17% in the population aged 80 or above. The high prevalence coupled with the fact that AF causes a 4-5 times increase in the risk of stroke.

Clinically the risk of stroke in a patient with AF, independent of type, is today estimated with a clinical scoring instrument like CHA₂DS₂-VA. However, these instruments have been shown to predict high-risk individuals only modestly, indicating an important need for further improvement in the risk stratification of AF patients.