Atrial fibrillation (AF) is the most common arrhythmia that occurs in clinical practice. It is rare in children and becomes more common with aging, with a prevalence approaching 20% in patients over 85 years of age. AF activates the upper chambers of the heart (the atria) very rapidly and irregularly, so that their contraction ceases to be effective. Lack of atrial contraction allows blood to stagnate in certain parts of the atria, particularly the appendages (which are blind sacks at the top of each atrium), promoting blood-clot formation. When clots break off, they can fly off into distant parts of the vascular tree, blocking off key blood vessels and causing complications like strokes. In addition, rapidly-firing atria drive the pumping parts of the heart, the ventricles, at rapid and irregular rates, interfering with optimal mechanical (pumping) function of the heart.

AF has a wide range of potential complications and contributes to cardiovascular morbidity and mortality in important ways. For example, AF is the single most common factor associated with stroke in the elderly. It also causes particularly large and devastating strokes, and may contribute to more subtle forms of mental deterioration in the elderly. Presently-available approaches to AF treatment have major limitations, including inadequate efficacy and significant adverse effect risks, the most worrisome of which is life-threatening ventricular proarrhythmia. The inadequacy of available therapies have inspired major efforts to improve our understanding of AF mechanisms, with the premise that better mechanistic insights will lead to the development of improved therapeutic approaches.

The ENAFRA network brings together a number of world-class centers in Europe and North America, in an attempt to accelerate research into the causes of atrial fibrillation, with the hope of developing better ways to diagnose, prevent and treat this important problem.