Atrial fibrillation is very common; the estimated prevalence increases with age from about 0.1% in adults under age 55 years to 9% of those 80 years of age or older. AF is associated with a reduced quality of life due to the irregular heart rate and reduction in cardiac output. More importantly, AF is associated with an increased risk of thromboembolic events, with an annual stroke risk ranging from as low as <1% in patients with isolated AF to as high as 12% depending on additive risk factors including age over 75 years, female sex, diabetes, hypertension, heart failure, vascular disease or a prior stroke. Stroke risk is even higher in those with AF due to valvular heart disease. Thus, lifelong oral anticoagulant therapy is recommended in most patients to reduce stroke risk.

The presumed pathophysiology of stroke in patients with AF is that stasis of blood flow in the left atrium leads to thrombus formation, most often (90%) in the left atrial appendage (LAA). Thus, there has been considerable interest in the idea of removing or occluding the LAA to prevent thromboembolic events with the hope of avoiding long-term oral anticoagulant therapy. However, even though LAA occluder devices have been available in Europe for several years and one was recently approved in the USA, this approach remains controversial.

In this issue of Heart Dr López Mínguez and colleagues …