Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with a prevalence of 1% to 2% in the general population; this increases with age, reaching >8% in subjects over 80 years of age.1,2 The arrhythmia is independently associated with an increased risk of stroke, which is about 5-fold higher in AF-affected patients than in controls.3 AF is considered to be the cause of ischemic stroke in 15% to 17% of cases.3,4 Interestingly, AF-related strokes cause higher mortality and disability than strokes unrelated to AF4,5 and stroke risk is independent of the type of AF (paroxysmal, persistent, or permanent).6,7 The rate of stroke caused by AF can be significantly reduced (by 60% to 70%) by the use of warfarin or novel oral anticoagulants.8,9 Article see p 263 AF is usually symptomatic, causing symptoms, such as palpitations, dyspnea, fatigue, angina, dizziness, and syncope.10 Not rarely, however, the arrhythmia is not perceived at all by the patient and, in this case, is defined as asymptomatic, silent, undetected, occult, or subclinical AF. According to the EURObservational Research Programme–AF (EORP-AF) Pilot General Registry, almost 40% of the AF patients who are seen in daily cardiology practice are completely asymptomatic, and another 30% have only mild symptoms.11 The prevalence of silent AF varies in different clinical settings, ranging from 0% to 31% in postablation patients12,13 to 16% to 25% as incidental finding at standard ECG,2,14 54% to 70% in patients treated with antiarrhythmic drugs, and 15,16 up to 51% to 74% in pacemaker/implantable cardioverter- defibrillator recipients.17,18 Stroke is the leading cause of long-term adult disability and mortality in the developed world. Approximately, 30% to 40% of …