Methods, accuracy and clinical implications of atrial fibrillation detection by cardiac implantable electronic devices

Atrial fibrillation (AF) is the most common arrhythmia in the developed countries and is associated with an increased risk of thromboembolic events and heart failure. Episodes of AF are often asymptomatic and intermittent, eluding diagnosis with non-continuous monitoring techniques. Cardiac implantable electronic devices (CIEDs) represent the gold standard for detecting asymptomatic AF. Improper CIED programming may however increase the risk of false-positive detection of atrial tachyarrhythmias, leading to inappropriate clinical management of patients. A faster rate and a longer duration of the tachyarrhythmic episodes, in addition to a greater AT/AF burden, have been proposed as potential criteria for differentiating between CIED-detected atrial tachyarrhythmias and true AF. Nonetheless, manual overreading of intracardiac electrograms recorded by the CIED remains crucial for a correct diagnosis. Asymptomatic atrial tachyarrhythmias may carry a higher risk of systemic thromboembolism, though clinical thromboembolic risk factors seem to play a greater if not absolute role in prognostication. In addition, there is no clear temporal relationship between CIED-detected atrial tachyarrhythmias and stroke, and the anticoagulation strategy to be pursued in these patients is still a matter of debate and the focus of current prospective randomized studies.