Atrial fibrillation (AF) may occur in the absence of identifiable causes, co-morbidities or structural cardiac disease (lone AF).
Silent AF is common and patients may have a completely asymptomatic arrhythmia or may experience both symptomatic and asymptomatic
AF episodes. It has been estimated that among patients with recognized AF, one third has no appreciable symptoms. In contemporary
clinical practice, AF remains largely underdiagnosed and 25% of patients with AF-associated cardioembolic stroke have not been
previously diagnosed with AF. The strategies for AF screening include opportunistic and systematic screening. Several methods for AF
detection are nowadays available: from very simple (pulse palpation) to more advanced technologies proposed for ambulatory external
monitoring of variable time duration. In patients previously implanted with cardiac electrical devices with an atrial lead, according to current
clinical indications, the ability to continuously detect AF and to monitor its evolution is magnified, and AF burden can be precisely
measured and monitored along with time. Similar information on AF burden can be also obtained by implantation of subcutaneous cardiac
monitors that rely on the analysis of consecutive RR intervals for the diagnosis of AF. The prognosis is generally favorable for patients
presenting with lone AF, but adverse outcomes, including stroke and thromboembolic events may occur at long term, in association
with aging, or the development of underlying heart disease, or progression from paroxysmal to permanent AF. In this respect, the role of
new technologies and diagnostic tools for AF detection and monitoring should be fully defined.