Early atrial fibrillation detection is associated with higher arrhythmic burden in patients with loop recorder after an embolic stroke of undetermined source

Background: After an embolic stroke of undetermined source (ESUS), long-term monitoring is recommended to start an anticoagulation therapy in patients with documented atrial fibrillation (AF). Literature is sparse about the AF burden following an ESUS, although this might have significant implications in terms of clinical man-agement and therapeutic strategy. Our primary aim was to evaluate a possible association between early detection of AF (within 90 days from the ILR implantation) and higher AF burden. Methods: This is a retrospective single-center study of 129 consecutive patients who received implantable loop recorders (ILRs) after an ESUS for detection of subclinical AF and their AF burden. Results: Mean age was 70.3 +/- 10.4 years old (males: 51.9%). Atrial fibrillation was found in 40.3% of patients. Patients with AF were older, presented a higher CHAD2S2-Vasc Score and greater left atrial volume compared with patients without AF. The median AF burden was 1.2%; 59% of patients had the first AF episode within 90 days from the ILR implant while 41% experienced the first episode later than 90 days. The AF burden was significantly higher in the former group. Of note, the univariate analysis showed that only early AF detection was significantly associated with AF burden >1% (OR 20.0; 95% CI 1.68-238.6, p = 0.01). Conclusions: The early AF detection was found to be significantly associated with a higher burden of AF.