CONGRESS ABSTRACT

Background: Implantable Loop Recorder (ILR) has various indications for monitoring patients in different clinical settings. Most studies focus on a single indication without comprehensively evaluating the clinical impact of ILR. This study aims to retrospectively review a single experience regarding the actual role of ILR.
Methods: Patients were enrolled from March 2015 to April 2023 due to: syncope of unknown etiology, embolic stroke of undetermined source (ESUS), palpitation, monitoring of arrhythmias in Brugada syndrome (BrS), and following a pulmonary vein isolation (PVI). A change in the clinical course (cardiac implantable electrical devices (CIEDs) implantation, start of anticoagulation therapy, execution of an electrophysiologic study, ablation for tachyarrhythmias or PVI ablation) due to an ILR finding was considered as the primary endpoint. An unexpected result was defined as a different clinical finding from the expected for the cause of ILR implantation (ex. the finding of an atrioventricular block in a patient implanted for ESUS).
Results: 130 patients of which 58 (44%) were females with a mean age of 58 ± 6 years were enrolled. The indication for implant resulted to be ESUS (25/130, 19%), syncope (38/130, 29%), palpitation (18/130 14%), BrS (24/130 28%), or after PVI follow-up (25/130 20%). A change in clinical course was reached in 44 (33%) patients after 12 ± 8 months of follow-up. Ten (8%) patients had a double event. The change of the clinical course was more frequent in female sex than in males (26/58 [45%] vs. 18/72 [25%] patients, p =0.025). In patients with syncope, a CIED was implanted in 7 (24 %) patients but interestingly 7 tachyarrhythmias events (5 AF and 2 SVT) were incidentally detected. In the stroke group, 6 (24%) started anticoagulation therapy after AF detection, and 3 (12%) CIEDs were implanted due to bradyarrhythmia. ILR allowed the diagnosis of tachyarrhythmia in 4 (22%) patients implanted for palpitation. In the syncope and ESUS group, no difference between expected diagnosis and unexpected events was found (syncope 7/38 [18%] vs. 9/38 [24%], p= 0.32; ESUS 3/25 [12%] vs. 6/25 [24%], p = 0.55).
Conclusions: ILR impacted on clinical pathway in 33% of patients during 12 ± 8 months of follow-up. Despite the reason for its implantation, it remains a useful tool for diagnosing other arrhythmias and the consequent changing of therapeutical approach. ILR had more impact in changing the clinical course in females than in males.