595 LOW INCIDENCE OF ARRHYTHMIC SYNCOPE AND PACEMAKER IMPLANTATION IN OLDER PATIENTS WITH BIFASCICULAR BLOCK AND IMPLANTABLE CARDIAC MONITOR

Abstract Background In patients with unexplained syncope, bifascicular block (BFB) is considered associated syncope due to either heart or sinus arrest. Immediate delayed pacemaker (PM) implantation after ECG documentation of syncopal recurrence by means implantable cardiac monitors (ICM) still debated. We aimed assess the incidence recurrent and guideline-based PM in BFB implanted ICM. Methods Consecutive followed at two tertiary care units ICM from 2012 2020 were retrospectively reviewed. Only >2 clinical visits >18 years age included. Incidence a Class I indication for was primary outcome. Results Of 635 an ICM, 55 (8.7%) had Median 75 [interquartile range, IQR:64-81] years, 28(49.1%) women. At 26 [IQR:12-41] months follow-up, 20 (36.3%,16.3%/year) experienced syncope: 6(10.9%) classified ‘arrhythmic’ higher prevalence older individuals (p=0.048). (N=14,25.5%) more frequent >75 (p=0.024). survival analysis, highest risk arrhythmic guideline directed (Hazard Ratio: 4.5, 95% Confidence Intervals 1.5-13.3). Conclusions Most who received didn't have events during follow-up. one-in-three even smaller number implantation. Older strongly