The tip of the eventberg: incidental rhythm disturbances by remote monitoring following pulmonary vein isolation

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND/INTRODUCTION: Implantable loop recorders (ILR) are increasingly used for continuous rhythm monitoring following pulmonary vein isolation (PVI) for atrial fibrillation (AF). However, the impact of non-AF episodes in this patient population is unknown. PURPOSE: Firstly, the aim of our study was to asses the incidence of clinically important non-AF events. Secondly, we wanted to identify possible risk factors leading to incidental non-AF events. METHODS: In this retrospective single center study, all patients implanted with ILR following PVI in our center between 2016 and 2022 were analysed. The indication to ILR implantation and remote monitoring after successful PVI was based on patient preference. Transmissions were carefully reviewed by two independent electrophysiologists. Bradycardic events were defined as documented symptomatic bradycardia, AV-Block II˚, AV-Block III˚ or Sick-Sinus Syndrom. Tachycardic events were defined as documented symptomatic supraventricular tachycardia (non-AF) or ventricular tachycardia >160/min with at least 30 seconds duration. RESULTS: A total of 219 patients underwent PVI and consequent ILR implantation. We evaluated a mean 2.1±1.1 years of follow up (FU) with a median 68 events/patient (25th–75th IQR: 13-590 events/patient). Overall, 49 patients (22.4%) developed at least one bradycardic event, 6 patients (2.7%) were later implanted with a pacemaker. In univariate logistic regression analysis age, persistent AF, left atrial diameter and prior cardioversion correlated with an increased risk of bradycardic events. Upon a multivariate logistic regression age and prior cardioversion predicted bradycardic events. At least one tachycardic non-AF event was observed in a total of 9 patients (3.6%). Supraventricular tachycardia was observed by 4 patients (1.8%), one (0.4%) were ablated by an atrioventricular nodal reentry tachycardia (AVNRT), others (1.4%) were ectopic atrial tachycardia treated conservatively. Sustained wide complex tachycardia was recorded in 5 patients (2.2%), thereof two (0.9%) received a secondary prophylactic implantable cardioverter defibrillator (ICD). The multivariate analysis did not show any statistically significant value predicting tachycardic events. CONCLUSION: Use of ILR for rhythm monitoring following PVI could increase the early detection of incidental rhythm events, especially bradycardic episodes. However, to asses this possibly beneficial effect further prospective, multicenter studies are needed. [Figure: see text] [Figure: see text]