Abstract 13783: Near-Real Time Extended Ambulatory ECG Monitoring in Patients With Syncope Unveils a Spectrum of Arrhythmias and High Incidence of Atrial Fibrillation

Abstract

Introduction: Patients (pts) with a history of syncope are at high risk for sudden death with a reported 1-year mortality rate of 30%. Triaging relevant arrhythmias (ars) in a timely manner in this population is critical to allow for potential life-saving interventions. For example screening atrial fibrillation (AF) studies of pts with no known AF, reported an AF detection of 4.5% to 5.3%. It is unknown if these findings extend to a syncope population. A recent syncope study reported most significant ars occurred outside the typical window of a hospital stay. Therefore, this study aims to analyze a proprietary Zio AT database containing arrhythmia findings of pts monitored for the diagnosis of syncope. Methods: Data retrospectively analyzed 10,643 pts from US institutions with a syncope indication for monitoring. Pts with recordings between July 2017 to December 2021 were analyzed. All ars transmitted via cellular gateway during the wear period and full ECG download at end of wear were analyzed with a validated proprietary AI algorithm, then followed by a certified cardiographic technician review. Ars were defined as: AF, ≥30 seconds at any heart rate; SVT, ≥90 bpm for ≥4 S beats; Pause, ≥3 second; AV Block, any 3rd or 2nd degree AV Block (Mobitz I or II); VT, ≥100 bpm for ≥4 V beats or PVT, TdP, VF. Detected ars were characterized by duration, episode counts, rates, and/or burden (where applicable). Results: Of the 10,643 pts studied (49% female, mean age 65.4 years, mean wear 11.9 ± 3.6 days), 8,442 (79%) had at least 1 arrhythmia detected, with 3,107 (29%) having 2 or more arrhythmia types. Most common ars detected in this patient population were SVT (69%; 7365/10643), VT (26%; 2716/10643), and AF (9.5%; 1015/10643). AV Blocks (3.6%; 382/10643) and Pauses (6.2%; 662/10643) were not uncommon. Surprisingly, the most common arrhythmia to trigger a notification alert was AF/AFL (8.5%). Average time until first AF detection was 1.4 ± 2.8 days for all AF subjects and 2.8 ± 3.5 days for paroxysmal AF subjects. Conclusions: In this large retrospective study, ambulatory ECG monitoring with ZIO AT in syncope indicated pts revealed an unexpectedly high incidence of AF and SVT. Further analysis of this group may help clinicians focus a heightened awareness of atrial ars in this population.