Abstract 11206: Clinical Utility of a Novel Wireless Implantable Loop Recorder in the Evaluation of Patients with Unexplained Syncope
Introduction: Implantable loop recorders (ILRs) are used in pts with unexplained syncope. Ideally, pts activate the ILR at the time of recurrent syncope, however, pts often fail or are unable to do so. Although ILRs are capable of “auto-activation,” limited storage capacity can cause events to be overwritten if recurrent. A wireless ILR, briefly available in the US, overcame this limitation by wirelessly transmitting auto-activations immediately to physicians. We sought to evaluate the clinical utility of such a system.
Methods: Consecutive pts with unexplained syncope implanted with a SLEUTH ILR (Transoma Medical, Arden Hills, MN) were evaluated. All pts received a hand-held device that wirelessly retrieved ECG data from the ILR and transmitted it to a third-party monitoring center (MEDICOMP Inc., Melbourne, FL). All events were adjudicated; physicians were notified immediately if an event met pre-specified criteria. Primary endpoint was time to diagnosis.
Results: 50 pts (age 70 ±1 6 yrs; 36% M; all with EF ≥ 40%) were implanted. During a follow-up of 293 ± 211 days, 12 (24%) pts had recurrent syncope (Figure) due to bradycardia (n=7), SVT (n=3), and presumed vasovagal (n=2). Of the 7 pts with bradycardia, 6 (86%) had an auto-activation only (mean pause 5.1 ± 1.3 secs) as opposed to only a single patient activation (16.9 sec pause). The median time from event to physician notification was 145 min, (IQR 80, 173 min). The greatest diagnostic yield was observed within the first 6 months of ILR implant.
Conclusions: In pts receiving an ILR for evaluation of unexplained syncope, a diagnosis (most commonly significant bradycardia) was most often made within 6 mos. Importantly, pts frequently failed to activate their ILR; thus the majority of these episodes could have been missed if auto-activations were not available. These initial data demonstrate the clinical advantage of ILRs with wireless data transmission capabilities in pts with unexplained syncope.
- © 2010 by American Heart Association, Inc.