Optimal duration of monitoring in patients with unexplained syncope

The optimal duration of monitoring of patients with recurrent unexplained syncope who undergo prolonged monitoring with an implantable loop recorder is unknown. We examined the probability of syncope in a group of 167 patients with this condition who underwent prolonged monitoring with an implantable loop recorder. A 12-month monitoring period appears to capture >90% of episodes. Syncope is most likely to occur in younger patients with less heart disease and more frequent syncope. There is a low risk of syncope after 1 year of monitoring without an event.