Aims: This prospective randomized controlled study evaluated the first-line use of a novel remotely monitored implantable loop recorder (ILR) in the initial investigation of unexplained syncope, and compared this to conventional therapy and a dedicated Syncope Clinic (SC).
Methods and results: A total of 246 patients (mean age 70.3 years) were randomly allocated to conventional management, SC alone, ILR alone, or SC + ILR. Median follow-up was 20 months (IQR 15-25 months). Time to electrocardiogram (ECG) diagnosis was significantly shorter with ILR alone vs. conventional [hazard ratio (HR) 35.5, P = 0.0004] and with SC vs. conventional (HR 25.6, P = 0.002). Seventy-four per cent of first syncopal events documented in the SC groups occurred during provocative tilt testing. Twenty-two per cent of patients who received an ILR were found to have a bradycardia indication for permanent pacing, compared with 3% of patients who did not. Overall, more investigative tests were undertaken in the conventional group than in any other. Only patients who received an ILR had a significant increase in time to second syncope (P = 0.02), suggesting successful diagnosis and management of treatable causes of syncope.
Conclusions: Implantable loop recorder monitoring achieved a more rapid diagnosis in unexplained syncope than usual care. Conventional management of syncope failed to achieve an ECG diagnosis despite a large number of investigative tests. Syncope Clinic and provocative tilt testing delivered a rapid ECG diagnosis, but did not prevent recurrent syncope. Implantable loop recorders offered rapid diagnosis, increased the likelihood of syncope being reported, demonstrated a high rate of intermittent bradycardia requiring pacing, and reduced recurrent syncope.
Keywords: Implantable loop recorder; Syncope.
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