Background: Implantable loop recorder (ILR) use improves diagnostic yield in patients with unexplained syncope allowing for earlier diagnosis and interventions. We sought to determine whether syncope duration was associated with an ILR-guided intervention.
Methods: One hundred and one consecutive patients underwent an ILR implant. Patients with syncope/pre-syncope were included. Data were collected on baseline demographics, symptom duration, symptom frequency and baseline electrocardiogram (ECG) abnormalities. The primary outcome was ILR-guided intervention. Univariate and multivariate analysis was performed.
Results: Seventy-five patients (age 64 ± 20 years, 60 % male) with syncope (92%) and pre-syncope (8%) were included. Symptoms were predominantly recurrent (77%) and occurring within 3 months prior to evaluation (59%) with median duration of symptoms 2 months (interquartile range 1–9). Structural heart disease was present in 11%. Baseline ECG abnormalities were present in 33 patients (44%) and commonly included right bundle branch block (n=8), sinus bradycardia (n=5), atrial fibrillation (n=4) and left bundle branch block (n=4). After a mean follow up of 10 ± 2.4 months, symptom recurrence occurred in 23 patients (31%). ILR-guided diagnoses included reflex syncope (n=10), bradyarrhythmia (n=9), tachyarrhythmia (n=2) and orthostatic hypotension (n=2). ILR-guided interventions were undertaken in 12 patients (16%) and included permanent pacemaker implantation (n=7) and initiation of anticoagulation (n=4) or beta-blocker therapy (n=1). Patients with an ILR-guided intervention were significantly older (intervention versus no intervention 76 ± 16 versus 62 ± 21 years, p=0.040) and a greater proportion had symptoms within 3 months of evaluation (92 versus 50%, p=0.008). Symptom duration remained significant after adjusting for age. Gender, baseline ECG abnormalities and structural heart disease were not significantly associated with an ILR guided-intervention.
Conclusions: Our preliminary results suggest that ILR-guided interventions in patients with syncope are more likely to occur in older patients and those with syncope occurring within 3 months of evaluation. This highlights the importance of considering ILR implant early, especially in those >75 years with recent onset of syncope.