Introduction Implantable Loop Recorders (ILR) permit long term electrocardiographic monitoring allowing symptom-rhythm correlation in children who are suspected to have an arrhythmia. We reviewed the presenting complaint and previous investigations in order to aid patient selection for the ILR.

Method We conducted a retrospective review identifying patients 16 years and younger with structurally normal hearts undergoing ILR implantation in Bristol Children’s Hospital through the Heartsuite database over a 10 year period from 2004 – 2014. Statistical analysis was performed with the Fishers exact probability test.

Results One hundred children were identified. Mean age was 11.0 years (range 1.2 – 16.9 years) with a male: female ratio of 1.2:1. The predominating complaint was syncope in 62.7%, palpitations in 32.5% and dizziness in 4.8%. Eighty-three of the 100 children had explantation data (8 patients had follow-up out of region, 9 ILR remained in situ) with 79 having a documented ECG/Holter prior to ILR. Overall 24/79 (30%) of patients required intervention following ILR implantation, either permanent pacemaker (PPM) (n = 7), medication or ablation (n = 17). There was a significantly higher number of patients requiring intervention post ILR if the prior ECG/Holter was abnormal (Table 1).

Fifty percent (13/26) of patients presenting with palpitations required further intervention for an arrhythmia identified on the ILR compared with 20% (10/49) of those presenting with syncope (p = 00.01). Of those presenting with syncope, a PPM was required in 5/22 (23%) with an abnormal ECG/Holter compared with 2/27 (7%) with a normal ECG/Holter (p = 00.2). None of the children presenting with palpitations or dizziness required PPM placement. Use of event recorders was low (6/79, 7.6%). Incidence of complication was 5% with 2 infections (1 requiring removal of the ILR, 1 treatment with antibiotics), 1 hypertrophic scar and 1 re-implanted due to discomfort.

Conclusions Presenting complaint does seem to influence the outcome following ILR implantation. The need for further intervention following ILR implantation was more likely if children present with an abnormal ECG/Holter monitor. Therefore longer-term non-invasive monitoring could be justified in those with normal ECG/Holter monitoring rather than using ILR’s. Further prospective study and protocol development is warranted in order to establish the perfect patient selection.