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Abstract
Introduction Implantable loop recorders (ILR) allow prolonged monitoring of cardiac rhythm to assist in the diagnosis of clinically important arrhythmias. Indications include: syncope, palpitation and cryptogenic stroke.
However, ILRs are considerably more expensive than conventional monitoring and require clinical time to implant and to review downloaded traces.
Previous studies have shown that for recurrent syncope ILRs detected a cardiac cause in 59% of patients.
Data from Medtronic show the expected detection rate for atrial fibrillation (AF) is 40%.
A retrospective study across the three hospitals of Mid and South Essex Trust (MSE) was conducted for all patients with an ILR implanted in 2022.
Methods A total of 222 patients, 110 male, 112 female had an ILR in 2022.
We recorded the referring hospital (Southend n=162, Basildon n=48, Broomfield n=7), grade of referring clinician, clinical indication, ? significant arrhythmia detected and time from implant until detected event.
Significant arrhythmias were defined as: Pauses >3 seconds, new AF, SVT, 2nd or 3rd degree AV block.
Results 5 patients were removed from the analysis due to lack of clinical information.
The mean time from implant to detection of significant arrhythmia was 4 months.
The success rates for arrhythmia diagnosis were similar for each hospital within the trust (40%, 42% and 43% for Southend, Basildon and Broomfield respectively)
A total of 102 ILRs were implanted to investigate possible bradyarrhythmia. Of these, 45 detected a significant pause, a diagnostic rate of 44%.
Of the 55 ILRs implanted to investigate palpitation, 19 significant tachyarrhythmias were identified, a rate of 35%.
There were 42 ILRs inserted to investigate AF as a cause of stroke. Six cases of prolonged AF (>30 minutes) were identified, a rate of 14%.
At Southend Hospital, 59% of ILR requests were from consultants, at Basildon 79% and at Broomfield 86% were consultant requests.
The diagnostic yield for clinically significant arrhythmias from consultant referrals was: Southend 37%, Basildon 33% and Broomfield 31%.
For non-consultant referrals the yield was: 45% Southend, 40% Basildon and 100% Broomfield.
Conclusions This retrospective evaluation has shown that ILRs were more likely to diagnose clinically significant bradyarrhythmias compared to tachyarrhythmias.
The diagnostic accuracy was slightly lower for consultant compared to non-consultant referrals.
The overall diagnostic accuracy was slightly lower than predicted by the manufacturer or from previous studies.
This information should be considered by referring clinicians when determining indications for an ILR and will hopefully lead to more appropriate requests for implantation and so help to reduce costs and time spent analysing traces.
Graph showing the total number of ILRs requested by grade of doctor for 3 arrhythmia categories (bradyarrhythmia, tachyarrhythmia and cryptogenic stroke) compared with the total number of arrhythmias diagnosed
Conflict of Interest None