OBJECTIVES

The identification of atrial fibrillation (AF) in cryptogenic stroke (CS) patients provides an opportunity to reduce risk of stroke recurrence with anticoagulants.

The review assessed the diagnostic test accuracy (DTA) and clinical effectiveness of three implantable cardiac monitors (ICMs: BioMonitor 2-AF™, Confirm RX™, and Reveal LINQ™) compared with standard care (no further ECG monitoring) to detect AF in patients with CS after 24 hours of external ECG monitoring.

METHODS

A systematic review (PROSPERO number CRD42018109216) of MEDLINE, EMBASE, CENTRAL, DARE and HTA databases from inception until September 2018. Two reviewers agreed studies for inclusion and performed RCT quality assessment with the Cochrane risk of bias 2 tool.

RESULTS

One randomised controlled trial comparing an older version of the Reveal LINQ (CRYSTAL-AF), twenty-six non-comparative observational studies of ICM (none studied BioMonitor 2-AF or Confirm RX) and no DTA studies were included. Data were presented narratively as there were insufficient data for synthesis.

The rate of AF detection was significantly higher with the Reveal XT compared with standard care (36 months hazard ratio 8.8, 95% confidence interval: 3.5 to 22.2, p<0.001). However, the 26 non-comparative studies demonstrated AF detection rates are highly variable although there was substantial clinical heterogeneity (e.g. different stroke severity). Nevertheless, most AF detected was asymptomatic and therefore would be unlikely to have been picked up without an ICM.

Device-related adverse events (AEs) such as pain and infection were low in all studies considered.

CONCLUSIONS

Reveal LINQ may be more effective in detecting AF than standard care in CS patients and device-related AEs are rare with ICMs. There are insufficient clinical data in a CS population to assess Confirm RX or BioMonitor 2-AF with standard care. High quality RCTs are needed to confirm the comparative efficacy of the different ICMs in CS patients.