An Engineering Perspective of External Cardiac Loop Recorder: A Systematic Review

Table 1

Comparison among Holter monitor, ELR, and ILR.

	Advantages	Limitations	Indications	Diagnostic yield
Holter monitor	Low cost, continuous monitoring	Short duration of monitoring with low diagnostic yield	Patients with very frequent symptoms (≥1 week)	6–22%
External loop recorder	Retrospective and prospective ECG records, possibility to record asymptomatic arrhythmias automatically	Poor recordings, poor patient compliance to wearing device, continuous device maintenance required	Compliant patients with intersymptom interval ≤ 4 weeks	24–47%
Implantable loop recorder	Prolonged monitoring without external electrodes, highest diagnostic yield	Invasive implantation with risk of local complications, high cost	Early phase of evaluation of patients with recurrent syncope of uncertain origin that have absence of high risk criteria that require immediate hospitalization or intensive evaluation and a likely recurrence within device battery longevity	43–78%