Utility and limitations of long-term monitoring of atrial fibrillation using an implantable loop recorder

Atrial fibrillation (AF) is the most common cardiac arrhythmia diagnosed and treated in the world. The treatment of patients' symptoms as well as the prevention of stroke and heart failure is dependent on accurate detection and characterization of AF. A variety of electrocardiographic (ECG) monitoring techniques are being used for these purposes. However, these intermittent ECG monitoring techniques have been shown to underdiagnose AF events while having limited ability to characterize AF burden and density. Continuous long-term implantable loop recorder (ILR)-based ECG monitoring has been designed to overcome these limitations. This technology is being increasingly used to diagnose episodes of AF in high-risk patients and to improve characterization of AF episodes in patients with known AF. This review aims to review the potential clinical utility of ILR-based ECG monitoring while highlighting some inherent limitations of the current technology. An understanding of these limitations is important when considering the use of ILR-based ECG monitoring and clinical decision making based on the information being stored within these devices.