The implantable loop recorder (ILR) is a subcutaneous, single - lead, electrocardiographic (ECG) monitoring device used for diagnosis in patients with recurrent unexplained episodes of palpitations or syncope, for long-term monitoring in patients at risk for or with documented atrial fibrillation (AF), and for risk stratification in patients who have sustained a myocardial infarction (MI) and those who have certain genetic disorders.
The device is typically implanted in the left parasternal region and is capable of storing ECG data automatically in response to a significant bradyarrhythmia or tachyarrhythmia or in response to patient activation. It is particularly useful either when symptoms are infrequent (and thus not amenable to diagnosis using short-term external ECG recording techniques) or when aggregate long-term data (eg, the burden of AF) are required.