Loop recorder placement (or implantation) is a minor surgical procedure to place a type of heart recording or monitoring device called an implantable loop recorder (ILR) underneath the skin of your chest, overlying the heart. The device functions as an electrocardiogram (ECG), continuously recording electrical activity from your heart for up to 3 years. This can assist in detecting abnormal heart rhythms that can trigger a variety of problems such as syncope (fainting).