Implantable loop recorders (ILR) are used for long-term arrhythmia monitoring inpatients that have had syncope or cryptogenic strokes (possible from atrial fibrillation).  There are two primary models of loop recorders: St. Jude Medical’s Confirm (http://www.sjmprofessional.com/Products/US/Implantable-Cardiac-Diagnostics/SJM-Confirm-Implantable-Cardiac-Monitor.aspx) and Medtronic’s Reveal (http://www.medtronic.com/for-healthcare-professionals/products-therapies/cardiac-rhythm/cardiac-monitors-insert/reveal-dx-and-reveal-xt-insertable-cardiac-monitors-icms/index.htm).

ILR are placed just under the skin in the left chest and are able to record a patient’s heart rhythm.  It helps to diagnose the cause of syncope (fainting) or any number of heart rhythm disorders.  Initially, doctors try to diagnose heart rhythm disorders with monitors that are worn for 48hours to 2-4weeks; however, an arrhythmia that may only occur every few months will not be detected by a brief snapshot in a patient’s life.  ILR generally last 2-3 years before the battery wears out.

The exciting future of implantable monitors is not simply heart rhythm diagnosis.  Recently, the company MicroCHIPS announced results of the first human clinical trial of an implantable, wireless microchip drug delivery device (http://www.mchips.com/technology.html).  This type of implantable device can allow automated drug delivery over a period of several years.  One can imagine a device that can track a person’s heart rate and dose medication to permit precise control of heart during an abnormal heart rhythm.