An<unk>  (ILR), also known as an insertable cardiac monitor (ICM), is a small device about the size of a pack of chewing gum or USB memory stick that is implanted just under the skin of the chest for cardiac monitoring (that is, to record the heart's electrical activity).
Implantable loop recorder
Transcutaneous pacing
Heart rate monitor
Cardiac pacemaker
Automated external defibrillator
Microcurrent electrical neuromuscular stimulator
Biological pacemaker
Holter monitor