Under normal circumstances, you can expect the following:

• Medicine may be given to you to help you relax.
• A local anesthetic will be given on the skin in the area of implantation to numb it.
• Your doctor will make a small incision in your skin. This is usually done in the left upper chest.
• A small pocket is created under your skin. He or she will place the loop recorder in this pocket. 
• The device is about the size of a flat AA battery.
• Your incision will be closed with sutures. A bandage will be put over the area.

Reference: Loop Recorder Implantation. (n.d.). Retrieved from https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/loop-recorder-implantation