Pacemakers and ICDs are small electronic devices that are put into the chest or abdomen with leads, which are wires connecting the device to the heart. If your heartbeat becomes irregular, the device regularly delivers an electric impulse that travels through the lead to return your heartbeat to normal.
If you need your lead(s) and/or device(s) removed, a doctor who focuses on this type of procedure will choose the right device(s) to remove them.
Over time, the body naturally creates scar tissue that attaches the lead to the blood vessel walls and the heart. This scar tissue can be a problem during lead extraction procedures, which is why the doctors who focus on these procedures will need certain tools to do these procedures.
Reasons for a lead extraction include:
https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/lead-extraction
https://my.clevelandclinic.org/health/treatments/17165-lead-extraction