It would be nice if your mom had a little plastic door that could be popped open and the old batteries
taken out and a new set of double A's dropped in. Such is not the case though, obviously. In fact "battery replacement" is a misnomer. In actuality, the entire pacemaker
is replaced. The leads from the heart are literally unplugged from the unit, the old unit is removed, and replaced by a completely new one loaded with a fresh battery.