Just for the record I have some knowledge of pacemakers.
Thye all react to a magnetic field. This is deliberate. When you went for for a pacemaker check they used to put a magnet on the pacemaker . This automatically puts it into a fixed rate of 100 bpm. This was a test it is also an emergency baleout if the pacemaker goes nuts. When they operateon someone with a pacemaker they keep a magnet nearby in case they need to override the pacemaker in some situations.
They flip back to normal once out of the magnetic field. It is not a good idea unless you know what you are doing as Steptoe noted above it is scary.
The US army has done some work on EMP and pacemakers and it is not clear that they would be damaged.
Jurys out and hopefully will never need to come in!
Appin