I have been a paramedic for 14 years. While that does not make me a pacemaker expert, I have quite a bit of experience dealing with them.
I have also been a ham radio operator for 16 years. A hobby that REALLY generates some strong RF fields. Much MUCH higher than that of a metal detector. In this hobby, I have met a number of operators who have pacemakers. Never any problems with them at all.
Modern pacemakers are quite resistant to RF and other forms of radiated energy fields. For example, you don't see warning signs on the sides of microwaves anymore, advising those with pacemakers to stay away. As an American, you constantly drive by cell towers, radio station transmitting antennas, ham radio operators in vehicles, electronics stores, microwaves, ETC.
The only real damage I have seen a pacemaker sustain was during a CPR situation where we had to us a defibrillator once. The pacemaker in question was a first generation type over 20 years old (at the time. this event was a decade ago). After delivering the shocks, the pacemaker began making a sizzling noise that we could hear inside the patients skin. It became VERY hot to touch. The ER doctor actually made an incision and moved the pacemaker so that it was external to the skin, where it continued to melt down. Unfortunately, the patient did not survive the event.
Other than that situation, I have defibrillated hundreds of people (many living and awake, eg: Synchronized cardioversion, Trans cutaneous pacing, etc) with pacemakers, and they didn't suffer any damage. That is perhaps the most direct form of introducing energy to a pacemaker that I can think of.
While all of my evidence in anecdotal, I would personally feel comfortable using a metal detector or allowing a family member to use a detector if either of us had a pacemaker installed.
THAT SAID, there is no replacement for asking your doctor. That should be the final answer, not a bunch of random schmucks on a website
73,
WM