Do stents interfere with the alarm system in stores?

I have 3 stents in my heart. Whenever I go to a certain store, their beeper goes off. This also happens when I leave the store. My doctor doesn't know why this happens. Please advise.

 

Stents do not contain any metal that would activate a store exit alarm system or an entry point metal sensor. You may have a pacemaker in place with a battery that could set off alarm systems, or you may have a hospital identity smart card that could be in your pocket or the wallet.