Haven't been on here in months and saw this. Last open heart surgery I had (2000) they needed to put in a pacemaker/defibrilator. Battery only lasted 5 years but that was because of the defibrillator so they had to replace it. The pacing you don't feel and like others have said the only bad thing is the bulge by the left shoulder. I slip my shoulder harness while in the car behing my back as my second one seemed to be bothered by it where my first didn't. Ask the doctor but he may be limited if working over the engine of a car (I think they just say that as a disclaimer as I've never had a problem). Also make sure you let them know if going through any type of a metal detector or you'll have several uniformed gentlemen around you VERY FAST, lol. Again, the pacing he shouldn't feel but the defibrillator (slows the heart if it goes over a set heart rate, mine is 179 bpm, will give a...how shall I say... awakening to you as it is basically like the ones you see on tv where they use the paddles. He'll be fine with it, it's just the idea and the not knowing that worries you but as said, the doctors know exactly what they are doing and it is very routine. By the way, in both cases I never had to use a sling, just watch lifting for a bit.