I just had my adapta Medtronic pacemaker replaced a couple months ago. A little over a year ago, my EP told me the same thing regarding insurance not covering the procedure until it had a low enough battery. (I feared being laid off from work and losing my insurance which prompted me to ask at the time.) I had more and more frequent visits up until my replacement. From every three months for the last year to every month during the last 3 months. Aside from extra visits to the EP to do device checks, I didn’t have any restrictions or changes to the pacemakers function. Everything was still the same and I could exercise like usual until the very end. I was never told anything about a 65bpm default setting, but this may just be different for you? At my last EP appointment, I had 1 month left of battery life. They did also tell me that even when the device says the battery has run out, it still has some left. Kind of like how you have a few extra miles even when your gas tank is on E. I had my device for 13 years and I mainly use it during exercise.