Pacemaker is fine at 80BPM. But non-responsive if it drops to 70BPM

[ymcwhirr]

I'm hoping someone on here can offer me any suggestions. I had a pacemaker fitted a couple of months ago to resolve AF. Things are going well. Recovery making steady progress. However, I have one problem with it. It seems to run on two resting heart rates: 70 and 80. If it is going at 80, it's responsive, great in fact - the rate increases with exertion meaning I can enjoy an active lifestyle. But sometimes it drops to 70. I still feel fine, but if I try to do any exertion, it remains at 70. Which means I can't even walk up stairs without struggling. This happens daily, making it very hard to plan any sort of activity.

I'm due back into the clinic later this week; but the nurse I spoke to didn't seem too hopeful of resolving it. I'm only 43 - and usually have a very active, outdoor lifestyle.

Any information or experiences would be greatly appreciated.