Lbbb
As the condition is permanent, I was told that the restriction on my Class 1 is also permanent, but this isn't a problem if you only fly multi-crew equipment.
As for lifestyle, I was only advised to do the normal commonsense stuff (i.e. Don't smoke, Drink with moderation, Eat sensibly and don't get overweight, and Exercise regularly).
As there are no physical symptoms, it dosen't really affect anything I do, and I have never been advised to restrict my pulse rate, which the CAA push up to 190 every year on the treadmill with no apparent ill effects!
Interestingly, you cannot hold a Heavy Goods Driving Licence if you have a Bundle Branch Block condition, but you can still fly an airliner.