Hi! minty.........just got back.
Yes i quite understand your concern now that you have explained the situation with your husband.
Your EHBs have been fully investigated and this is not an uncommon situation where the cause is not known.The good news is, that you stand no better or worse chance of developing a stroke or heart attack than someone who doesn't suffer from EHBs.
The next stage would be a pace maker, but in my opinion that would be a bit over the top considering the mild symptoms that you are having.
You mention bisoprolol as a likely culprit and that sounds a good shout, I presume that you are on 2.5mgms twice daily. It might be worth asking your GP if you can reduce the dose, but only if you are taking two daily.
That is the best i can do...;-)