I have been on 25mg of Atenolol for two years now and I do notice...

I to have had severe leg cramping and toe numbness and my heart seems to just go off on it's own. The doctors have tested me in so many ways and nothing. So they upped my doese of Atenelol and the symptoms got worse, I am now weened off the Atenelol and was placed on Diovan. I would contact your doctor and talk to them about switching to something else.
I find that now my blood pressure is actually better with out the Atenelol most days. I hope everyone here gets the answers they need to get control of their lives back.