Of course you can. Beta Blockers just help to slow the heart.
As far as your doctor's diagnosis, I would still be suspicious of an electrical problem. They are impossible to find unless you are on a monitor while one is occurring. Doctors are too often likely to jump to the "anxiety" answer simply because they have not seen the heart malfunctioning. ECGs would only be able to tell him if you have a prolapse causing an arrhythmia
. Even an EKG would only show a problem during an arrhythmia. Anxiety is just too easy of a diagnosis to make when they can't find anything else.
Anyway, beta blockers are an acceptable treatment for some electrical issues too, so you might find yourself doing well on them.