Propranolol (Inderal), was the first beta blocker used in the US for hypertension. Soon its CNS side effects, spurred chemical cousins called cardioselective beta blockers, (Tenormin (atenolol) is one), to be developed.

Propranolol today is used for migraine prophylaxis and some doctors are trying it for PTSD. Some use it for performance anxiety, but atenolol is usually used instead because it is less
sedating. In high doses propranolol can cause forgetfulness and or depressive symptoms.

http://www.nimh.nih.gov/health/publi...et/index.shtml

Propranolol is still used but infrequently for cardiac issues (angina) and hypertension. If you remain on this for a while, you may need a taper, to discontinue, with doctor supervision.
The rapid heart beat that occurs during discontinuance should be avoided as much as possible.

This is not a really high dose. You will probably not get much in the way of cardiac side effects at this low dose, unless you have some undiagnosed cardiac issue hiding.

http://www.drugs.com/propranolol.html