Propranolol Arm: Subjects who qualify for this subgroup will be given propranolol 10 mg three times per day. If they tolerate the medication well with no side effects, after 5 days, they will then increase the dose to 20 mg three times per day. If they tolerate the 20 mg dose well with no side effects, after another 5 days (day 10), they will then increase the dose to 40 mg three times per day and stay on this for the duration of the study.