Hey grayhenry!
I'm glad you're following your doctor's recommendations. Have you asked your doctor about losing weight? Did he or she have any information? You could get a referral to a dietitian, I would think.
You don't mention anything about food or having a food plan, like counting your calories, so it's hard to make any suggestions. Of course, we're not doctors here, so we can't give medical advice. You'd want to check with your doc about any changes to your eating. I'd say that getting enough protein is very important.
Walking is a good thing--but because of the beta blocker, you'd need to be careful that you don't try to go too fast or walk when it's too hot.
Some studies have shown that a supplement called Coenzyme Q10 can be helpful for your condition. You might want to check it out.
Glad to see you here! Please keep coming around and posting.
Jay