Those are serious conditions indeed. Unfortunately, the medications prescribed for both conditions can end up having serious side effects with long term use. Prescription medications often deplete vital nutrients from the body, leading to the side effects. One of the important elements lost from the body due to sever blood pressure medications is called Coenzyme Q10 and it is vital to cardiac health. Supplementing with it can help you reduce effects of over medication. A good quality Vitamin B complex can also help.
When it comes to lowering blood pressure normally, L-Arginine is a dietary supplement that can help. You can also use supplements like Vitamin C to improve the health of the arteries. Foods like aged garlic can also help reduce blood pressure. Making sure that you use the right kind of salt in your diet (sea salt, not table salt loaded with sodium) and getting moderate exercise can also help you move the needle on your blood pressure issues in a big way.
Just remember: when you are on medications, changing your diet and lifestyle for the better is a great step to take on your own. However, when introducing dietary supplements alongside medications, you should keep your medical practitioner involved.