Is It Safe To Take Lisinopril To Strengthen Heart Muscles?

My doctor told me I have a weak heart and that there is no way to strengthen it. Exercise does not strengthen the heart he said. He prescribed lisinopril and said that it can help to strengthen the heart. I want to reverse this heart weakness! What can I do? I m 59 years old female 316# have fibromyalgia, hypertension and back pain that are treated with lyrica, cymbalta, Mobic, clonodine and now lisinopril.