One of my pups now passed was diagnosed with enlarge heart at age 9 years old, also coughed so much I didn't know how she could breathe. I cannot say what meds she was given, this was in 2005. By baby lived a healthy with meds until she was 13 years old. Her cause of death was not related to her heart. Keep the faith, there are meds that will help Teddy live a better life.
prayers going out for lil Teddy.