Please address this issue with the dog's vet. However, indeed, as in humans, this most likely represent severe mitral regurgitation that at this point needs to be treated with afterload reduction and diuretics.
Did you really mean to post a question about a dog on the Cardiology / Heart Disease Expert forum? There is a forum for pet questions, this forum is for prople that need advice from a cardiologist. Don't get me wrong, I have two toy poodles that are my world and mean everything to me and since my kids married and moved out they have replaced them as the "kids" in the family, I just don't think you'll get the answers you're looking for here. You should try the pet forum under the forum icon. I don't want to speak for the doctors, but I don't know if they will feel qualified to answer such a question
Good luck!