yorkie fast breathing

Please help. Teddy is a 4+ year old yorkie. he has horrible dental issues and was taken to the vet two weeks ago with the issue of breathing very fast and elevated heart rate. He was put on lasix and enalaprin which helped him for the last two weeks as theDr said he has heart issues, but now he is having another breathing fast elevated heart rate issue. I need help. I cant let him suffer. I have limited funds, but I know God will make a way.