Dogs usually like the doggie toothpaste better.
As for the heart murmur
, the treatment depends on exactly what type of heart
defect is causing the murmur
. Since your vet predicted that the dog would start coughing, and the dog has in fact started coughing, I take it that it is not a benign murmur. In my nonprofessional opinion, most likely the murmur is due to valve disease, and the cough is a symptom of congestive heart failure.