dog panting

Question
My golden retriever is twelve and has been panting continually for the past year.  I have taken her to the vet many times and they find nothing wrong.  She pants very heavily even when it is cool out.  Do you know of any reasons for this.  She takes a thyroid pill twice daily and has a slight heart murmur which they just found.  Otherwise she is in excellent health.

Answer
Dogs will pant when excited or to cool themselves off.  Some dogs will also pant more with certain disease conditions such as Cushing's Disease or enlarged liver.  I would recommend a complete chemistry screen and recheck her thyroid level as her thyroid medication could be too high.  Otherwise, I would recommend a chest x-ray.