I'm sorry your dog is having troubles. I've got some questions for you:
-is she on heartworm prevention?
-when was her last thyroid check (bloodwork to check her T4 level)?
-when was her last bloodwork to check phenobarb level?
-has your vet taken any xrays or run any other bloodwork?
-how is her appetite?
Hi again and thank you for the other information,
That post was not my answer. It was just an information request. There is a limit to how much I can do over the Internet, and the more information I have, the more I can try to help you.
This post is also not an answer. It is another information request because I still have questions so that I can get a better idea of what is going on, because the symptoms you've described can be due to many, many different things going on.
Has your dog been spayed or she she still intact?
Has your vet taken any chest x-rays of your dog recently? Has he made sure her heart is functioning properly with an ECG or ultrasound (echocardiogram) of the heart?
Owners know their pets best. If you are concerned about her breathing, I believe further diagnostics should be done for her heart and lungs (both heart and lungs because the heart can so easily affect the lungs). She needs further diagnostics because I don't think you will get your answer for what is going on with her without having more done. By further diagnostics, I mean the following:
1) 3-view chest radiographs: this means that one x-ray is taken of her chest with her in each of three positions: laying on right side, on her back, and on her left side. This is the only way to 100% thoroughly evaluate a dog's chest. Many vets (myself included) are limited in how much they can do because the client can only afford so much, and x-rays are expensive. So often we are limited to being only able to take 2 xrays of the chest (one from the side, the other with the dog laying on his or her back). But the absolute best is to take all three views, when financially possible. The reasoning for this is that when you are looking for very important and subtle changes to check for any type of disease, there are areas of the lungs and heart that are best evaluated with each view. Taking only one or two views leaves some areas unevaluated, therefore the possibility still exists in those areas that there is disease going on that you miss.
X-rays are used to evaluate heart size and shape, the size and shape of the heart and lung vessels, the bronchi and bronchioles in the lungs, and the surrounding lung tissue. We use them to check for diseases such as cardiomyopathy (problem with the heart muscle, which usually shows up as the heart being too big), valve problems in the heart (also shows up as enlargement in certain areas of the heart), thickening of the bronchi or bronchioles (which could indicate some type of obstructive pulmonary disease or allergy), tumors (hate to mention this but must be on the list), fungal or bacterial pneumonias, fluid in the lungs, or problems with the trachea (breathing tube). All of the things I just listed can cause labored breathing.
2) ECG and/or ultrasound of the heart: If there were to be any abnormalities found on the xray concerning her heart, the next step would be to perform an ECG on her heart to make sure it is functioning correctly. An ECG is a printout of the electrical nervous activity going through the heart that keeps it beating. There is a very specific and repetitious way that the nerve signal flows through the heart to keep it beating, and any changes in this will show up on the printout and can be evaluated. Certain types of changes can pinpoint specific problems with the heart, for example, a wide QRS complex (the waves on the printout) can indicate that the heart is too large.
An ultrasound of the heart should be the next step if the ECG is abnormal. An ultrasound of the heart is just like ultrasound of anything else, it will show it real-time on a screen as it beats. The key to this, though, is that an *experienced* cardiologist is the best person to evaluate a dog's cardiac ultrasound because of how complicated it can be to make sure that you are viewing the correct spot on the heart with the ultrasound probe.
3) Abdominal x-rays would be a good idea, too, because sometimes heavy breathing can be due to something in the abdomen pressing on the lungs. For example, an enlarged liver, or fluid in the abdomen, can press on the lungs and make breathing more difficult. One or two views of the abdomen is sufficient to evaluate this.
4) Complete bloodwork (including a heartworm test) is never a bad idea. This is another way to evaluate most of the body's functions and can give more clues as to what is going on. I know you said that Becky is on heartworm prevention. I would still very strongly recommend that she be tested for heartworms (unless she has been tested in the past 6 months) because it is very easy to test for and can cause the exact symptoms you describe.
If your current vet will not do any more for Becky, you should consider finding another vet who is willing to address her breathing problem. Please re-read this answer again, and think of any and all questions you may have. You can always ask me more by replying to this answer. I am sure you will have more questions, because I know this was a lot of information. And I may not have answered your question thoroughly. If not, please let me know. I will help you until you are completely satisfied.
Hi and thank you for your update!
Most cardiologists will require a referral from another vet who has examined your dog, so usually you can't go directly to them without having your regular vet call them first. Your current vet may do this for you, but also if you end up seeing another vet, that vet could refer you as well (but would have to examine your dog first).
Yes, you are proceeding in the right direction by talking to your vet first, and telling her that although Becky's heart may sound normal, you are still worried and would like further diagnostics for her heart and lungs, if she could do them. Your current vet may be correct in that Becky's heart and lungs are normal, but x-rays are a good next step to help prove that the heart and lungs are normal. The reason I happen to be adamant about this is that I have been proven wrong before regarding lungs and heart (I once examined a cat, and believed its heart and lungs to be normal, but then one week later, on x-ray, discovered he had a large lung tumor).
In no way do I mean to imply that I believe Becky has a tumor, nor do I mean to imply that your current vet is missing something. I don't think that doing more to look into the problem will hurt, though, and you very well may find an answer.
Again, keep asking me questions if you have them! I'm happy to keep giving my input!