Proper diagnosis of any illness begins with a thorough physical examination and history, although other testing may be required for a definitive diagnosis. Diagnosing heart disease in a dog, whether the disease is related to valvular degeneration or another heart issue, is no different.
History and Physical Examination Findings in Dogs with Valvular Heart Disease
The basic history of any dog should include the age, sex, breed (or predominant breed) and body condition score. Historical factors such as age and breed can be important in diagnosing heart disease because valvular heart disease is more common in middle-aged and senior dogs and is also more common in small breed dogs, with some breeds having a higher incidence than others.
In addition the presence of symptoms such as coughing, exercise intolerance, respiratory difficulties, lack of appetite and other signs of illness should be noted. As an owner, being able to provide this information along with how long your dog has experienced the symptoms can be very helpful in establishing an accurate diagnosis.
Once an adequate history is obtained, your veterinarian should perform a thorough physical examination for your dog. The physical examination should include, among other things, evaluating the heart and lung sounds with the use of a stethoscope. This part of the examination may reveal a heart murmur or other abnormal sounds within the heart or the lungs.
Other findings that might be found in the physical examination of a dog with heart disease include ascites (fluid accumulation in the abdomen), cyanosis (blue or purple coloration of the gums indicating a lack of adequate oxygen saturation), swelling in the legs and similar symptoms characteristic of heart failure.
Radiographs (X-Rays) for Dogs with Heart Disease Resulting from Mitral or Tricuspid Valve Degeneration
Another important test your veterinarian is likely to recommend if there is suspicion of mitral or tricuspid valve disease or another type of heart disease is a series of radiographs (x-rays) of the chest.
Radiographs for dogs with mitral valve disease may reveal enlargement of the chambers of the left side of the heart. In dogs with tricuspid heart disease, enlargement of the right atrium and/or ventricle is more likely to be present.
Radiographs of the chest can also help determine whether there is evidence of congestive heart failure. In congestive heart failure, the lungs fill up will fluid and this will make the radiographic appearance of the lungs different than those of healthy lungs.
Blood Testing in Canine Degenerative Heart Valve Disease
Though there are unlikely to be specific changes in your dog's blood as a result of degenerative heart valve disease, your veterinarian will likely still recommend routine blood testing. This is done to rule out such things as heartworm disease (which can cause heart failure) and also to provide a baseline for evaluating the effect of medications administered in treating heart disease.
Routine blood testing should include a heartworm test, a complete blood cell count and a blood chemistry profile (including the measurement of blood electrolytes).
Evaluating Heart Valve Disease with an Echocardiogram
An echocardiogram is an ultrasonographic study of the heart. With an echocardiogram, it is actually possible to visualize the individual heart valves and see how much regurgitation is occurring as a result of leaky heart valves. In some cases, your veterinarian may recommend an echocardiogram as part of the diagnostic evaluation of your dog's heart disease.
Monitoring Dogs with Degenerative Valve Disease
Dogs diagnosed with degenerative heart valve disease need to monitored for progress or worsening of the disease. While your veterinarian will want to continue to monitor your dog with periodic examinations and radiographs of the chest, you should also monitor your dog at home.
Home monitoring of dogs with mitral or tricuspid disease should include:
- frequency of coughing
- sleeping respiratory rate (the number of breaths your dog takes in the course of a minute while sleeping)
- appetite
- general activity level
If your dog starts coughing more frequently, if the sleeping respiratory rate is greater than 30 breaths per minute, if your dog's appetite becomes depressed or he stops eating, if he becomes more lethargic or quieter than normal, or seems otherwise not himself, you should contact your veterinarian and have your dog examined.