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6-month history of decreasing activity and reluctance to go on walks. The owner reported that while at home the dog seemed fine but refused to walk more than ½ block. The dog's appetite was normal and there was a history chronic low grade coughing.


9-year-old male neutered Shih Tzu


6-month history of decreasing activity and reluctance to go on walks. The owner reported that while at home the dog seemed fine but refused to walk more than ½ block. The dog's appetite was normal and there was a history chronic low grade coughing.


Weight = 20.5 lbs
Temp = 100.2 ºF
Heat Rate = 140
Respiration = panting

The dog was moderately overweight at the time of examination. On chest auscultation, there was a moderate systolic heart murmur (grade 3-4/6) loudest on the left side but also prominent on the right side of the chest. Abdominal palpation was normal. The dog was sensitive to palpation of his spine in the lumbar region and had decreased range of motion in both his hips.


Exercise intolerance
Heart Murmur
Pain on palpation of back and hips


Degenerative intervertebral disc disease
Congestive Heart Failure
Chronic respiratory disease
Metabolic diseases such as kidney failure, hypothyroidism, poor adrenal function


Because any one of the above differentials could explain the presenting signs, initial diagnostics included a complete blood panel to rule out metabolic diseases and chest and back radiographs to assess for disc disease, arthritis and congestive heart failure.


The blood panel showed a mild elevation in the white blood cell count with monocytosis- cells typically associated with chronic infection or inflammation. The radiographs revealed an enlarged heart and moderately enlarged liver. There were multiple areas of arthritis in the spine and the hips had evidence of mild degenerative joint disease.


The owner was advised of the results of the initial work up and told that the reluctance to exercise could be due to either the arthritis and disc disease or to < lugins/editors/tinymce/jscripts/tiny_mce/themes/advanced/langs/en.js" type="text/javascript"> script src="/plugins/editors/tinymce/jscripts/tiny_mce/themes/advanced/langs/en.js" type="text/javascript"> heart problems. a trial course of a non-steroidal anti-inflammatory was implemented and an echocardiogram was scheduled for the following week to better assess the heart condition.


The dog was returned to the clinic the following week. The owner reported that she had noticed no change in the dog's willingness to walk despite the anti-inflammatory, suggesting that the dog's reluctance to exercise was not a pain-related issue.

An echocardiogram of the dog revealed severe valvular insufficiency of both the mitral and tricuspid valves with right heart enlargement and pulmonary hypertension.

After consultation with a cardiologist, we placed the dog on a low sodium diet (Hill's h/d) and enalapril and advised the owner to return in 3 weeks for a recheck.

Unfortunately, the owner called two days later to report that the dog had collapsed the previous night in the back yard and died on route to the emergency clinic.


Exercise intolerance is a common complaint in older pets and can have many different causes. This case illustrates the importance of a thorough physical examination and diagnostic work up in determining the underlying cause for a rather nebulous symptom. The case also illustrates the importance of early diagnosis and intervention in heart disease. This dog's sudden death was most likely due either to the formation of a blood clot in the heart that subsequently embolised or to an acute myocardial infarction.

While heart disease is most often diagnosed in middle-aged to older pets, congenital heart problems are well documented. In the early stages, heart disease is usually symptomatic. In sedentary pets, especially cats, heart disease must be quite advanced before noticeable signs develop. Common signs of heart disease include exercise intolerance, unwillingness to perform normal activities and coughing. Regular physical examinations will insure the heart and other problems are detected early when they are most treatable. Long before you notice a change in your pet's behavior, we will hear a difference in the heart.

For more information on the diagnosis and treatment of heart disease, go to our client education handout on cardiology.

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