Dilated cardiomyopathy in juvenile doberman pinschers.

BACKGROUND

Canine dilated cardiomyopathy (DCM) is an acquired heart muscle disease of unknown etiology characterized by commonly adult onset of arrhythmias, congestive heart failure(CHF), and sudden death. Myocardial failure associated with myocarditis has been well documented in puppies infected with parvovirus. While a form of DCM has recently been described in juvenile Portuguese Water Dogs it has not been reported in juvenile Doberman pinschers, a breed known for its high prevalence of DCM.

METHODS

We examined 7 Doberman pinscher puppies that were referred for cardiovascular examination. Six were from a litter of 8 (2 of the 8 died earlier with congestive heart failure) and an additional puppy was from an unrelated litter. Clinical assessment included physical examination, electrocardiography and echocardiography. Autopsy was performed on 3 puppies from the same litter with echocardiographic documented DCM. Cardiac tissues were evaluated histologically and by PCR analysis for parvovirus.

RESULTS

In the litter of 8 puppies, 6 were affected with DCM between 10 days and 4 weeks of age. Of these 6 dogs, 2 died with acute pulmonary edema; 3 were euthanized at 4 weeks of age due to an advanced stage of DCM; 1 was diagnosed with DCM at 11 weeks of age. The latter survived for 2.5 years until it developed CHF and was euthanized. The remaining 2 dogs were unaffected and survived to adulthood. Another puppy from an unrelated litter developed DCM and CHF at 13 weeks of age, and was euthanized 4 weeks later. PCR analysis performed on myocardial tissue was negative for parvovirus genome. Cardiac histopathology revealed extensive myocytolysis involving myocytes and conduction fibers, hyperplasia of myocytes and smooth muscle cells, and attenuated myocytes separated by extracellular edematous ground substance ("wavy fibers").

CONCLUSIONS

A juvenile form of DCM with high morbidity was detected in 6 Doberman pinscher puppies from one litter and in a puppy from an unrelated litter. Congestive heart failure occurred in most of the affected puppies between 10 days and 17 weeks of age.