Canine idiopathic dilated cardiomyopathy. Part I: Aetiology, clinical characteristics, epidemiology and pathology

Area of Science:

• Veterinary Cardiology
• Canine Pathology
• Animal Cardiology

Background:

• Dilated cardiomyopathy (DCM) is a prevalent heart disease in dogs, marked by chamber dilation and impaired heart muscle function.
• The exact cause of DCM is often unknown, with potential factors including genetics, nutrition, inflammation, infection, or toxin exposure.
• While often considered breed-specific, DCM in dogs exhibits distinct histological patterns.

Purpose of the Study:

• To review and classify histopathologic findings in canine dilated cardiomyopathy.
• To compare the efficacy of histological classification versus breed-specific syndromes for diagnosing canine DCM.
• To highlight the diagnostic challenges and poor prognosis associated with canine DCM.

Main Methods:

• Review of histopathologic findings in canine dilated cardiomyopathy cases.
• Classification of canine DCM based on distinct histological patterns.
• Comparison of histological findings with known breed predispositions.

Main Results:

• Two distinct histological forms of canine DCM were identified: "fatty infiltration-degenerative" and "attenuated wavy fiber."
• The "fatty infiltration-degenerative" type is associated with Boxers and Doberman Pinschers.
• The "attenuated wavy fiber" type is observed in various large and medium-sized breeds, including some Boxers and Doberman Pinschers.

Conclusions:

• Histological classification of canine DCM is superior to breed-specific syndromes, as some breeds can exhibit both forms.
• Ante-mortem diagnosis of the specific cause of DCM in dogs remains challenging.
• Canine DCM carries a poor prognosis, with limited identified prognostic indicators.