Overview

Hypertrophic cardiomyopathy (HCM) is an acquired idiopathic myocardial disorder characterized by concentric hypertrophy and resultant diastolic dysfunction of primarily the left ventricle. It is the most common type of cardiomyopathy in cats.

The majority of cases are idiopathic, that is, the primary etiology is unknown. Like in humans, a familial and heritable form of HCM has been identified in certain feline breeds, including families of Maine Coons, Ragdolls, Persians, American Shorthairs, and British Shorthairs. The mode of inheritance in these breeds appears to be autosomal dominant. Breed-specific mutations of the myosin binding protein-C gene have been identified as causative of HCM in Maine Coons and Ragdolls. It is known, however, that there are other undiscovered genetic mutations since not all positive cases are linked to the above mutations.

While most cases are idiopathic, HCM may be secondary to other disorders such as:

• Systemic arterial hypertension
• Hyperthyroidism