Hypertrophic cardiomyopathy in a litter of five mixed-breed cats.

A litter of five, 18-month-old, mixed-breed cats were determined to have hypertrophic cardiomyopathy (HCM). Although no overt clinical signs were present in any cat, systolic heart murmurs were present in each. Electrocardiograms were normal, while subjective interpretations of heart enlargement on radiographs were made on four cats. Echocardiographic analyses indicated abnormalities consistent with HCM. Overt clinical signs are absent two years following diagnosis.