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02-08-2011 | Article

Hypertrophic cardiomyopathy affects 1 in 10 British Shorthairs


Free abstract

MedWire News: Hypertrophic cardiomyopathy (HCM) is highly prevalent among British Shorthair (BSH) cats, with males being particularly prone to the condition, research shows.

The team that conducted the research recommends the use of echocardiographic screening in BSH cats, especially animals used for breeding and those with a family history of heart disease.

HCM is the most commonly diagnosed cardiac disorder in cats and is characterized by left ventricular hypertrophy and diastolic dysfunction. The epidemiology of HCM is well-characterized in some breeds, such as the Maine Coon and Ragdoll, whereas less is known about the prevalence of the condition in domestic BSH cats.

To investigate, Sara Granström (University of Copenhagen, Denmark) and co-workers undertook a prospective cross-sectional study involving 329 BSH cats who underwent routine echocardiographic screening over a 4-year period.

All cats were examined by the same two trained ultrasonographers using a screening protocol of the left ventricle (LV) in right parasternal long-axis and short-axis views.

In all, 28 cats (8.5%) were classified as HCM-positive, 14 (4.3%) as HCM-equivocal, and 282 (85.7%) as HCM-negative. Five cats (1.5%) were diagnosed with another cardiac disease.

Of the 28 cats with definite HCM, 82.1% were male, giving a prevalence of 20.0% among males and 2.3% among females.

The median age at diagnosis was 2.7 years in both males and females, although the youngest case was just 10 months old. Nearly two-thirds of cats with HCM had a family history of the condition, most often in a parent, and sire-to-offspring was the most common route of inheritance.

Detailed examination of the cats with HCM revealed that three-quarters had symmetric hypertrophy affecting the entire LV while the remainder had either asymmetric or regional changes. In addition, nearly ninety percent of the cats with HCM had systolic anterior motion of the mitral valve.

Finally, logistic regression analysis showed that gender but not age was a significant independent risk factor for HCM, with an adjusted odds ratio of 7.89 for male versus female cats.

Writing in the Journal of Veterinary Internal Medicine, Granström and co-authors note that their reported prevalence may represent an underestimation, because of the skewed sex distribution of the sample.

They conclude: "Even with the previously discussed epidemiological reservations, we believe that the prevalence of HCM in our cohort may provide a reasonable estimate of the frequency of HCM within the breed.

"Based on our results, we strongly recommend echocardiographic screening in BSH, especially in cats used for breeding or with a family history of heart disease."

By Joanna Lyford