Prevalence of myocardial hypertrophy in a population of asymptomatic Swedish Maine coon cats

Suzanne Gundler,Jens Häggström,Anna Tidholm

doi:10.1186/1751-0147-50-22

Suzanne Gundler, Jens Häggström + Show 1 more

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https://doi.org/10.1186/1751-0147-50-22

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Abstract

BackgroundMaine coon cats have a familial disposition for developing hypertrophic cardiomyopathy (HCM) with evidence of an autosomal dominant mode of inheritance [1]. The current mode to diagnose HCM is by use of echocardiography. However, definite reference criteria have not been established. The objective of the study was to determine the prevalence of echocardigraphic changes consistent with hypertrophic cardiomyopathy in Swedish Maine coon cats, and to compare echocardiographic measurements with previously published reference values.MethodsAll cats over the age of 8 months owned by breeders living in Stockholm, listed on the website of the Maine Coon breeders in Sweden by February 2001, were invited to participate in the study. Physical examination and M-mode and 2D echocardiographic examinations were performed in all cats.ResultsExaminations of 42 asymptomatic Maine coon cats (10 males and 32 females) were performed. The age of the cats ranged from 0,7 to 9,3 years with a mean of 4,8 ± 2,3 years. Four cats (9,5%) had a diastolic interventricular septal (IVSd) or left ventricular free wall (LVPWd) thickness exceeding 6,0 mm. In 3 of these cats the hypertrophy was segmental. Two cats (4,8%) had systolic anterior motion (SAM) of the mitral valve without concomitant hypertrophy. Five cats (11,9%) had IVSd or LVPWd exceeding 5,0 mm but less than 6,0 mm.ConclusionDepending on the reference values used, the prevalence of HCM in this study varied from 9,5% to 26,2%. Our study suggests that the left ventricular wall thickness of a normal cat is 5,0 mm or less, rather than 6,0 mm, previously used by most cardiologists. Appropriate echocardiographic reference values for Maine coon cats, and diagnostic criteria for HCM need to be further investigated.

Highlights

Maine coon cats have a familial disposition for developing hypertrophic cardiomyopathy (HCM) with evidence of an autosomal dominant mode of inheritance [1]
IVSd = Interventricular septal end-diastolic diameter left ventricular end diastolic diameter (LVIDd) = Left ventricular inner end-diastolic diameter LVWd = Left ventricular posterior wall end-diastolic diameter IVSs = Inter ventricular septal systolic diameter LVIDs = Left ventricular inner systolic diameter LVWs = Left ventricular posterior wall systolic diameter FS = Fractional shortening AO-M-mode = Aortic end-diastolic diameter measured on M-mode LA-M-mode = Left atrial end-systolic diameter measured on M-mode AO-2D = Aortic end-diastolic diameter measured on 2D LA-2D = Left atrial end-diastolic diameter measured on 2D
Using a reference value of ≥ 6 mm for the left ventricular wall, we found that in the present study 4 (9,5%) cats were definitively diagnosed with HCM, and two additional cats with systolic anterior motion (SAM) were suspected of having the disease, which added together makes 14,3% of this population

Summary

Introduction

Maine coon cats have a familial disposition for developing hypertrophic cardiomyopathy (HCM) with evidence of an autosomal dominant mode of inheritance [1]. The objective of the study was to determine the prevalence of echocardigraphic changes consistent with hypertrophic cardiomyopathy in Swedish Maine coon cats, and to compare echocardiographic measurements with previously published reference values. Primary HCM is characterised by concentric myocardial hypertrophy, i.e. increased wall thickness with normal or decreased chamber inner dimensions, primarily of the left ventricle, in the absence of other cardiac, systemic or metabolic abnormalities which may cause myocardial hypertrophy [2,3]. This disease has been labeled idiopathic HCM, but because some of the underlying causes for (page number not for citation purposes). Because M-mode echocardiograms obtained from the standard view for measuring the left ventricular dimensions, just below the mitral valve leaflets, can miss localized hypertrophy, assessment of ventricular dimensions should be made from both two-dimensional (2D), sweeping from base to apex, and from M-mode [1,2,3]

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