Acta Veterinaria Scandinavica Research Prevalence of myocardial hypertrophy in a population of asymptomatic Swedish Maine coon cats Suzanne Gundler*1, Anna Tidholm2 and Jens Häggström3 BioMed Central Open Access Address: 1Bagarmossen Animal Hospital, Ljusnevägen 17, S-128 48 Bagarmossen, Sweden, 2Albano Animal Hospital, Rinkebyvägen 23, S-182 36 Danderyd, Sweden and 3Department of Physiology, Faculty of Veterinary Medicine, Swedish University of Agricultural Science, PO box 7018, Uppsala, Sweden Email: Suzanne Gundler* - suzanne.gundler@djursjukhus-sthlm.se; Anna Tidholm - anna.tidholm@djursjukhus-sthlm.se; Jens Häggström - jens.haggstrom@kv.slu.se * Corresponding author Published: 18 June 2008 Acta Veterinaria Scandinavica 2008, 50:22 doi:10.1186/1751-0147-50-22 This article is available from: http://www.actavetscand.com/content/50/1/22 Received: 13 December 2007 Accepted: 18 June 2008 © 2008 Gundler et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: Maine 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. Methods: All 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. Results: Examinations 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. Conclusion: Depending 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. Background 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 met- abolic abnormalities which may cause myocardial hyper- trophy [2,3]. This disease has also been labeled idiopathic HCM, but because some of the underlying causes for Page 1 of 6 (page number not for citation purposes)