Anterior mitral valve leaflet length in cats with hypertrophic cardiomyopathy.

Abstract

Introduction/Objectives: Anterior mitral valve leaflet (AMVL) elongation is a recognised feature of hypertrophic cardiomyopathy (HCM). However, whether AMVL elongation precedes left ventricular hypertrophy (LVH) in cats is currently unknown. The aim of this study was to explore the risk of developing an HCM phenotype in cats with an elongated AMVL. Animals, Materials and Methods: Retrospective longitudinal study. Apparently healthy cats with a normal baseline echocardiogram and a follow-up echocardiogram at >1 year were eligible. Cats at the baseline were grouped based on whether or not they developed HCM phenotype at follow-up. AMVL length and left atrial and left ventricular (LV) dimensions were measured from two-dimensional images. Results: 55 cats were enrolled with a median follow-up period of 5.4 years (25th and 75th quartile, 2.7-6.7). During this time, 17 cats (30.9%) developed an HCM phenotype. At baseline, cats that subsequently developed an HCM phenotype had greater AMVL length (9.4 mm [25th and 75th quartile, 9.0-10.6] vs 8.5 mm [25th and 75th quartile, 7.6-9.1], p < 0.0001) and maximal LV wall thickness (4.5 mm [25th and 75th quartile, 4.1-4.7] vs 4.0 mm [25th and 75th quartile, 3.7-4.6], p = 0.007) than those that did not. Multiple logistic regression analysis confirmed that both baseline variables were independent predictors for development of an HCM phenotype. Conclusions: The AMVL length was greater in cats that subsequently developed LVH. Further studies investigating the clinical application of AMVL in the natural history of feline HCM are warranted.