Longitudinal assessment of systolic anterior motion of the mitral valve in cats with hypertrophic cardiomyopathy

Abstract

Background: The proportion of cats with hypertrophic cardiomyopathy (HCM) that lose systolic anterior motion of the mitral valve (SAM) in the long term is unknown. Hypothesis/Objectives: Cats with HCM will lose SAM in the long term. Loss of SAM will be associated with greater age, longer scan-interval, and altered left ventricular (LV) dimensions. Animals: Sixty unsedated cats with HCM, not receiving beta blockers or pimobendan. Methods: A retrospective cohort study from 2 referral centers. Cats were eligible if they had been diagnosed with HCM and had a repeat echocardiogram ≥1 year later. Clinical and echocardiographic data of the left heart variables were collected. Results: Thirty-eight cats had SAM at the initial scan. After a median follow-up time of 2.1 years (range: 1.0-5.9), 7 cats had lost SAM (18%) and 5 cats (23%) gained SAM. On follow-up, cats with SAM at the initial scan had a larger left atrium (P =.037), lower left atrial fractional shortening (P =.014), greater LV internal diameter in end-systole (P =.002), and lower LV fractional shortening (P