Risk factors for sudden death and heart failure in cats with HCM

Abstract

OBJECTIVES: To evaluate risk factors associated with different types of cardiac death in cats with hypertrophic cardiomyopathy (HCM). ANIMALS: Two hundred fifty-five cats with HCM referred to a veterinary teaching hospital. METHODS: This is a retrospective study. Cats with HCM were identified that had either died within 2 years of diagnosis or were known to be alive 2 years after initial examination. Signalment, physical exam, electrocardiographic and echocardiographic data were analyzed separately for association with death due to congestive heart failure (CHF) vs. aortic thromboembolism (ATE) vs. sudden death. RESULTS: Within 2 years of follow-up, 23/255 (9.0%) cats had died with ATE, 44/255 (17.3%) cats had died with CHF and 12/255 (4.7%) cats had experienced a sudden death, with 141/255 (55.3%) cats still alive at the end of 2 years. Presence of CHF at presentation and reduced left ventricular fractional shortening (FS%) were independently associated with a CHF death within 2 years of diagnosis. Presence of ATE and reduced left atrial fractional shortening (LA-FS%) were independently associated with dying with ATE within 2 years. No multivariable models were generated for risks of dying a sudden death owing to the low event rate, but syncope at presentation and arrhythmias on auscultation were associated with sudden death on univariable analysis. CONCLUSIONS: Asymptomatic cats have a reduced risk of all three types of death. Reduced FS% and a history of CHF independently predict CHF death, and reduced LA-FS% and history of ATE independently predict ATE death. Sudden death is less commonly reported but is associated with syncope.