Prognostic Indicators in Cats with Hypertrophic Cardiomyopathy

Abstract

Background: Left atrial (LA) enlargement, congestive heart failure (CHF), and aortic thromboembolism (ATE) are associated with decreased survival in cats with hypertrophic cardiomyopathy (HCM), but the prognostic value of echocardiographic variables has not been well characterized.Hypothesis/Objectives: We hypothesized that LA echocardiographic variables and assessment of left ventricular (LV) diastolic and systolic function would have prognostic value in cats with HCM.Animals: Two hundred eighty-two cats diagnosed with HCM.Methods: Clinical and echocardiographic records of affected cats seen at the Royal Veterinary College from 2004 to 2009 were retrospectively analyzed. Only cats with echocardiographic confirmation of LV diastolic wall thickness ≥6 mm were included. Outcomes were obtained from clinical records or referring veterinarians and owners.Results: Deaths occurred in 164 cats, of which 107 were believed to have been cardiac deaths. Univariable predictors of an increased risk of cardiac death included older age, absence of a murmur, presence of a gallop sound or arrhythmia, presentation with either CHF or ATE, extreme LV hypertrophy (≥9.0 mm), LV fractional shortening (FS%) ≤30%, regional wall hypokinesis, increased left atrial size, decreased left atrial function, spontaneous echo-contrast/thrombus or both, absence of left ventricular outflow tract obstruction, and a restrictive diastolic filling pattern. Cox's proportional hazard analysis identified LA dysfunction, low LV systolic function, and extreme LV hypertrophy as independent predictors of decreased cardiac survival time.Conclusions and Clinical Importance: Echocardiographic measurement of LA function, extreme LV hypertrophy, and LV systolic function provides important prognostic information in cats with HCM.

Echocardiographic Assessment of Right Ventricular Size and Function in Cats With Hypertrophic Cardiomyopathy

“…The clinical and prognostic value of LA size (determined echocardiographically) in cats with HCM has been repeatedly demonstrated, and thus is often used as a clinical surrogate of clinical severity and hemodynamic burden 5, 19, 31, 32, 33, 34. In our study, LV free wall thickness, RV chamber size, and RV function (as assessed by 2D TAPSE) were independently correlated with LA size.…”

Association between Survival Time and Changes in NT‐proBNP in Cats Treated for Congestive Heart Failure

“…Previously reported variables that have been shown to have an association with survival time in cats with CHF or HCM include body weight, age, body temperature at the time of hospital admission, left atrial size and function, extreme left ventricular hypertrophy, left ventricular systolic function, presence of systolic anterior motion, and cardiac troponin I 35, 36, 37, 44, 45, 46. Although troponin I was not measured, none of the other variables were found to be associated with survival time in the current study, which may be due to the small sample size or to a true lack of association in this population of cats.…”

Management of incidentally detected heart murmurs in dogs and cats

“…Auscultation of other cardiac abnormalities such as a gallop sound or arrhythmia might be even more valuable than the detection of a murmur for identifying cats at increased risk for CHF or arterial thromboembolism. 31 Clients might not recognize clinical signs initially, but a veterinarian can detect extracardiac physical findings that suggest a systemic disorder, and a client could then realize retrospectively that clinical signs were present after they have resolved with treatment. This scenario is particularly relevant for geriatric cats, in which hyperthyroidism, other disorders causing systemic hypertension, and anemia are more prevalent than in younger cats and can cause a nonpathological murmur that resolves with identification and treatment of the underlying disorder (Figure 6).…”